[
  {
    "question": "Compounds that are capable of accepting electrons, such as o 2 or f2, are called what?",
    "distractor3": "residues",
    "distractor1": "antioxidants",
    "distractor2": "Oxygen",
    "correct_answer": "oxidants",
    "support": "Oxidants and Reductants Compounds that are capable of accepting electrons, such as O 2 or F2, are calledoxidants (or oxidizing agents) because they can oxidize other compounds. In the process of accepting electrons, an oxidant is reduced. Compounds that are capable of donating electrons, such as sodium metal or cyclohexane (C6H12), are calledreductants (or reducing agents) because they can cause the reduction of another compound. In the process of donating electrons, a reductant is oxidized. These relationships are summarized in Equation 3.30: Equation 3.30 Saylor URL: http://www. saylor. org/books."
  },
  {
    "question": "What kind of viscosity is found in long-chain hydrocarbons?",
    "distractor3": "intense viscosity",
    "distractor1": "increased viscosity",
    "distractor2": "low viscosity",
    "correct_answer": "highly viscous",
    "support": "There is also a correlation between viscosity and molecular shape. Liquids consisting of long, flexible molecules tend to have higher viscosities than those composed of more spherical or shorter-chain molecules. The longer the molecules, the easier it is for them to become “tangled” with one another, making it more difficult for them to move past one another. London dispersion forces also increase with chain length. Due to a combination of these two effects, long-chain hydrocarbons (such as motor oils) are highly viscous."
  },
  {
    "question": "How does a neon light produce visible light?",
    "distractor3": "mitosis",
    "distractor1": "luminescence",
    "distractor2": "radiation",
    "correct_answer": "electroluminescence",
    "support": "A neon light produces visible light by electroluminescence. The bulb is a glass tube that contains the noble gas neon. When electricity passes through the gas, it excites electrons of neon atoms, causing them to give off visible light. Neon produces red light. Other noble gases are also used in lights, and they produce light of different colors. For example, krypton produces violet light, and argon produces blue light."
  },
  {
    "question": "What are the two most common silicates?",
    "distractor3": "Micas\t and quartz",
    "distractor1": "Olivine and quartz",
    "distractor2": "Micas\t and feldspar",
    "correct_answer": "feldspar and quartz",
    "support": "Feldspar and quartz are the two most common silicates. In beryl, the silicate pyramids join together as rings. Biotite is mica. It can be broken apart into thin, flexible sheets. Compare the beryl and the biotite shown in Figure below ."
  },
  {
    "question": "Ionic compounds have strong electrostatic attractions between oppositely charged ions in this?",
    "distractor3": "occasional array",
    "distractor1": "incorrect array",
    "distractor2": "normal array",
    "correct_answer": "regular array",
    "support": "Ionic compounds have strong electrostatic attractions between oppositely charged ions in a regular array. The lattice energy (U) of an ionic substance is defined as the energy required to dissociate the solid into gaseous ions; U can be calculated from the charges on the ions, the arrangement of the ions in the solid, and the internuclear distance. Because U depends on the product of the ionic charges, substances with dior tripositive cations and/or di- or trinegative anions tend to have higher lattice energies than their singly charged counterparts. Higher lattice energies typically result in higher melting points and increased hardnessbecause more thermal energy is needed to overcome the forces that hold the ions together. Lattice energies cannot be measured directly but are obtained from a thermochemical cycle called the Born–Haber cycle, in which Hess’s law is used to calculate the lattice energy from the measured enthalpy of formation of the ionic compound, along with other thermochemical data. The Born–Haber cycle can be used to predict which ionic compounds are likely to form. Sublimation, the conversion of a solid directly to a gas, has an accompanying enthalpy change called the enthalpy of sublimation."
  },
  {
    "question": "Paracrine signals move by what method through the extracellular matrix?",
    "distractor3": "transfusion",
    "distractor1": "osmosis",
    "distractor2": "deposition",
    "correct_answer": "diffusion",
    "support": "Paracrine Signaling Signals that act locally between cells that are close together are called paracrine signals. Paracrine signals move by diffusion through the extracellular matrix. These types of signals usually elicit quick responses that last only a short amount of time. In order to keep the response localized, paracrine ligand molecules are normally quickly degraded by enzymes or removed by neighboring cells. Removing the signals will reestablish the concentration gradient for the signal, allowing them to quickly diffuse through the intracellular space if released again. One example of paracrine signaling is the transfer of signals across synapses between nerve cells. A nerve cell consists of a cell body, several short, branched extensions called dendrites that receive stimuli, and a long extension called an axon, which transmits signals to other nerve cells or muscle cells. The junction between nerve cells where signal transmission occurs is called a synapse. A synaptic signal is a chemical signal that travels between nerve cells. Signals within the nerve cells are propagated by fast-moving electrical impulses. When these impulses reach the end of the axon, the signal continues on to a dendrite of the next cell by the release of chemical ligands called neurotransmitters by the presynaptic cell (the cell emitting the signal). The neurotransmitters are transported across the very small distances between nerve cells, which are called chemical synapses (Figure 9.3). The small distance between nerve cells allows the signal to travel quickly; this enables an immediate response, such as, Take your hand off the stove! When the neurotransmitter binds the receptor on the surface of the postsynaptic cell, the electrochemical potential of the target cell changes, and the next electrical impulse is launched. The neurotransmitters that are released into the chemical synapse are degraded quickly or get reabsorbed by the presynaptic cell so that the recipient nerve cell can recover quickly and be prepared to respond rapidly to the next synaptic signal."
  },
  {
    "question": "Where is energy stored in a chemical substance?",
    "distractor3": "inside atoms",
    "distractor1": "on the surface",
    "distractor2": "in molecules",
    "correct_answer": "between atoms",
    "support": "energy that is stored in the connections between atoms in a chemical substance."
  },
  {
    "question": "What is the most abundant metal of the earth's crust?",
    "distractor3": "magnetite",
    "distractor1": "calcium",
    "distractor2": "copper",
    "correct_answer": "aluminum",
    "support": "Metals represent approximately 25% of the elemental makeup of the Earth's crust. The bulk of these metals, primarily aluminum, iron, calcium, sodium, potassium, and magnesium, are typically found in combined form. The most abundant metal is aluminum, which occurs almost exclusively as the ionic mineral bauxite. The other most common metals, including iron, sodium, potassium, magnesium, and calcium, are also found primarily as the cationic portion of an ionic compound. Very few metals actually occur naturally as pure substances. The ones that do are often referred to as precious or semi-precious metals."
  },
  {
    "question": "The strength of a base depends on the concentration of _______ it produces when dissolved in water?",
    "distractor3": "monoxide ions",
    "distractor1": "combustion ions",
    "distractor2": "calcium ions",
    "correct_answer": "hydroxide ions",
    "support": "The strength of a base depends on the concentration of hydroxide ions it produces when dissolved in water. For example, sodium hydroxide completely breaks down into ions in water, so it is a strong base. However, only a fraction of ammonia breaks down into ions, so it is a weak base."
  },
  {
    "question": "Pairs of nitrogenous bases are attached to each other by?",
    "distractor3": "magnetism",
    "distractor1": "potassium bonds",
    "distractor2": "ionic bonds",
    "correct_answer": "hydrogen bonds",
    "support": ""
  },
  {
    "question": "The overall voltage of the battery is therefore the sum of ________ of the individual cells.",
    "distractor3": "weights",
    "distractor1": "currents",
    "distractor2": "resistances",
    "correct_answer": "voltages",
    "support": "Batteries There are two basic kinds of batteries: disposable, or primary, batteries, in which the electrode reactions are effectively irreversible and which cannot be recharged; andrechargeable, or secondary, batteries, which form an insoluble product that adheres to the electrodes. These batteries can be recharged by applying an electrical potential in the reverse direction. The recharging process temporarily converts a rechargeable battery from a galvanic cell to an electrolytic cell. Batteries are cleverly engineered devices that are based on the same fundamental laws as galvanic cells. The major difference between batteries and the galvanic cells we have previously described is that commercial batteries use solids or pastes rather than solutions as reactants to maximize the electrical output per unit mass. The use of highly concentrated or solid reactants has another beneficial effect: the concentrations of the reactants and the products do not change greatly as the battery is discharged; consequently, the output voltage remains remarkably constant during the discharge process. This behavior is in contrast to that of the Zn/Cu cell, whose output decreases logarithmically as the reaction proceeds (Figure 19.11 \"The Variation of \"). When a battery consists of more than one galvanic cell, the cells are usually connected in series—that is, with the positive (+) terminal of one cell connected to the negative (−) terminal of the next, and so forth. The overall voltage of the battery is therefore the sum of the voltages of the individual cells."
  },
  {
    "question": "What instrument is used to make very sensitive mass measurements in a laboratory, usually in grams?",
    "distractor3": "scale",
    "distractor1": "speedometer",
    "distractor2": "thermometer",
    "correct_answer": "analytical balance",
    "support": "An analytical balance makes very sensitive mass measurements in a laboratory, usually in grams."
  },
  {
    "question": "The temperature at which a substance melts is called its what point?",
    "distractor3": "freezing",
    "distractor1": "boiling",
    "distractor2": "change",
    "correct_answer": "melting",
    "support": "The temperature at which a substance melts is called its melting point. Melting point is a physical property of matter. The gold pictured in the Figure above , for example, has a melting point of 1064°C. This is a high melting point, and most other metals also have high melting points. The melting point of ice, in comparison, is much lower at 0°C. Many substances have even lower melting points. For example, the melting point of oxygen is -222°C."
  },
  {
    "question": "What type of bonds are formed by the side-to-side overlap of p orbitals?",
    "distractor3": "theta bonds",
    "distractor1": "sigma bonds",
    "distractor2": "omega bonds",
    "correct_answer": "pi bonds",
    "support": "Sigma bonds are formed by the end-to-end overlap of bonding orbitals. Pi bonds are formed by the side-to-side overlap of p orbitals. Single bonds are normally sigma bonds. A double or triple bond consists of one sigma bond and either one or two pi bonds."
  },
  {
    "question": "The electrode at which oxidation occurs is called?",
    "distractor3": "calomel",
    "distractor1": "diode",
    "distractor2": "cathode",
    "correct_answer": "the anode",
    "support": "The electrode at which oxidation occurs is called the anode . The zinc anode gradually diminishes as the cell operates due to the loss of zinc metal. The zinc ion concentration in the half-cell increases. Because of the production of electrons at the anode, it is labeled as the negative electrode."
  },
  {
    "question": "What is required to move or change matter from one state to another?",
    "distractor3": "evolution",
    "distractor1": "food",
    "distractor2": "gravity",
    "correct_answer": "energy",
    "support": "Energy provides the ability to move or change matter from one state to another (for example, from solid to liquid). Every living thing needs energy to live and grow. Your body gets its energy from food, but that is only a small part of the energy you use every day. Cooking your food takes energy, and so does keeping it cold in the refrigerator or the freezer. The same is true for heating or cooling your home. Whether you are turning on a light in the kitchen or riding in a car to school, you are using energy. Billions of people all around the world use energy, so there is a huge demand for resources to provide all of this energy. Why do we need so much energy? The main reason is that almost everything that happens on Earth involves energy."
  },
  {
    "question": "Natural gas is the predominately made up of?",
    "distractor3": "sulfur",
    "distractor1": "hydrogen",
    "distractor2": "carbon",
    "correct_answer": "methane",
    "support": "Natural gas is mostly methane. Natural gas is usually found with petroleum. People prefer to burn natural gas when possible because it is relatively clean."
  },
  {
    "question": "What contains positive protons and neutral neutrons?",
    "distractor3": "epidermis",
    "distractor1": "electrons",
    "distractor2": "ions",
    "correct_answer": "nucleus",
    "support": "The nucleus is at the center of the atom. It contains positive protons and neutral neutrons. Negative electrons constantly move about the nucleus."
  },
  {
    "question": "What is the diffusion of water through a semipermeable membrane down its concentration gradient",
    "distractor3": "Permable",
    "distractor1": "nutrients",
    "distractor2": "mirrors",
    "correct_answer": "osmosis",
    "support": "Figure 3.7 Osmosis Osmosis is the diffusion of water through a semipermeable membrane down its concentration gradient. If a membrane is permeable to water, though not to a solute, water will equalize its own concentration by diffusing to the side of lower water concentration (and thus the side of higher solute concentration). In the beaker on the left, the solution on the right side of the membrane is hypertonic."
  },
  {
    "question": "Water can be broken down into hydrogen and oxygen gases by the addition of what?",
    "distractor3": "demand",
    "distractor1": "motion",
    "distractor2": "mineral",
    "correct_answer": "energy",
    "support": "Chemistry in Everyday Life Decomposition of Water / Production of Hydrogen Water consists of the elements hydrogen and oxygen combined in a 2 to 1 ratio. Water can be broken down into hydrogen and oxygen gases by the addition of energy. One way to do this is with a battery or power supply, as shown in (Figure 1.15)."
  },
  {
    "question": "When exposed to ultraviolet, some substances, such as minerals, glow in characteristic visible wavelengths, a process called this?",
    "distractor3": "pigment",
    "distractor1": "plasma",
    "distractor2": "chemical reaction",
    "correct_answer": "fluorescence",
    "support": "When exposed to ultraviolet, some substances, such as minerals, glow in characteristic visible wavelengths, a process called fluorescence. So-called black lights emit ultraviolet to cause posters and clothing to fluoresce in the visible. Ultraviolet is also used in special microscopes to detect details smaller than those observable with longer-wavelength visible-light microscopes. Things Great and Small: A Submicroscopic View of X-Ray Production X-rays can be created in a high-voltage discharge. They are emitted in the material struck by electrons in the discharge current. There are two mechanisms by which the electrons create X-rays. The first method is illustrated in Figure 24.18. An electron is accelerated in an evacuated tube by a high positive voltage. The electron strikes a metal plate (e. , copper) and produces X-rays. Since this is a high-voltage discharge, the electron gains sufficient energy to ionize the atom."
  },
  {
    "question": "What is a fiber that is found only in mammals?",
    "distractor3": "feathers",
    "distractor1": "muscle",
    "distractor2": "muscle",
    "correct_answer": "hair",
    "support": "Hair is a fiber that is found only in mammals. Its main component is keratin. A hair shaft consists of dead, keratin-filled cells that overlap each other like the shingles on a roof (see Figure below ). Like roof shingles, the overlapping cells help shed water from the hair."
  },
  {
    "question": "What forms when secondary alcohols oxidize?",
    "distractor3": "electrons",
    "distractor1": "chromosomes",
    "distractor2": "ions",
    "correct_answer": "ketones",
    "support": "Secondary alcohols are oxidized to form ketones."
  },
  {
    "question": "What forms when nitrogen and sulfur oxides in air dissolve in rain?",
    "distractor3": "acid snow",
    "distractor1": "carbon rain",
    "distractor2": "dioxide rain",
    "correct_answer": "acid rain",
    "support": "Acid rain forms when nitrogen and sulfur oxides in air dissolve in rain ( Figure below ). This forms nitric and sulfuric acids. Both are strong acids. Acid rain with a pH as low as 4.0 is now common in many areas. Acid fog may be even more acidic than acid rain. Fog with a pH as low as 1.7 has been recorded. That’s the same pH as toilet bowl cleaner!."
  },
  {
    "question": "Which property of diamond makes it so hard?",
    "distractor3": "carbon bonds",
    "distractor1": "non-covalent bonds",
    "distractor2": "metal-metal bonds",
    "correct_answer": "chemical bonds",
    "support": "Diamond is the hardest natural material known on Earth. Yet diamond is just pure carbon. What is special about this element that makes diamond so hard? Bonds. Chemical bonds. In a perfect diamond crystal, each C atom makes four connections—bonds—to four other C atoms in a three-dimensional matrix. Four is the greatest number of bonds that is commonly made by atoms, so C atoms maximize their interactions with other atoms. This threedimensional array of connections extends throughout the diamond crystal, making it essentially one large molecule. Breaking a diamond means breaking every bond at once. Also, the bonds are moderately strong. There are stronger interactions known, but the carboncarbon connection is fairly strong itself. Not only does a person have to break many connections at once, but also the bonds are strong connections from the start. There are other substances that have similar bonding arrangements as diamond does. Silicon dioxide and boron nitride have some similarities, but neither of them comes close to the ultimate hardness of diamond. How do atoms make compounds? Typically they join together in such a way that they lose their identities as elements and adopt a new identity as a compound. These joins are called chemical bonds. But how do atoms join together? Ultimately, it all comes down to electrons. Before we discuss how electrons interact, we need to introduce a tool to simply illustrate electrons in an atom."
  },
  {
    "question": "What forms when nitrogen and oxygen combine at high temperatures?",
    "distractor3": "calcium oxides",
    "distractor1": "hydrocarbons",
    "distractor2": "nitric acid",
    "correct_answer": "nitrogen oxides",
    "support": "Nitrogen oxides include nitric oxide (NO) and nitrogen dioxide (NO 2 ). Nitrogen oxides form when nitrogen and oxygen combine at high temperatures. This occurs in hot exhausts from vehicles, factories, and power plants."
  },
  {
    "question": "What holds together adenine and thymine?",
    "distractor3": "helium bonds",
    "distractor1": "covalent bonds",
    "distractor2": "potassium bonds",
    "correct_answer": "hydrogen bonds",
    "support": "The base-pairing nature of DNA. Adenine always pairs with thymine, and they are held together with two hydrogen bonds. The guanine-cytosine base pair is held together with three hydrogen bonds. Note that one sugar-phosphate backbone is in the 5’ → 3’ direction, with the other strand in the opposite 3’ → 5’ orientation. Notice that the 5'-end begins with a free (not attached to the sugar of another nucleotide) phosphate group, while the 3'-end has a free (not attached to the phosphate group of another nucleotide) deoxyribose sugar."
  },
  {
    "question": "Compound forms when atoms of nonmetals form molecules that are held together by what?",
    "distractor3": "dissonance bonds",
    "distractor1": "phenotype bonds",
    "distractor2": "magnetic bonds",
    "correct_answer": "covalent bonds",
    "support": "Compound forms when atoms of nonmetals form molecules that are held together by covalent bonds."
  },
  {
    "question": "The cell walls of what organisms are strengthened by chitin, unlike plant cell walls, which contain cellulose?",
    "distractor3": "yeast",
    "distractor1": "virus",
    "distractor2": "bacterium",
    "correct_answer": "fungi",
    "support": ""
  },
  {
    "question": "Humans cannot digest what primary structural material of plants, which is one of the most abundant organic substances on earth?",
    "distractor3": "zinc",
    "distractor1": "sulfur",
    "distractor2": "carbonate",
    "correct_answer": "cellulose",
    "support": "Starches (a) and cellulose (b) differ in the connection between glucose units and the amount of branching in the molecule. Starches can be coiled or branched, whereas cellulose, the primary structural material of plants, has long, unbranched chains held together by hydrogen bonds. Cellulose is the primary structural material of plants and one of the most abundant organic substances on Earth. Because our enzymes are not able to hydrolyze the bonds between the glucose units in cellulose, we are unable to digest it. A recently marketed product containing a high percentage of cellulose was sold as a dietetic substance for rapid weight loss, but those who consumed it experienced severe intestinal discomfort because the cellulose could not be digested. The product was quickly removed from the market."
  },
  {
    "question": "The glass hydrometer is filled with air and weighted with lead at the bottom. it floats highest in the densest fluids and has been calibrated and labeled so that you can read this from it?",
    "distractor3": "density",
    "distractor1": "volume",
    "distractor2": "mass",
    "correct_answer": "specific gravity",
    "support": "CHAPTER SUMMARY 12.1 Mendel’s Experiments and the Laws of Probability Working with garden pea plants, Mendel found that crosses between parents that differed by one trait produced F1 offspring that all expressed the traits of one parent. Observable traits are referred to as dominant, and non-expressed traits are described as recessive. When the offspring in Mendel’s experiment were self-crossed, the F2 offspring exhibited the dominant trait or the recessive trait in a 3:1 ratio, confirming that the recessive trait had been transmitted faithfully from the original P0 parent. Reciprocal crosses generated identical F1 and F2 offspring ratios. By examining sample sizes, Mendel showed that his crosses behaved reproducibly according to the laws of probability, and that the traits were inherited as independent events. Two rules in probability can be used to find the expected proportions of offspring of different traits from different crosses. To find the probability of two or more independent events occurring together, apply the product rule and multiply the probabilities of the individual events. The use of the word “and” suggests the appropriate application of the product rule. To find the probability of two or more events occurring in combination, apply the sum rule and add their individual probabilities together. The use of the word “or” suggests the appropriate application of the sum rule."
  },
  {
    "question": "The ionic end of a detergent can either be a sulfate or what?",
    "distractor3": "phosphate",
    "distractor1": "molecule",
    "distractor2": "calcite",
    "correct_answer": "sulfonate",
    "support": "Figure 11.33 Detergents contain a nonpolar hydrocarbon end (blue) and an ionic end (red). The ionic end can be either a sulfate or a sulfonate. The length of the hydrocarbon end can vary from detergent to detergent."
  },
  {
    "question": "What type of change is undergone when the physical properties of a substance are changed?",
    "distractor3": "atmospheric",
    "distractor1": "thermal",
    "distractor2": "genetic",
    "correct_answer": "physical",
    "support": "Any time the physical properties of a substance are changed, we can say the substance has undergone a physical change . All substances undergo physical changes where there is a change in the form of the substance but not in its chemical composition. For instance, the grinding of granular sugar into powdered sugar is a physical change. Similarly, dissolving sugar in water is a physical change. We can also use physical changes to separate mixtures into their components. There are a variety of methods used, and the best procedure depends largely on the nature of the mixture. Depending on the states of matter involved, the relative sizes of the mixtures components, and whether the mixture is homogeneous or heterogeneous will determine the necessary separation technique."
  },
  {
    "question": "Layers of what create a volcano?",
    "distractor3": "crust",
    "distractor1": "rock",
    "distractor2": "limestone",
    "correct_answer": "lava",
    "support": "Magma beneath a volcano erupts onto the volcano’s surface. Layer upon layer of lava creates a volcano."
  },
  {
    "question": "Connecting a magnesium rod to an underground steel pipeline protects the pipeline from corrosion. because magnesium (e° = −2.37 v) is much more easily oxidized than iron (e° = −0.45 v), the mg rod acts as the anode in a what?",
    "distractor3": "voltaic cell",
    "distractor1": "anode cell",
    "distractor2": "stimulation cell",
    "correct_answer": "galvanic cell",
    "support": "Connecting a magnesium rod to an underground steel pipeline protects the pipeline from corrosion. Because magnesium (E° = −2.37 V) is much more easily oxidized than iron (E° = −0.45 V), the Mg rod acts as the anode in a galvanic cell. The pipeline is therefore forced to act as the cathode at which oxygen is reduced. The soil between the anode and the cathode acts as a salt bridge that completes the electrical circuit and maintains electrical neutrality. As Mg(s) is oxidized to Mg2+ at the anode, anions in the soil, such as nitrate, diffuse toward the anode to neutralize the positive charge. Simultaneously, cations in the soil, such as H+ or NH4+, diffuse toward the cathode, where they replenish the protons that are consumed as oxygen is reduced. A similar strategy uses many miles of somewhat less reactive zinc wire to protect the Alaska oil pipeline."
  },
  {
    "question": "Pure carbon can exist in different forms, depending on how its atoms are arranged. the forms include diamond, graphite, and what else?",
    "distractor3": "ligands",
    "distractor1": "calcites",
    "distractor2": "lead",
    "correct_answer": "fullerenes",
    "support": "Pure carbon can exist in different forms, depending on how its atoms are arranged. The forms include diamond, graphite, and fullerenes. All three forms exist as crystals, but they have different structures. Their different structures, in turn, give them different properties. You can learn more about them in Table below ."
  },
  {
    "question": "Chitin, also found in the exoskeleton of insects, gives structural strength to the cell walls of fungi. the cell wall protects the cell from what?",
    "distractor3": "starvation and predators",
    "distractor1": "fermentation and predators",
    "distractor2": "entrainment and predators",
    "correct_answer": "desiccation and predators",
    "support": "Like plant cells, fungal cells are surrounded by a thick cell wall; however, the rigid layers contain the complex polysaccharides chitin and glucan and not cellulose that is used by plants. Chitin, also found in the exoskeleton of insects, gives structural strength to the cell walls of fungi. The cell wall protects the cell from desiccation and predators. Fungi have plasma membranes similar to other eukaryotes, except that the structure is stabilized by ergosterol, a steroid molecule that functions like the cholesterol found in animal cell membranes. Most members of the kingdom Fungi are nonmotile. Flagella are produced only by the gametes in the primitive division Chytridiomycota. Growth and Reproduction The vegetative body of a fungus is called a thallus and can be unicellular or multicellular. Some fungi are dimorphic because they can go from being unicellular to multicellular depending on environmental conditions. Unicellular fungi are generally referred to as yeasts. Saccharomyces cerevisiae (baker’s yeast) and Candida species (the agents of thrush, a common fungal infection) are examples of unicellular fungi. Most fungi are multicellular organisms. They display two distinct morphological stages: vegetative and reproductive. The vegetative stage is characterized by a tangle of slender thread-like structures called hyphae (singular, hypha), whereas the reproductive stage can be more conspicuous. A mass of hyphae is called a mycelium (Figure 13.22). It can grow on a surface, in soil or decaying material, in a liquid, or even in or on living tissue. Although individual hypha must be observed under a microscope, the mycelium of a fungus can be very large with some species truly being “the fungus humongous. ” The giant Armillaria ostoyae (honey mushroom) is considered the largest organism on Earth, spreading across over 2,000 acres of underground soil in eastern Oregon; it is estimated to be at least 2,400 years old."
  },
  {
    "question": "The lattice energy is usually the most important energy factor in determining the stability of what?",
    "distractor3": "saline compound",
    "distractor1": "harmonic compound",
    "distractor2": "magnetic compound",
    "correct_answer": "ionic compound",
    "support": "The lattice energy is usually the most important energy factor in determining the stability of an ionic compound."
  },
  {
    "question": "Exothermic reactions, like all chemical reactions, require what to get started?",
    "distractor3": "specific energy",
    "distractor1": "surface energy",
    "distractor2": "membrane energy",
    "correct_answer": "activation energy",
    "support": "All chemical reactions, including exothermic reactions, need activation energy to get started."
  },
  {
    "question": "A solenoid wrapped around a bar of iron or other ferromagnetic material forms what?",
    "distractor3": "compress",
    "distractor1": "impoundment",
    "distractor2": "compass",
    "correct_answer": "electromagnet",
    "support": "Solenoids are the basis of electromagnets. An electromagnet is a solenoid wrapped around a bar of iron or other ferromagnetic material (see Figure below ). The electromagnetic field of the solenoid magnetizes the iron bar by aligning its magnetic domains. The combined magnetic force of the magnetized iron bar and the wire coil makes an electromagnet very strong. In fact, electromagnets are the strongest magnets made. Some of them are strong enough to lift a train. The maglev train described earlier, in the lesson \"Electricity and Magnetism,\" contains permanent magnets. Strong electromagnets in the track repel the train magnets, causing the train to levitate above the track."
  },
  {
    "question": "The force of attraction between a positively charged metal ion and the valence electrons it shares with other ions of the metal is called?",
    "distractor3": "temporal bond",
    "distractor1": "ionic bond",
    "distractor2": "metallic yield",
    "correct_answer": "metallic bond",
    "support": "A metallic bond is the force of attraction between a positively charged metal ion and the valence electrons it shares with other ions of the metal. The electrons move freely around the positive ions, which form a lattice-like structure."
  },
  {
    "question": "What are the majority of solution properties dependent upon?",
    "distractor3": "acid state of solute",
    "distractor1": "similar state of solute",
    "distractor2": "gas state of solute",
    "correct_answer": "chemical state of solute",
    "support": "The properties of a solution are different from those of either the pure solute(s) or solvent. Many solution properties are dependent upon the chemical identity of the solute. Compared to pure water, a solution of hydrogen chloride is more acidic, a solution of ammonia is more basic, a solution of sodium chloride is more dense, and a solution of sucrose is more viscous. There are a few solution properties, however, that depend only upon the total concentration of solute species, regardless of their identities. These colligative properties include vapor pressure lowering, boiling point elevation, freezing point depression, and osmotic pressure. This small set of properties is of central importance to many natural phenomena and technological applications, as will be described in this module."
  },
  {
    "question": "What makes up the dense outer layer of bones?",
    "distractor3": "plasma",
    "distractor1": "adipose tissue",
    "distractor2": "ligaments",
    "correct_answer": "compact bone",
    "support": "Compact bone makes up the dense outer layer of bone. It is very hard and strong."
  },
  {
    "question": "What forms when one substances dissolves in another?",
    "distractor3": "complex",
    "distractor1": "a transition",
    "distractor2": "concentrate",
    "correct_answer": "a solution",
    "support": "A solution forms when one substance dissolves in another. The substance that dissolves is called the solute. The substance that dissolves it is called the solvent."
  },
  {
    "question": "How many atoms does water contain?",
    "distractor3": "9",
    "distractor1": "4",
    "distractor2": "6",
    "correct_answer": "3",
    "support": "Water, like carbon, has a special role in living things. It is needed by all known forms of life. Water is a simple molecule, containing just three atoms. Nonetheless, water’s structure gives it unique properties that help explain why it is vital to all living organisms."
  },
  {
    "question": "What must be combined with a halogen to give it a positive oxidation number?",
    "distractor3": "carbon",
    "distractor1": "nitrogen",
    "distractor2": "calcium",
    "correct_answer": "oxygen",
    "support": "Halogens (Cl, Br, I) have negative oxidation numbers when they form halide compounds. When combined with oxygen, they have positive numbers. In the chlorate ion (ClO 3 - ), the oxidation number of Cl +5, and the oxidation number of O is -2."
  },
  {
    "question": "What is the term for the force that a magnet exerts on certain materials?",
    "distractor3": "potential force",
    "distractor1": "positive force",
    "distractor2": "gravitational force",
    "correct_answer": "magnetic force",
    "support": "The force that a magnet exerts on certain materials is called magnetic force . Like electric force, magnetic force is exerted over a distance and includes forces of attraction and repulsion. North and south poles of two magnets attract each other, while two north poles or two south poles repel each other."
  },
  {
    "question": "What is a mixture of a solute in a solvent called?",
    "distractor3": "transition",
    "distractor1": "link",
    "distractor2": "structure",
    "correct_answer": "solution",
    "support": "Imagine you have a cup that has 100ml water, and you add 15g of table sugar to the water. The sugar dissolves and the mixture that is now in the cup is made up of a solute (the sugar) that is dissolved in the solvent (the water). The mixture of a solute in a solvent is called a solution ."
  },
  {
    "question": "Proteins are polymers of what kind of acids?",
    "distractor3": "acetic",
    "distractor1": "lipids",
    "distractor2": "lactic",
    "correct_answer": "amino",
    "support": "Proteins are polymers of amino acids, which act as the monomers."
  },
  {
    "question": "A rock that contains important minerals is called what, a term associated with mining?",
    "distractor3": "gem",
    "distractor1": "jewel",
    "distractor2": "coal",
    "correct_answer": "ore",
    "support": "An ore is a rock that contains important minerals."
  },
  {
    "question": "Silver is an example of a mineral containing only one kind of what?",
    "distractor3": "chemical",
    "distractor1": "matter",
    "distractor2": "mass",
    "correct_answer": "element",
    "support": "All minerals have a definite chemical makeup. A few minerals are made of only one kind of element. Silver is a mineral made only of silver atoms. Diamond and graphite are both made only of the element carbon."
  },
  {
    "question": "Besides the size of their crystals, how are igneous rocks grouped?",
    "distractor3": "by color",
    "distractor1": "by shapes",
    "distractor2": "impurities they contain",
    "correct_answer": "minerals they contain",
    "support": "Igneous rocks are grouped by the size of their crystals and the minerals they contain. The minerals in igneous rocks are grouped into families. Some contain mostly lighter colored minerals, some have a combination of light and dark minerals, and some have mostly darker minerals. The combination of minerals is determined by the composition of the magma. Magmas that produce lighter colored minerals are higher in silica. These create rocks such as granite and rhyolite. Darker colored minerals are found in rocks such as gabbro and basalt."
  },
  {
    "question": "What kind of rock layer makes up the bottom of an aquifer?",
    "distractor3": "crystalline",
    "distractor1": "invisible",
    "distractor2": "porous",
    "correct_answer": "impermeable",
    "support": "A rock layer must be porous and permeable to be a good aquifer. An impermeable layer makes up the bottom of an aquifer."
  },
  {
    "question": "The components of a mixture keep their own identity when they combine, so they retain what type of properties, such as boiling point and ability to dissolve?",
    "distractor3": "thermal",
    "distractor1": "thermal",
    "distractor2": "internal",
    "correct_answer": "physical",
    "support": "The components of a mixture keep their own identity when they combine, so they retain their physical properties. Examples of physical properties include boiling point, ability to dissolve, and particle size. When components of mixtures vary in physical properties such as these, processes such as boiling, dissolving, or filtering can be used to separate them."
  },
  {
    "question": "A thermite reaction is thermodynamically spontaneous, and because it is associated with a significant release of heat, it is regarded as what?",
    "distractor3": "endothermic",
    "distractor1": "biochemical",
    "distractor2": "endotropic",
    "correct_answer": "exothermic",
    "support": "Thermodynamic spontaneity. The highly exothermic and dramatic thermite reaction is thermodynamically spontaneous. Reactants of aluminum and a metal oxide, usually iron, which are stable at room temperature, are ignited either in the presence of heat or by the reaction of potassium permanganate and glycerin. The resulting products are aluminum oxide, free and molten elemental metal, and a great deal of heat, which makes this an excellent method for on-site welding. Because this reaction has its own oxygen supply, it can be used for underwater welding as well."
  },
  {
    "question": "Each bond includes a sharing of electrons between atoms. two electrons are shared in a single bond; four electrons are shared in a double bond; and six electrons are shared in this?",
    "distractor3": "magnetic bond",
    "distractor1": "ionic bond",
    "distractor2": "quadruple bond",
    "correct_answer": "triple bond",
    "support": "Each bond includes a sharing of electrons between atoms. Two electrons are shared in a single bond; four electrons are shared in a double bond; and six electrons are shared in a triple bond."
  },
  {
    "question": "Salicylic acid is used in the synthesis of acetylsalicylic acid, or more commonly called?",
    "distractor3": "Tylenol",
    "distractor1": "smelling salts",
    "distractor2": "antacid",
    "correct_answer": "aspirin",
    "support": "Salicylic acid is used in the synthesis of acetylsalicylic acid, or aspirin. One gram dissolves in 460 mL of water to create a saturated solution with a pH of 2.40."
  },
  {
    "question": "How many types of molecular orbitals can form from the overlap of two atomic s orbitals on adjacent atoms?",
    "distractor3": "ten",
    "distractor1": "three",
    "distractor2": "six",
    "correct_answer": "two",
    "support": "There are two types of molecular orbitals that can form from the overlap of two atomic s orbitals on adjacent atoms. The two types are illustrated in Figure 8.29. The in-phase combination produces a lower energy σs molecular orbital (read as \"sigma-s\") in which most of the electron density is directly between the nuclei. The out-of-phase addition (which can also be thought of as subtracting the wave functions) produces a higher energy molecular orbital (read as \"sigma-s-star\") molecular orbital in which there is a node between the nuclei. The asterisk signifies that the orbital is an antibonding orbital. Electrons in a σs orbital are attracted by both nuclei at the same time and are more stable (of lower energy) than they would be in the isolated atoms. Adding electrons to these orbitals creates a force that holds the two nuclei together, so we call these orbitals bonding orbitals. Electrons in the σ*s orbitals are located well away from the region between the two nuclei. The attractive force between the nuclei and these electrons pulls the two nuclei apart. Hence, these orbitals are called antibonding orbitals. Electrons fill the lower-energy bonding orbital before the higher-energy antibonding orbital, just as they fill lower-energy atomic orbitals before they fill higher-energy atomic orbitals."
  },
  {
    "question": "Atoms of different elements have different numbers of what?",
    "distractor3": "nucleus",
    "distractor1": "electrons",
    "distractor2": "neutrons",
    "correct_answer": "protons",
    "support": "All protons are identical. For example, hydrogen protons are exactly the same as protons of helium and all other elements, or pure substances. However, atoms of different elements have different numbers of protons. In fact, atoms of any given element have a unique number of protons that is different from the numbers of protons of all other elements. For example, a hydrogen atom has just one proton, whereas a helium atom has two protons. The number of protons in an atom determines the electrical charge of the nucleus. The nucleus also contains neutrons, but they are neutral in charge. The one proton in a hydrogen nucleus, for example, gives it a charge of +1, and the two protons in a helium nucleus give it a charge of +2. To learn more about the relationship between protons and elements, go to this URL:."
  },
  {
    "question": "What do induction cooktops have under their surface?",
    "distractor3": "screws",
    "distractor1": "Chambers",
    "distractor2": "clumps",
    "correct_answer": "electromagnets",
    "support": "Induction cooktops have electromagnets under their surface. The magnetic field is varied rapidly producing eddy currents in the base of the pot, causing the pot and its contents to increase in temperature. Induction cooktops have high efficiencies and good response times but the base of the pot needs to be ferromagnetic, iron or steel for induction to work."
  },
  {
    "question": "Gabbro is a dark dense rock that can be found in what?",
    "distractor3": "soil",
    "distractor1": "surface crust",
    "distractor2": "mantle",
    "correct_answer": "oceanic crust",
    "support": "Mark A. Wilson (Department of Geology, The College of Wooster). Gabbro is a dark dense rock that can be found in oceanic crust . Public Domain."
  },
  {
    "question": "Two smaller isotopes, more neutrons, and heat energy are the products of what type of reaction?",
    "distractor3": "fusion",
    "distractor1": "Reaction",
    "distractor2": "diffusion",
    "correct_answer": "fission",
    "support": "Nuclear fission reactions involve collision of a slow neuron with an element, usually uranium. The products of a fission reaction are two smaller isotopes, more neutrons, and heat energy."
  },
  {
    "question": "Matter is made up of a mixture of things called what?",
    "distractor3": "structures",
    "distractor1": "segments",
    "distractor2": "compounds",
    "correct_answer": "elements",
    "support": "Matter is made up of a mixture of things called elements. Elements are substances that cannot be broken down into simpler substances. There are more than 100 known elements, and 92 occur naturally around us. The others have been made only in the laboratory."
  },
  {
    "question": "What is the conversion of a solid to a gas called?",
    "distractor3": "education",
    "distractor1": "speciation",
    "distractor2": "amplification",
    "correct_answer": "sublimation",
    "support": "(a) Sublimation is the conversion of a solid (relatively high density) to a gas (much lesser density). This process yields a much greater dispersal of matter, since the molecules will occupy a much greater volume after the solid-to-gas transition. (b) Condensation is the conversion of a gas (relatively low density) to a liquid (much greater density). This process yields a much lesser dispersal of matter, since the molecules will occupy a much lesser volume after the solid-to-gas transition. (c) The process in question is dilution. The food dye molecules initially occupy a much smaller volume (the drop of dye solution) than they occupy once the process is complete (in the full glass of water). The process therefore entails a greater dispersal of matter. The process may also yield a more uniform dispersal of matter, since the initial state of the system involves two regions of different dye concentrations (high in the drop, zero in the water), and the final state of the system contains a single dye concentration throughout."
  },
  {
    "question": "Some types of minerals form balls called what?",
    "distractor3": "fistulas",
    "distractor1": "cancers",
    "distractor2": "microbes",
    "correct_answer": "nodules",
    "support": "Some types of minerals form balls called nodules. Nodules may be tiny or as big as basketballs. They contain manganese, iron, copper, and other useful minerals. As many as 500 billion tons of nodules lie on the ocean floor! However, mining them would be very costly and could be harmful to the ocean environment."
  },
  {
    "question": "In a solution what is the substance a solute dissolves in is called?",
    "distractor3": "atoms",
    "distractor1": "particles",
    "distractor2": "gas",
    "correct_answer": "solvent",
    "support": "A solution forms when one substance dissolves in another. The substance that dissolves is called the solute . The substance it dissolves in is called the solvent . For example, ocean water is a solution in which the solute is salt and the solvent is water. In this example, a solid (salt) is dissolved in a liquid (water). However, matter in any state can be the solute or solvent in a solution. Solutions may be gases, liquids, or solids. In Table below and the video at the URL below, you can learn about solutions involving other states of matter."
  },
  {
    "question": "What is the outer layer of the exoskeleton called?",
    "distractor3": "epithelium",
    "distractor1": "bristle",
    "distractor2": "epidermis",
    "correct_answer": "cuticle",
    "support": "Segmented bodies with an exoskeleton . The outer layer of the exoskeleton is called the cuticle . It is made up of two layers. The outer layer, or exocuticle , is thin, waxy, and water-resistant. The inner layer is much thicker. The exocuticle is extremely thin in many soft-bodied insects, such as caterpillars."
  },
  {
    "question": "What is the transition from solid to vapor is called?",
    "distractor3": "ionization",
    "distractor1": "vaporization",
    "distractor2": "deposition",
    "correct_answer": "sublimation",
    "support": "Sublimation is the transition from solid to vapor phase. You may have noticed that snow can disappear into thin air without a trace of liquid water, or the disappearance of ice cubes in a freezer. The reverse is also true: Frost can form on very cold windows without going through the liquid stage. A popular effect is the making of “smoke” from dry ice, which is solid carbon dioxide. Sublimation occurs because the equilibrium vapor pressure of solids is not zero. Certain air fresheners use the sublimation of a solid to inject a perfume into the room. Moth balls are a slightly toxic example of a phenol (an organic compound) that sublimates, while some solids, such as osmium tetroxide, are so toxic that they must be kept in sealed containers to prevent human exposure to their sublimation-produced vapors."
  },
  {
    "question": "While elements are represented by chemical symbols, chemical formulas represent what?",
    "distractor3": "solutions",
    "distractor1": "extracts",
    "distractor2": "pollutants",
    "correct_answer": "compounds",
    "support": "Elements are represented by chemical symbols. Examples are H for hydrogen and O for oxygen. Compounds are represented by chemical formulas . You’ve already seen the chemical formula for water. It’s H 2 O. The subscript 2 after the H shows that there are two atoms of hydrogen in a molecule of water. The O for oxygen has no subscript. When there is just one atom of an element in a molecule, no subscript is used. Table below shows some other examples of compounds and their chemical formulas."
  },
  {
    "question": "The amount of heat required to raise a single mass unit of a substance by a single temperature unit is known as what?",
    "distractor3": "solitary heat",
    "distractor1": "temperature variation",
    "distractor2": "specific gravity",
    "correct_answer": "specific heat",
    "support": "When heat flows into an object, its thermal energy increases and so does its temperature. The amount of temperature increase depends on three things: 1) how much heat was added, 2) the size of the object, and 3) the material of which the object is made. When you add the same amount of heat to the same mass of different substances, the amount of temperature increase is different. Each substance has a specific heat, which is the amount of heat necessary to raise one mass unit of that substance by one temperature unit."
  },
  {
    "question": "Haversian canals contain blood vessels and what else?",
    "distractor3": "collagen fibers",
    "distractor1": "muscle fibers",
    "distractor2": "synovial fluid",
    "correct_answer": "nerve fibers",
    "support": "Compact bone tissue is made of cylindrical osteons that are aligned such that they travel the length of the bone. Haversian canals contain blood vessels only. Haversian canals contain blood vessels and nerve fibers. Spongy tissue is found on the interior of the bone, and compact bone tissue is found on the exterior. Figure 38.37 Which of the following statements about muscle contraction is true?."
  },
  {
    "question": "What do ionic bonds form between?",
    "distractor3": "metals and organisms",
    "distractor1": "metals and carbonates",
    "distractor2": "metals and freshwaters",
    "correct_answer": "metals and nonmetals",
    "support": "Ionic bonds form only between metals and nonmetals. That’s because metals “want” to give up electrons, and nonmetals “want” to gain electrons."
  },
  {
    "question": "The interaction between atomic orbitals is greatest when they have the same what?",
    "distractor3": "fuel",
    "distractor1": "temperature",
    "distractor2": "mass",
    "correct_answer": "energy",
    "support": "The number of molecular orbitals produced is the same as the number of atomic orbitals used to create them (the law of conservation of orbitals). As the overlap between two atomic orbitals increases, the difference in energy between the resulting bonding and antibonding molecular orbitals increases. When two atomic orbitals combine to form a pair of molecular orbitals, the bonding molecular orbital is stabilized about as much as the antibonding molecular orbital is destabilized. The interaction between atomic orbitals is greatest when they have the same energy."
  },
  {
    "question": "All chemical reactions involve both reactants and what else?",
    "distractor3": "energy",
    "distractor1": "consumers",
    "distractor2": "catalysts",
    "correct_answer": "products",
    "support": "All chemical reactions involve both reactants and products. Reactants are substances that start a chemical reaction, and products are substances that are produced in the reaction."
  },
  {
    "question": "Potassium hydroxide in soap is an example of what?",
    "distractor3": "acid",
    "distractor1": "enzyme",
    "distractor2": "catalyst",
    "correct_answer": "base",
    "support": "Bases are used for a variety of purposes. For example, soaps contain bases such as potassium hydroxide (KOH). Other uses of bases can be seen in the Figure below ."
  },
  {
    "question": "What protects the pollen of seed plants and spores of seedless plants?",
    "distractor3": "chlorophyll",
    "distractor1": "cystosol",
    "distractor2": "cocklebur",
    "correct_answer": "sporopollenin",
    "support": "The spores of seedless plants and the pollen of seed plants are surrounded by thick cell walls containing a tough polymer known as sporopollenin. This substance is characterized by long chains of organic molecules related to fatty acids and carotenoids, and gives most pollen its yellow color. Sporopollenin is unusually resistant to chemical and biological degradation. Its toughness explains the existence of well-preserved fossils of pollen. Sporopollenin was once thought to be an innovation of land plants; however, the green algae Coleochaetes is now known to form spores that contain sporopollenin. Protection of the embryo is a major requirement for land plants. The vulnerable embryo must be sheltered from desiccation and other environmental hazards. In both seedless and seed plants, the female gametophyte provides nutrition, and in seed plants, the embryo is also protected as it develops into the new generation of sporophyte."
  },
  {
    "question": "One important phenomenon related to the relative strength of cohesive and adhesive forces is capillary action—the tendency of a fluid to be raised or suppressed in a narrow tube, or called this?",
    "distractor3": "pressure tube",
    "distractor1": "melting tube",
    "distractor2": "cohesive tube",
    "correct_answer": "capillary tube",
    "support": "One important phenomenon related to the relative strength of cohesive and adhesive forces is capillary action—the tendency of a fluid to be raised or suppressed in a narrow tube, or capillary tube. This action causes blood to be drawn into a small-diameter tube when the tube touches a drop. Capillary Action The tendency of a fluid to be raised or suppressed in a narrow tube, or capillary tube, is called capillary action. If a capillary tube is placed vertically into a liquid, as shown in Figure 11.34, capillary action will raise or suppress the liquid inside the tube depending on the combination of substances. The actual effect depends on the relative strength of the cohesive and adhesive forces and, thus, the contact angle θ given in the table. If θ is less than 90º , then the fluid will be raised; if θ is greater than 90º , it will be suppressed. Mercury, for example, has a very large surface tension and a large contact angle with glass. When placed in a tube, the surface of a column of mercury curves downward, somewhat like a drop. The curved surface of a fluid in a tube is called a meniscus. The tendency of surface tension is always to reduce the surface area. Surface tension thus flattens the curved liquid surface in a capillary tube. This results in a downward force in mercury and an upward force in water, as seen in Figure 11.34."
  },
  {
    "question": "Salts that are neither acidic nor basic do not affect what property of the solution when dissolved in water?",
    "distractor3": "density",
    "distractor1": "homeostasis",
    "distractor2": "saturation",
    "correct_answer": "ph",
    "support": "The simplest situation is a salt formed by combining a strong acid and a strong base. These salts are neither acidic nor basic, so they do not affect the pH of the solution when dissolved in water. For example, the ionic compound NaNO 3 could be prepared by combining the strong acid HNO 3 and the strong base NaOH. If we were to dissolve NaNO 3 in water, it would dissociate into Na + and NO 3 - ions. Neither ion is a strong enough acid or base to cause any noticeable proton transfers, so the pH of the pure water is not altered."
  },
  {
    "question": "What are the two components of all solutions?",
    "distractor3": "concentration and solvent",
    "distractor1": "sodium and solvent",
    "distractor2": "solute and cytosol",
    "correct_answer": "solute and solvent",
    "support": "All solutions have two parts: the solute and the solvent. The solute is the substance that dissolves, and the solvent is the substance that dissolves the solute. Particles of solvent pull apart particles of solute, and the solute particles spread throughout the solvent. Salt water, such as the ocean water in the Figure below , is an example of a solution. In a saltwater solution, salt is the solute and water is the solvent."
  },
  {
    "question": "Matter undergoing chemical reactions and physical changes can release or absorb heat. a change that releases heat is called what?",
    "distractor3": "biochemical process",
    "distractor1": "magnetic process",
    "distractor2": "oxidized process",
    "correct_answer": "exothermic process",
    "support": "Matter undergoing chemical reactions and physical changes can release or absorb heat. A change that releases heat is called an exothermic process. For example, the combustion reaction that occurs when using an oxyacetylene torch is an exothermic process—this process also releases energy in the form of light as evidenced by the torch’s flame (Figure 5.7). A reaction or change that absorbs heat is an endothermic process. A cold pack used to treat muscle strains provides an example of an endothermic process. When the substances in the cold pack (water and a salt like ammonium nitrate) are brought together, the resulting process absorbs heat, leading to the sensation of cold."
  },
  {
    "question": "Because optics fibers are thin, entering light may strike the inside surface at greater than the critical angle, requiring attention to what?",
    "distractor3": "wavelength",
    "distractor1": "reflective point",
    "distractor2": "electromagnetic index",
    "correct_answer": "refractive index",
    "support": "Fiber Optics: Endoscopes to Telephones Fiber optics is one application of total internal reflection that is in wide use. In communications, it is used to transmit telephone, internet, and cable TV signals. Fiber optics employs the transmission of light down fibers of plastic or glass. Because the fibers are thin, light entering one is likely to strike the inside surface at an angle greater than the critical angle and, thus, be totally reflected (See Figure 25.14. ) The index of refraction outside the fiber must be smaller than inside, a condition that is easily satisfied by coating the outside of the fiber with a material having an appropriate refractive index. In fact, most fibers have a varying refractive index to allow more light to be guided along the fiber through total internal refraction. Rays are reflected around corners as shown, making the fibers into tiny light pipes."
  },
  {
    "question": "What are atoms of the same element that differ in their numbers of neutrons called?",
    "distractor3": "opposites",
    "distractor1": "reactions",
    "distractor2": "organisms",
    "correct_answer": "isotopes",
    "support": "The first plants were probably similar to the stoneworts in Figure below . Stoneworts are green algae. Like stoneworts, the first plants were aquatic. They may have had stalks but not stems. They also may have had hair-like structures called rhizoids but not roots. The first plants probably had male and female reproductive organs and needed water to reproduce. In stoneworts, sperm need at least a thin film of moisture to swim to eggs."
  },
  {
    "question": "Practitioners of what thought all matter was composed of different proportions of four basic elements, and that if you changed the proportions of these elements, you could change the substance itself?",
    "distractor3": "phrenology",
    "distractor1": "chemistry",
    "distractor2": "biology",
    "correct_answer": "alchemy",
    "support": "Alchemy was a somewhat mystical and secretive approach to learning how to manipulate matter. Practitioners, called alchemists, thought that all matter was composed of different proportions of the four basic elements—fire, water, earth, and air—and believed that if you changed the relative proportions of these elements in a substance, you could change the substance. The long-standing attempts to “transmute” common metals into gold represented one goal of alchemy. Alchemy’s other major goal was to synthesize the philosopher’s stone, a material that could impart long life—even immortality. Alchemists used symbols to represent substances, some of which are shown in the accompanying figure. This was not done to better communicate ideas, as chemists do today, but to maintain the secrecy of alchemical knowledge, keeping others from sharing in it."
  },
  {
    "question": "What model describing atomic structure is often referred to as a planetary model?",
    "distractor3": "Pascal model",
    "distractor1": "Newton's model",
    "distractor2": "kinetic model",
    "correct_answer": "bohr model",
    "support": "According to the Bohr model, often referred to as a planetary model , the electrons encircle the nucleus of the atom in specific allowable paths called orbits. When the electron is in one of these orbits, its energy is fixed. The ground state of the hydrogen atom, where its energy is lowest, is when the electron is in the orbit that is closest to the nucleus. The orbits that are further from the nucleus are all of successively greater energy. The electron is not allowed to occupy any of the spaces in between the orbits. An everyday analogy to the Bohr model is the rungs of a ladder. As you move up or down a ladder, you can only occupy specific rungs and cannot be in the spaces in between rungs. Moving up the ladder increases your potential energy, while moving down the ladder decreases your energy."
  },
  {
    "question": "Compounds containing which element are the basis of all known life?",
    "distractor3": "hydrogen",
    "distractor1": "oxygen",
    "distractor2": "helium",
    "correct_answer": "carbon",
    "support": "Carbon has the ability to form very long chains of interconnecting C-C bonds. This property allows carbon to form the backbone of organic compounds , carbon-containing compounds, which are the basis of all known organic life. Nearly 10 million carbon-containing organic compounds are known. Types of carbon compounds in organisms include carbohydrates, lipids, proteins, and nucleic acids. The elements found in each type are listed in the table below. Elements other than carbon and hydrogen usually occur within organic compounds in smaller groups of elements called functional groups . When organic compounds react with other compounds, generally just the functional groups are involved. Therefore, functional groups generally determine the nature and functions of organic compounds."
  },
  {
    "question": "What type of rocks form when an existing rock is changed by heat or pressure?",
    "distractor3": "sediments",
    "distractor1": "Molten",
    "distractor2": "igneous",
    "correct_answer": "metamorphic",
    "support": "3. Metamorphic rocks form when an existing rock is changed by heat or pressure. The minerals in the rock change but do not melt ( Figure below ). The rock experiences these changes within the Earth."
  },
  {
    "question": "The type of bond that forms between molecules is called what?",
    "distractor3": "helium bond",
    "distractor1": "fission bond",
    "distractor2": "covalent bond",
    "correct_answer": "hydrogen bond",
    "support": "Opposites attract when it comes to charged molecules. In the case of water, the positive (hydrogen) end of one water molecule is attracted to the negative (oxygen) end of a nearby water molecule. Because of this attraction, weak bonds form between adjacent water molecules, as shown in Figure below . The type of bond that forms between molecules is called a hydrogen bond . Bonds between molecules are not as strong as bonds within molecules, but in water they are strong enough to hold together nearby molecules."
  },
  {
    "question": "Under the right conditions, what energy source can be used to eject electrons from a solid material?",
    "distractor3": "gravity",
    "distractor1": "force",
    "distractor2": "weight",
    "correct_answer": "light",
    "support": "Under the right conditions, light can be used to eject electrons from a solid material."
  },
  {
    "question": "What is the second largest class of elements?",
    "distractor3": "metalloids",
    "distractor1": "carbonates",
    "distractor2": "silicates",
    "correct_answer": "nonmetals",
    "support": "Nonmetals are elements that do not conduct electricity. They are the second largest class of elements. Find the nonmetals in Figure above . They are all the elements on the right side of the table that are color-coded green. Examples of nonmetals include helium (He), carbon (C), and oxygen (O)."
  },
  {
    "question": "What is a rock that contains important minerals called?",
    "distractor3": "copper",
    "distractor1": "carbonic",
    "distractor2": "steel",
    "correct_answer": "ore",
    "support": "A rock that contains important minerals is called an ore . The concentration of valuable minerals in an ore may be high or low."
  },
  {
    "question": "What are solids with high melting and boiling points?",
    "distractor3": "metal alloys",
    "distractor1": "magnetic compounds",
    "distractor2": "superheated compounds",
    "correct_answer": "ionic compounds",
    "support": "Ionic compounds are solids with high melting and boiling points. They are good conductors of electricity but only when dissolved in water. Their crystals are rigid and brittle."
  },
  {
    "question": "What term means the set of processes by which metals are extracted from their ores and converted to more useful forms?",
    "distractor3": "ceramics",
    "distractor1": "metamorphisis",
    "distractor2": "introversion",
    "correct_answer": "metallurgy",
    "support": "Very few of the transition metals are found in nature as free metals. Consequently, almost all metallic elements must be isolated from metal oxide or metal sulfide ores. Metallurgy is the set of processes by which metals are extracted from their ores and converted to more useful forms. Metallurgy consists of three general steps: (1) mining the ore, (2) separating and concentrating the metal or the metal-containing compound, and (3) reducing the ore to the metal. Additional processes are sometimes required to improve the mechanical properties of the metal or increase its purity. Many ores contain relatively low concentrations of the desired metal; for example, copper ores that contain even 1% Cu by mass are considered commercially useful. After an ore has been mined, the first step in processing is usually to crush it because the rate of chemical reactions increases dramatically with increased surface area. Next, one of three general strategies is used to separate and concentrate the compound(s) of interest: settling and flotation, which are based on differences in density between the desired compound and impurities; pyrometallurgy, which uses chemical reduction at high temperatures; and hydrometallurgy, which employs chemical or electrochemical reduction of an aqueous solution of the metal. Other methods that take advantage of unusual physical or chemical properties of a particular compound may also be used. For example, crystals of magnetite (Fe3O4) are tiny but rather powerful magnets; in fact, magnetite (also known as lodestone) was used to make the first compasses in China during the first century BC. If a crushed ore that contains magnetite is passed through a powerful magnet, the Fe3O4 particles are attracted to the poles of the magnet, allowing them to be easily separated from other minerals."
  },
  {
    "question": "What is the most direct way of recovering a metal from its ores?",
    "distractor3": "osmosis",
    "distractor1": "drilling",
    "distractor2": "molecules",
    "correct_answer": "electrolysis",
    "support": "Electrolysis is the most direct way of recovering a metal from its ores. However, the Na (aq)/Na(s), 2+."
  },
  {
    "question": "What do metals start out as?",
    "distractor3": "nickel",
    "distractor1": "Metal molecules",
    "distractor2": "aluminum",
    "correct_answer": "ore",
    "support": "Minerals have to be removed from the ground and made into the products. All the metals we use start out as an ore. Mining the ore is just the first step. Next, the ore must be separated from the rest of the rock that is mined. Then, the minerals need to be separated out of the ore."
  },
  {
    "question": "The evaporative loss of the most energetic water molecules does what to a surface?",
    "distractor3": "charges it",
    "distractor1": "heats it",
    "distractor2": "vents it",
    "correct_answer": "cools it",
    "support": ""
  },
  {
    "question": "Does lava flow quickly or slowly when thick?",
    "distractor3": "steadily",
    "distractor1": "quickly",
    "distractor2": "rapidly",
    "correct_answer": "slowly",
    "support": "When lava is thick, it flows slowly. If thick lava makes it to the surface, it cannot flow far from the vent. It often stays right in the middle of a crater at the top of a volcano. Here the lava creates a large, round lava dome ( Figure below )."
  },
  {
    "question": "What is the term for viscous magmas that are high in silica and tend to stay below the surface or erupt explosively?",
    "distractor3": "combustible magmas",
    "distractor1": "sedimentary magmas",
    "distractor2": "compacted magmas",
    "correct_answer": "felsic magmas",
    "support": "The chemistry of a magma determines the type of igneous rock it forms. The chemistry also determines how the magma moves. The higher the amount of silica in the magma, the higher the viscosity. Viscosity is a liquid's resistance to flow. Viscous magmas tend to stay below the surface or erupt explosively. These are felsic magmas, which are high in silica. When magma is fluid and runny, it is not viscous. This magma often reaches the surface by flowing out in rivers of lava. These are low-silica mafic magmas."
  },
  {
    "question": "What type of bonds are formed between atoms sharing electrons?",
    "distractor3": "ionic",
    "distractor1": "neutron bonds",
    "distractor2": "hydroxyl",
    "correct_answer": "covalent",
    "support": "Covalent bonds are formed between atoms sharing electrons."
  },
  {
    "question": "What type of particle collides with an atom of u-235 during the basic nuclear fission process?",
    "distractor3": "a proton",
    "distractor1": "an electron",
    "distractor2": "a nuclei",
    "correct_answer": "a neutron",
    "support": "The example above illustrates the basic nuclear fission process. A neutron (generally produced by some controlled process, not usually a natural event) collides with an atom of U-235. Momentarily, a U-236 atom forms which then splits into two smaller atoms (Kr-93 and Ba-141) in the diagram. This process results in the release of three new neutrons, which can then initiate fission reactions with more atoms. We will see later how this propagation of neutrons can be employed in a reactor for the generation of electricity."
  },
  {
    "question": "What color is phosphate mineral turquoise?",
    "distractor3": "purple",
    "distractor1": "white",
    "distractor2": "green",
    "correct_answer": "blue",
    "support": "Turquoise is a phosphate mineral with a beautiful blue color. The stone is not as rare as some minerals and is commonly used for jewelry."
  },
  {
    "question": "Soap acts as what kind of agent between grease and water?",
    "distractor3": "sterilizing",
    "distractor1": "lubricating",
    "distractor2": "codifying",
    "correct_answer": "emulsifying",
    "support": "Butter and mayonnaise are examples of a class of colloids called emulsions . An emulsion is a colloidal dispersion of a liquid in either a liquid or a solid. A stable emulsion requires an emulsifying agent to be present. Mayonnaise is made in part of oil and vinegar. Since oil is nonpolar and vinegar is an aqueous solution and polar, the two do not mix and would quickly separate into layers. However, the addition of egg yolk causes the mixture to become stable and not separate. Egg yolk is capable of interacting with both the polar vinegar and the nonpolar oil. The egg yolk is called the emulsifying agent. Soap acts as an emulsifying agent between grease and water. Grease cannot be simply rinsed off your hands or another surface because it is insoluble. However, the soap stabilizes a grease-water mixture because one end of a soap molecule is polar and the other end is nonpolar. This allows the grease to be removed from your hands or your clothing by washing with soapy water."
  },
  {
    "question": "The cell membrane consists of two layers of what?",
    "distractor3": "filaments",
    "distractor1": "chlorophyll",
    "distractor2": "epidermis",
    "correct_answer": "phospholipids",
    "support": "The cell membrane consists of two layers of phospholipids. Transport proteins are embedded in the layers. The movement of substances across the cell membrane may be by passive or active transport."
  },
  {
    "question": "What is the energy that matter possesses because of its location or structure?",
    "distractor3": "thermal energy",
    "distractor1": "kinetic energy",
    "distractor2": "mechanical energy",
    "correct_answer": "potential energy",
    "support": ""
  },
  {
    "question": "What kind of a process is corrosion?",
    "distractor3": "electromagnetic",
    "distractor1": "electrolysis",
    "distractor2": "oxidation",
    "correct_answer": "galvanic",
    "support": "Note the Pattern Corrosion is a galvanic process. Under ambient conditions, the oxidation of most metals is thermodynamically spontaneous, with the notable exception of gold and platinum. Hence it is actually somewhat surprising that any metals are useful at all in Earth’s moist, oxygen-rich atmosphere. Some metals, however, are resistant to corrosion for kinetic reasons. For example, aluminum in soft-drink cans and airplanes is protected by a thin coating of metal oxide that forms on the surface of the metal and acts as an impenetrable barrier that prevents further destruction. Aluminum cans also have a thin plastic layer to prevent reaction of the oxide with acid in the soft drink. Chromium, magnesium, and nickel also form protective oxide films. Stainless steels are remarkably resistant to corrosion because they usually contain a significant proportion of chromium, nickel, or both. In contrast to these metals, when iron corrodes, it forms a red-brown hydrated metal oxide (Fe2O3·xH2O), commonly known as rust, that does not provide a tight protective film (Figure 19.17 \"Rust, the Result of Corrosion of."
  },
  {
    "question": "Monomers of condensation polymers must contain how many functional groups so that each monomer can link up with two other monomers?",
    "distractor3": "one",
    "distractor1": "three",
    "distractor2": "four",
    "correct_answer": "two",
    "support": "A condensation polymer is a polymer formed by condensation reactions. Monomers of condensation polymers must contain two functional groups so that each monomer can link up with two other monomers. One type of condensation polymer is called a polyamide. An amide is characterized by the functional group shown below wherein the carbon of a carbonyl group is bonded to the nitrogen of an amine."
  },
  {
    "question": "What is the difference between oils and fats at room temperature?",
    "distractor3": "liquid and gas states",
    "distractor1": "solid and gas states",
    "distractor2": "saturated and unsaturated",
    "correct_answer": "liquid and solid states",
    "support": "A lipid is a member of a class of water-insoluble compounds that includes oils, fats, and waxes. Oils and fats are based on the same general structure, but fats are solids at room temperature, while oils are liquids. Butter is an example of a fat and is derived from animals. Some oils include olive oil and canola oil, which are obtained from plants. Lipids are an essential part of a healthy diet, though excess dietary fat can be harmful. Lipids store energy in the body and are also needed to keep cell membranes healthy."
  },
  {
    "question": "Silk and cotton are examples of what kind of fiber?",
    "distractor3": "simple",
    "distractor1": "pure",
    "distractor2": "artificial",
    "correct_answer": "natural",
    "support": "The fibers that compose the materials for our clothes are either natural or human-made. Silk and cotton would be examples of natural fibers. Silk is produced by the silkworm and cotton is grown as a plant. Human-made fabrics include nylon, orlon, and a number of other polymers. These materials are made from hydrocarbons found in petroleum products. Synthetic polymers are also used in shoes, raingear, and camping items. The synthetic fabrics tend to be lighter than the natural ones and can be treated to make them more water-resistant and durable."
  },
  {
    "question": "The chains in cellulose stack in parallel rows held together by hydrogen bonds between which groups?",
    "distractor3": "soda groups",
    "distractor1": "disc groups",
    "distractor2": "carbon groups",
    "correct_answer": "hydroxl groups",
    "support": "that produce a coiled structure. The glucose units in cellulose, in contrast, are linked to give long, unbranched chains. The chains in cellulose stack in parallel rows held together by hydrogen bonds between hydroxyl groups. This arrangement produces a rigid structure that is insoluble in water. Figure 24.22 The Polysaccharides Starch and Cellulose."
  },
  {
    "question": "Which is a more reliable trait or measure to identify minerals?",
    "distractor3": "weight",
    "distractor1": "color",
    "distractor2": "shape",
    "correct_answer": "streak",
    "support": "Streak is more reliable than color to identify minerals. The color of a mineral may vary. Streak does not vary. Also, different minerals may be the same color, but they may have a different color streak. For example, samples of hematite and galena can both be dark gray. They can be told apart because hematite has a red streak and galena has a gray streak."
  },
  {
    "question": "What is the name of the molecule which has one carbon and four hydrogen atoms?",
    "distractor3": "carbon monoxide",
    "distractor1": "carbohydrate",
    "distractor2": "sulfur",
    "correct_answer": "methane",
    "support": "Hydrocarbons are made of carbon and hydrogen atoms. This molecule with one carbon and four hydrogen atoms is methane."
  },
  {
    "question": "Magnets have a \"north\" and a \"south\" what?",
    "distractor3": "temperature",
    "distractor1": "arch",
    "distractor2": "grid",
    "correct_answer": "pole",
    "support": "Figure 22.3 Magnets come in various shapes, sizes, and strengths. All have both a north pole and a south pole. There is never an isolated pole (a monopole)."
  },
  {
    "question": "What kind of diffusion do small hydrophobic molecules squeeze through lipid molecules?",
    "distractor3": "complex",
    "distractor1": "difficult",
    "distractor2": "slippery",
    "correct_answer": "simple",
    "support": "Problems can occur with red blood cells, white blood cells, platelets, and other parts of the blood. Many blood disorders are genetic, meaning they are inherited from a parent. Some blood diseases are caused by not getting enough of a certain nutrient, while others are cancers of the blood."
  },
  {
    "question": "What is the term for materials that have both a defined shape and a defined volume?",
    "distractor3": "gases",
    "distractor1": "liquids",
    "distractor2": "matter",
    "correct_answer": "solids",
    "support": "Solids are materials that have both a defined shape and a defined volume. They do not take on the shape of their container, as liquids and gases do. Solids can be either amorphous or crystalline. Amorphous solids (such as glass) do not have a well organized three-dimensional arrangement of molecules or atoms, so they lack a high level of order. On the other hand, crystalline solids display a highly ordered and predictable three-dimensional structure. In this section we will discuss the different types of crystalline solids."
  },
  {
    "question": "What are chromosomes made of?",
    "distractor3": "muscle tissue",
    "distractor1": "amino acids",
    "distractor2": "sperm and proteins",
    "correct_answer": "dna and proteins",
    "support": "Chromosomes are coiled structures made of DNA and proteins. Chromosomes are the form of the genetic material of a cell during cell division. It is this coiled structure that ensures proper segregation of the chromosomes during cell division. During other phases of the cell cycle, DNA is not coiled into chromosomes. Instead, it exists as a grainy material called chromatin ."
  },
  {
    "question": "In relation to electrical current, what property will a narrow wire have more of than a wide wire?",
    "distractor3": "current",
    "distractor1": "voltage",
    "distractor2": "wattage",
    "correct_answer": "resistance",
    "support": "A wide wire has less resistance than a narrow wire of the same material. Electricity flowing through a wire is like water flowing through a hose. More water can flow through a wide hose than a narrow hose. In a similar way, more current can flow through a wide wire than a narrow wire."
  },
  {
    "question": "When do gases and liquids become solids?",
    "distractor3": "at high temperatures",
    "distractor1": "at relative temperatures",
    "distractor2": "at hot temperatures",
    "correct_answer": "at low temperatures",
    "support": "We tend to think of solids as those materials that are solid at room temperature. However, all materials have melting points of some sort. Gases become solids at extremely low temperatures, and liquids will also become solid if the temperature is low enough. The Table below gives the melting points of some common materials."
  },
  {
    "question": "Railroad tracks and roadways can buckle on hot days if they lack sufficient what?",
    "distractor3": "attraction joints",
    "distractor1": "cartilaginous joints",
    "distractor2": "contraction joints",
    "correct_answer": "expansion joints",
    "support": "Forces and pressures created by thermal stress are typically as great as that in the example above. Railroad tracks and roadways can buckle on hot days if they lack sufficient expansion joints. (See Figure 13.14. ) Power lines sag more in the summer than in the winter, and will snap in cold weather if there is insufficient slack. Cracks open and close in plaster walls as a house warms and cools. Glass cooking pans will crack if cooled rapidly or unevenly, because of differential contraction and the."
  },
  {
    "question": "What do you call materials able to conduct electricity with 100% efficiency, meaning that no energy is lost during the electrical transmission?",
    "distractor3": "super-insulators",
    "distractor1": "poor conductors",
    "distractor2": "electromagnets",
    "correct_answer": "superconductors",
    "support": "Many chemists are currently working in the field of superconductivity. Superconductors are materials that are able to conduct electricity with 100% efficiency, meaning that no energy is lost during the electrical transmission, as happens with conventional conducting materials like copper cable. The challenge is to design materials that can act as superconductors at normal temperatures, as opposed to only being able to superconduct at very low temperatures."
  },
  {
    "question": "Corrosion is usually defined as the degradation of metals due to what?",
    "distractor3": "oscillatory process",
    "distractor1": "crystalline process",
    "distractor2": "nuclear process",
    "correct_answer": "electrochemical process",
    "support": "Corrosion is usually defined as the degradation of metals due to an electrochemical process. The formation of rust on iron, tarnish on silver, and the blue-green patina that develops on copper are all examples of corrosion. The total cost of corrosion in the United States is significant, with estimates in excess of half a trillion dollars a year."
  },
  {
    "question": "Properties of matter can be considered physical or?",
    "distractor3": "liquid",
    "distractor1": "gas",
    "distractor2": "mineral",
    "correct_answer": "chemical",
    "support": ""
  },
  {
    "question": "What is the name of the complex mixture that consists of water, proteins, fats, carbohydrates, and minerals?",
    "distractor3": "sperm",
    "distractor1": "plasma",
    "distractor2": "blood",
    "correct_answer": "milk",
    "support": "Milk is a complex mixture of water, proteins, fats, carbohydrates, and minerals. While the minerals and carbohydrates are water-soluble, the fats and some of the proteins do not dissolve but are held in suspension."
  },
  {
    "question": "What is the separation of ions that occurs when a solid ionic compound dissolves?",
    "distractor3": "inflammation",
    "distractor1": "combustion",
    "distractor2": "decomposition",
    "correct_answer": "dissociation",
    "support": "Dissociation is the separation of ions that occurs when a solid ionic compound dissolves."
  },
  {
    "question": "What bonding is formed in polar amino acid side chains?",
    "distractor3": "helium bonding",
    "distractor1": "calcium bonding",
    "distractor2": "carbon bonding",
    "correct_answer": "hydrogen bonding",
    "support": "Hydrogen bonding. Hydrogen bonding forms between a highly electronegative oxygen atom or a nitrogen atom and a hydrogen atom attached to another oxygen atom or a nitrogen atom, such as those found in polar amino acid side chains. Hydrogen bonding (as well as ionic attractions) is extremely important in both the intra- and intermolecular interactions of proteins (part (b) of http://catalog. flatworldknowledge. com/bookhub/reader/2547 - gob-ch18_s04_s01_f05). Disulfide linkages. Two cysteine amino acid units may be brought close together as the protein molecule folds. Subsequent oxidation and linkage of the sulfur atoms in the highly reactive sulfhydryl (SH) groups leads to the formation of cystine (part (c) ofhttp://catalog. flatworldknowledge. com/bookhub/reader/2547 - gob-ch18_s04_s01_f05). Intrachain disulfide linkages are found in many proteins, including insulin (yellow bars in http://catalog. flatworldknowledge. com/bookhub/reader/2547 - gob-ch18_s04_s01_f01) and have a strong stabilizing effect on the tertiary structure."
  },
  {
    "question": "Solutions of nonelectrolytes such as ethanol do not contain dissolved ions and cannot conduct what?",
    "distractor3": "light",
    "distractor1": "sound",
    "distractor2": "current",
    "correct_answer": "electricity",
    "support": "Figure 11.7 Solutions of nonelectrolytes such as ethanol do not contain dissolved ions and cannot conduct electricity. Solutions of electrolytes contain ions that permit the passage of electricity. The conductivity of an electrolyte solution is related to the strength of the electrolyte."
  },
  {
    "question": "What branch of science is concerned with matter and the changes that it can undergo?",
    "distractor3": "biology",
    "distractor1": "geology",
    "distractor2": "physiology",
    "correct_answer": "chemistry",
    "support": "Chemistry is the study of matter and the changes that matter can undergo."
  },
  {
    "question": "Oxygen is an element in what form of matter?",
    "distractor3": "plasma",
    "distractor1": "liquid",
    "distractor2": "solid",
    "correct_answer": "gas",
    "support": "Physical properties include the state of matter and its color and odor. For example, oxygen is a colorless, odorless gas. Chlorine is a greenish gas with a strong, sharp odor. Other physical properties include hardness, freezing and boiling points, the ability to dissolve in other substances, and the ability to conduct heat or electricity. These properties are demonstrated in Figure below . Can you think of other physical properties?."
  },
  {
    "question": "What type of molecules help the plasma membrane keep its shape?",
    "distractor3": "metabolic",
    "distractor1": "proteins",
    "distractor2": "magnesium",
    "correct_answer": "cholesterol",
    "support": "The plasma membrane contains molecules other than phospholipids, primarily other lipids and proteins. The green molecules in Figure below , for example, are the lipid cholesterol. Molecules of cholesterol help the plasma membrane keep its shape. Many of the proteins in the plasma membrane assist other substances in crossing the membrane."
  },
  {
    "question": "What force occurs because no surface is perfectly smooth?",
    "distractor3": "tension",
    "distractor1": "vibration",
    "distractor2": "gravity",
    "correct_answer": "friction",
    "support": "Friction occurs because no surface is perfectly smooth."
  },
  {
    "question": "Free fatty acids are carboxylic acids that contain long chains of what?",
    "distractor3": "particles",
    "distractor1": "vapors",
    "distractor2": "lipds",
    "correct_answer": "hydrocarbons",
    "support": "In the Figure below , we see the structures of some common classes of lipids. Free fatty acids are carboxylic acids that contain long hydrocarbon chains. Saturated fatty acids are alkanes with a single carboxylic acid, whereas unsaturated fatty acids contain one or more C-C double bonds. Fatty acids often form esters with one of the alcohol functional groups on glycerol , a three carbon chain in which each carbon is bonded to one OH group. Triglycerides are common structures, in which all three of these OH groups are esterified with a fatty acid. The three fatty acids in a triglyceride may be the same or different. Another common structure is a phospholipid, in which two of the alcohols in glycerol form esters with fatty acids, and the third is connected to a very polar phosphorus-containing group."
  },
  {
    "question": "After coming apart from the crystal, the individual ions are then surrounded by solvent particles in a process called what?",
    "distractor3": "hydrolysis",
    "distractor1": "osmosis",
    "distractor2": "ionization",
    "correct_answer": "solvation",
    "support": "After coming apart from the crystal, the individual ions are then surrounded by solvent particles in a process called solvation . Note that the individual Na + ions are surrounded by water molecules with the oxygen atom oriented near the positive ion. Likewise, the chloride ions are surrounded by water molecules with the opposite orientation. Hydration is the process of solute particles being surrounded by water molecules arranged in a specific manner. Hydration helps to stabilize aqueous solutions by preventing the positive and negative ions from coming back together and forming a precipitate."
  },
  {
    "question": "A battery is a multiple connection of what kind of cells?",
    "distractor3": "localweather cells",
    "distractor1": "cabri cells",
    "distractor2": "organic cells",
    "correct_answer": "voltaic cells",
    "support": "Multiple Voltage Sources There are two voltage sources when a battery charger is used. Voltage sources connected in series are relatively simple. When voltage sources are in series, their internal resistances add and their emfs add algebraically. (See Figure 21.15. ) Series connections of voltage sources are common—for example, in flashlights, toys, and other appliances. Usually, the cells are in series in order to produce a larger total emf. But if the cells oppose one another, such as when one is put into an appliance backward, the total emf is less, since it is the algebraic sum of the individual emfs. A battery is a multiple connection of voltaic cells, as shown in Figure 21.16. The disadvantage of series connections of cells is that their internal resistances add. One of the authors once owned a 1957 MGA that had two 6-V batteries in series, rather than a single 12-V battery. This arrangement produced a large internal resistance that caused him many problems in starting the engine."
  },
  {
    "question": "Highly reactive nonmetals, which only accept electrons and do not give them up, make poor what?",
    "distractor3": "electromagnets",
    "distractor1": "alloys",
    "distractor2": "insulators",
    "correct_answer": "electricity conductors",
    "support": "Some nonmetals, such as bromine, have an outer energy level that is almost full. They \"want\" to gain electrons so they will have a full outer energy level. As a result, these nonmetals are very reactive. Because they only accept electrons and do not give them up, they do not conduct electricity."
  },
  {
    "question": "What compounds form crystals instead of molecules?",
    "distractor3": "magnetic compounds",
    "distractor1": "metallic compounds",
    "distractor2": "soluble compounds",
    "correct_answer": "ionic compounds",
    "support": "Ionic compounds form crystals instead of molecules. Ionic bonds are strong and the crystals are rigid. As a result, ionic compounds are brittle solids with high melting and boiling points. In the liquid state or dissolved in water, ionic compounds are good conductors of electricity."
  },
  {
    "question": "The three units of kpa, atm or mmhg commonly measure what?",
    "distractor3": "energy",
    "distractor1": "resistance",
    "distractor2": "weight",
    "correct_answer": "pressure",
    "support": "Bone: Christopher Auyeung; Tonsils: User:Klem/Wikimedia Commons; Spleen: Henry Gray; Thymus: User:LearnAnatomy/Wikipedia. Each lymph organ has a different job in the immune system . Bone: CC-BY-NC-SA 3.0; Tonsils and Thymus: CC-BY 3.0; Spleen: Public Domain."
  },
  {
    "question": "What is the third class of elements after metals and nonmetals?",
    "distractor3": "noble gases",
    "distractor1": "halogens",
    "distractor2": "synthetics",
    "correct_answer": "metalloids",
    "support": "Elements in different groups are lumped together in one of three classes, depending on their properties. The classes are metals, nonmetals, and metalloids. Knowing the class of an element lets you predict many of its properties. The video at the URL below is a good introduction to the classes."
  },
  {
    "question": "A sample of matter that has the same physical and chemical properties throughout itself is known as what?",
    "distractor3": "molecule",
    "distractor1": "antimatter",
    "distractor2": "essence",
    "correct_answer": "substance",
    "support": "A sample of matter that has the same physical and chemical properties throughout is called a substance. Sometimes the phrase pure substance is used, but the word pure isn’t needed. The definition of the term substance is an example of how chemistry has a specific definition for a word that is used in everyday language with a different, vaguer definition. Here, we will use the term substance with its strict chemical definition. Chemistry recognizes two different types of substances: elements and compounds. An element is the simplest type of chemical substance; it cannot be broken down into simpler chemical substances by ordinary chemical means. There are about 115 elements known to science, of which 80 are stable. (The other elements are radioactive, a condition we will consider in Chapter 15 \"Nuclear Chemistry\". ) Each element has its own unique set of physical and chemical properties. Examples of elements include iron, carbon, and gold."
  },
  {
    "question": "What element is present in all organic molecules?",
    "distractor3": "hydrogen",
    "distractor1": "oxygen",
    "distractor2": "sodium",
    "correct_answer": "carbon",
    "support": "The Carbon Cycle Carbon is the fourth most abundant element in living organisms. Carbon is present in all organic molecules, and its role in the structure of macromolecules is of primary importance to living organisms. Carbon compounds contain energy, and many of these compounds from plants and algae have remained stored as fossilized carbon, which humans use as fuel. Since the 1800s, the use of fossil fuels has accelerated. As global demand for Earth’s limited fossil fuel supplies has risen since the beginning of the Industrial Revolution, the amount of carbon dioxide in our atmosphere has increased as the fuels are burned. This increase in carbon dioxide has been associated with climate change and is a major environmental concern worldwide."
  },
  {
    "question": "Hydrogen-based fuel cells were and are used to provide what for manned space vehicles?",
    "distractor3": "gravity",
    "distractor1": "light",
    "distractor2": "magnetism",
    "correct_answer": "electricity",
    "support": "Hydrogen-based fuel cells were and are used to provide electricity for manned space vehicles, partly because their only chemical product is water, which could be used for drinking. However, there has been a recent resurgence in interest in fuel cells because of their potential use in electric cars. Most electric cars run on conventional batteries, which can be very heavy and expensive to replace. It is thought that fuel cells, rather than conventional batteries, might be better sources of electricity for automobiles. Several current barriers to fuel cell use in electric cars include capacity, cost, and overall energy efficiency. The 2008 Honda FCX, the first production model of a vehicle powered with a fuel cell, can hold 4.1 kg (just under 9 lb) of highly pressured H2 gas and has a range of 450 km (280 mi). It costs about $120,000–$140,000 to build, making the vehicle beyond the ability of most people to own. Finally, it always requires more energy to produce elemental hydrogen as a fuel than can be extracted from hydrogen as a fuel. As such, hydrogen is described as an energy carrier (like electricity) rather than an energy source (like oil and gas). This distinction points out a fundamental argument against fuel cells as a “better” power source."
  },
  {
    "question": "What analytical technique, using stained gel, can separate dna fragments or rna molecules and proteins?",
    "distractor3": "static electrophoresis",
    "distractor1": "microwave electrophoresis",
    "distractor2": "surface electrophoresis",
    "correct_answer": "gel electrophoresis",
    "support": "Gel electrophoresis is an analytical technique used to separate DNA fragments by size and charge. Notice in Figure below that the \"gels\" are rectangular in shape. The gels are made of a gelatin-like material of either agarose or polyacrylamide. An electric field, with a positive charge applied at one end of the gel, and a negative charge at the other end, forces the fragments to migrate through the gel. DNA molecules migrate from negative to positive charges due to the net negative charge of the phosphate groups in the DNA backbone. Longer molecules migrate more slowly through the gel matrix. After the separation is completed, DNA fragments of different lengths can be visualized using a fluorescent dye specific for DNA, such as ethidium bromide. The resulting stained gel shows bands correspond to DNA molecules of different lengths, which also correspond to different molecular weights. Band size is usually determined by comparison to DNA ladders containing DNA fragments of known length. Gel electrophoresis can also be used to separate RNA molecules and proteins."
  },
  {
    "question": "What is the transfer of heat by physical contact?",
    "distractor3": "diffusion",
    "distractor1": "oxidation",
    "distractor2": "inhibition",
    "correct_answer": "conduction",
    "support": "Heat can be transferred in three ways, through conduction, convection, and radiation. Conduction is the transfer of heat by physical contact. Heat flows form the hotter object to the cooler object. Convection is heat transfer by an intermediate substance (for example air or water). Your oven (often properly called the ‘convection oven’) works by heating up the air and then the air heats up your food. Radiation is the release of heat (and thus the lowering of its internal energy) by releasing electromagnetic waves. The hotter the object the higher the frequency of the light emitted. When you look at a fire the blue flames our hotter than the red flames because blue has a higher frequency than red."
  },
  {
    "question": "What term describes the distance between two corresponding points on adjacent waves?",
    "distractor3": "variation",
    "distractor1": "frequency",
    "distractor2": "threshold",
    "correct_answer": "wavelength",
    "support": "Another important measure of wave size is wavelength. Wavelength is the distance between two corresponding points on adjacent waves (see Figure above ). Wavelength can be measured as the distance between two adjacent crests of a transverse wave or two adjacent compressions of a longitudinal wave. It is usually measured in meters. Wavelength is related to the energy of a wave. Short-wavelength waves have more energy than long-wavelength waves of the same amplitude. You can see examples of waves with shorter and longer wavelengths in Figure below ."
  },
  {
    "question": "What bond is the force of attraction that holds together two atoms that share a pair of valence electrons?",
    "distractor3": "metallic",
    "distractor1": "polar",
    "distractor2": "hydrogen",
    "correct_answer": "covalent",
    "support": "A covalent bond is the force of attraction that holds together two atoms that share a pair of valence electrons. Covalent bonds form only between atoms of nonmetals."
  },
  {
    "question": "What acids are the structural components of many lipids and may be saturated or unsaturated?",
    "distractor3": "carbonic acids",
    "distractor1": "fundamental acids",
    "distractor2": "ionic acids",
    "correct_answer": "fatty acids",
    "support": "Fatty acids are carboxylic acids that are the structural components of many lipids. They may be saturated or unsaturated."
  },
  {
    "question": "What happens when ionic compounds are dissolved in water?",
    "distractor3": "deflect electricity",
    "distractor1": "magnetize electricity",
    "distractor2": "repel electricity",
    "correct_answer": "conduct electricity",
    "support": "Ionic compounds conduct electricity when dissolved in water."
  },
  {
    "question": "A fuel cell is a galvanic cell that requires a constant external supply of what?",
    "distractor3": "complexes",
    "distractor1": "generators",
    "distractor2": "electricity",
    "correct_answer": "reactants",
    "support": "Fuel Cells A fuel cell is a galvanic cell that requires a constant external supply of reactants because the products of the reaction are continuously removed. Unlike a battery, it does not store chemical or electrical energy; a fuel cell allows electrical energy to be extracted directly from a chemical reaction. In principle, this should be a more efficient process than, for example, burning the fuel to drive an internal combustion engine that turns a generator, which is typically less than 40% efficient, and in fact, the efficiency of a fuel cell is generally between 40% and 60%. Unfortunately, significant cost and reliability problems have hindered the wide-scale adoption of fuel cells. In practice, their use has been restricted to applications in which mass may be a significant cost factor, such as US manned space vehicles. These space vehicles use a hydrogen/oxygen fuel cell that requires a continuous input of H2(g) and O2(g), as illustrated in Figure 19.16 \"A Hydrogen Fuel Cell Produces Electrical Energy Directly from a Chemical Reaction\". The electrode reactions are as follows: Equation 19.93."
  },
  {
    "question": "A vapor light produces visible light by what process?",
    "distractor3": "Solar Energy",
    "distractor1": "solutes",
    "distractor2": "luminescent",
    "correct_answer": "electroluminescence",
    "support": "A vapor light produces visible light by electroluminescence. The bulb contains a small amount of solid sodium or mercury as well as a mixture of neon and argon gases. When an electric current passes through the gases, it causes the solid sodium or mercury to change to a gas and emit visible light. Sodium vapor lights, like these streetlights, produce yellowish light. Mercury vapor lights produce bluish light. Vapor lights are very bright and energy efficient. The bulbs are also long lasting."
  },
  {
    "question": "Spongy bone is found inside bones and is lighter and less dense than compact bone because it is what?",
    "distractor3": "fibrous",
    "distractor1": "amorphous",
    "distractor2": "pliable",
    "correct_answer": "porous",
    "support": "Spongy bone is found inside bones and is lighter and less dense than compact bone. This is because spongy bone is porous."
  },
  {
    "question": "What element is the most abundant in the universe?",
    "distractor3": "helium",
    "distractor1": "oxygen",
    "distractor2": "carbon",
    "correct_answer": "hydrogen",
    "support": "Hydrogen is the most abundant element in the universe. The sun and other stars are composed largely of hydrogen. Astronomers estimate that 90% of the atoms in the universe are hydrogen atoms. Hydrogen is a component of more compounds than any other element. Water is the most abundant compound of hydrogen found on earth. Hydrogen is an important part of petroleum, many minerals, cellulose and starch, sugar, fats, oils, alcohols, acids, and thousands of other substances. At ordinary temperatures, hydrogen is a colorless, odorless, tasteless, and nonpoisonous gas consisting of the diatomic molecule H2. Hydrogen is composed of three isotopes, and unlike other elements, these isotopes have different names and chemical symbols: protium, 1H, deuterium, 2H (or “D”), and tritium 3H (or “T”). In a naturally occurring sample of hydrogen, there is one atom of deuterium for every 7000 H atoms and one atom of radioactive tritium for every 1018 H atoms. The chemical properties of the different isotopes are very similar because they have identical electron structures, but they differ in some physical properties because of their differing atomic masses. Elemental deuterium and tritium have lower vapor pressure than ordinary hydrogen. Consequently, when liquid hydrogen evaporates, the heavier isotopes are concentrated in the last portions to evaporate. Electrolysis of heavy water, D2O, yields deuterium. Most tritium originates from nuclear reactions."
  },
  {
    "question": "What substance, which forms igneous rock, flows out in rivers of lava when it reaches the surface?",
    "distractor3": "fertilizer",
    "distractor1": "granite",
    "distractor2": "soil",
    "correct_answer": "magma",
    "support": "The chemistry of a magma determines the type of igneous rock it forms. The chemistry also determines how the magma moves. Thicker magmas tend to stay below the surface or erupt explosively. When magma is fluid and runny, it often reaches the surface by flowing out in rivers of lava."
  },
  {
    "question": "What is the electron domain geometry of ammonia?",
    "distractor3": "neurons",
    "distractor1": "membranes",
    "distractor2": "atoms",
    "correct_answer": "tetrahedral",
    "support": "Another example of sp 3 hybridization occurs in the ammonia (NH 3 ) molecule. The electron domain geometry of ammonia is also tetrahedral, meaning that there are four groups of electrons around the central nitrogen atom. Unlike methane, however, one of those electron groups is a lone pair. The resulting molecular geometry is trigonal pyramidal. Just as in the carbon atom, the hybridization process starts as a promotion of a 2s electron to a 2p orbital, followed by hybridization to form a set of four sp 3 hybrids. In this case, one of the hybrid orbitals already contains a pair of electrons, leaving only three half-filled orbitals available to form covalent bonds with three hydrogen atoms."
  },
  {
    "question": "What is a large molecule with many repeating units?",
    "distractor3": "plasma",
    "distractor1": "cells",
    "distractor2": "supermolecule",
    "correct_answer": "polymer",
    "support": "Starches are complex carbohydrates. They are polymers of glucose. A polymer is a large molecule that consists of many smaller, repeating molecules, called monomers. The monomers are joined together by covalent bonds. Starches contain hundreds of glucose monomers. Plants make starches to store extra glucose. Consumers get starches by eating plants. Common sources of starches in the human diet are pictured in the Figure below . Our digestive system breaks down starches to sugar, which our cells use for energy."
  },
  {
    "question": "Do changes to rocks happen quickly or slowly?",
    "distractor3": "slowly then quickly",
    "distractor1": "quickly then slowly",
    "distractor2": "quickly",
    "correct_answer": "slowly",
    "support": "All rocks on Earth change, but these changes usually happen very slowly. Some changes happen below Earth’s surface. Some changes happen above ground. These changes are all part of the rock cycle. The rock cycle describes each of the main types of rocks, how they form and how they change. Figure below shows how the three main rock types are related to each other. The arrows within the circle show how one type of rock may change to rock of another type. For example, igneous rock may break down into small pieces of sediment and become sedimentary rock. Igneous rock may be buried within the Earth and become metamorphic rock. Igneous rock may also change back to molten material and re-cool into a new igneous rock."
  },
  {
    "question": "What absorbs, scatters, or reflects most incoming solar radiation in the atmosphere?",
    "distractor3": "coulds and minerals",
    "distractor1": "clouds and sand",
    "distractor2": "ice and dust",
    "correct_answer": "clouds and dust",
    "support": ""
  },
  {
    "question": "What is defined by its sequence of nucleotides?",
    "distractor3": "amino acids",
    "distractor1": "structural acids",
    "distractor2": "proteins acids",
    "correct_answer": "nucleic acids",
    "support": "Like proteins, nucleic acids have a primary structure that is defined as the sequence of their nucleotides. Unlike proteins, which have 20 different kinds of amino acids, there are only 4 different kinds of nucleotides in nucleic acids. For amino acid sequences in proteins, the convention is to write the amino acids in order starting with the Nterminal amino acid. In writing nucleotide sequences for nucleic acids, the convention is to write the nucleotides (usually using the one-letter abbreviations for the bases, shown in Figure 19.5 \"Structure of a Segment of DNA\") starting with the nucleotide having a free phosphate group, which is known as the 5′ end, and indicate the nucleotides in order. For DNA, a lowercase d is often written in front of the sequence to indicate that the monomers are deoxyribonucleotides. The final nucleotide has a free OH group on the 3′ carbon atom and is called the 3′ end. The sequence of nucleotides in the DNA segment shown in Figure 19.5 \"Structure of a Segment of DNA\" would be written 5′-dGdT-dA-dC-3′, which is often further abbreviated to dGTAC or just GTAC."
  },
  {
    "question": "What type of crust is made of basalt lavas that flow onto the seafloor?",
    "distractor3": "warm",
    "distractor1": "exotic",
    "distractor2": "endotopic",
    "correct_answer": "oceanic",
    "support": "There are two kinds of crust. Oceanic crust is made of basalt lavas that flow onto the seafloor. It is relatively thin, between 5 to 12 kilometers thick (3 - 8 miles). The rocks of the oceanic crust are denser (3.0 g/cm 3 ) than the rocks that make up the continents. Thick layers of mud cover much of the ocean floor."
  },
  {
    "question": "What formula  shows only the kinds and numbers of atoms in a molecule?",
    "distractor3": "nucleus formula",
    "distractor1": "plasma formula",
    "distractor2": "atomic formula",
    "correct_answer": "molecular formula",
    "support": "We use several kinds of formulas to describe organic compounds. A molecular formula shows only the kinds and numbers of atoms in a molecule. For example, the molecular formula C4H10 tells us there are 4 carbon atoms and 10 hydrogen atoms in a molecule, but it doesn’t distinguish between butane and isobutane. A structural formula shows all the carbon and hydrogen atoms and the bonds attaching them. Thus, structural formulas identify the specific isomers by showing the order of attachment of the various atoms. Unfortunately, structural formulas are difficult to type/write and take up a lot of space. Chemists often use condensed structural formulas to alleviate these problems. The condensed formulas show hydrogen atoms right next to the carbon atoms to which they are attached, as illustrated for butane:."
  },
  {
    "question": "The majority of elements, including iron and copper, are of what type?",
    "distractor3": "minerals",
    "distractor1": "oils",
    "distractor2": "acids",
    "correct_answer": "metals",
    "support": "There are almost 120 known elements. As you can see from Figure below , the majority of elements are metals. Examples of metals are iron (Fe) and copper (Cu). Metals are shiny and good conductors of electricity and heat. Nonmetal elements are far fewer in number. They include hydrogen (H) and oxygen (O). They lack the properties of metals."
  },
  {
    "question": "Hydrophilic molecules generally avoid what other kinds of molecules?",
    "distractor3": "neutral",
    "distractor1": "aqueous",
    "distractor2": "lipophilic",
    "correct_answer": "hydrophobic",
    "support": "Hydrophobic molecules “like” to be near other hydrophobic molecules. They “fear” being near hydrophilic molecules. The opposite is true of hydrophilic molecules. They “like” to be near other hydrophilic molecules. They “fear” being near hydrophobic molecules. These “likes” and “fears” explain why some molecules can pass through the cell membrane while others cannot."
  },
  {
    "question": "The name of a simple covalent compound can be determined from its chemical this?",
    "distractor3": "map",
    "distractor1": "models",
    "distractor2": "configuration",
    "correct_answer": "formula",
    "support": "The name of a simple covalent compound can be determined from its chemical formula."
  },
  {
    "question": "What are the smallest particles of matter?",
    "distractor3": "electrons",
    "distractor1": "ions",
    "distractor2": "molecules",
    "correct_answer": "atoms",
    "support": "All substances are made of atoms. Atoms are the smallest particles of matter. They cannot be divided into smaller particles. They also cannot be created or destroyed."
  },
  {
    "question": "Solid carbon dioxide is called what?",
    "distractor3": "blue ice",
    "distractor1": "carbohydrate",
    "distractor2": "liquid nitrogen",
    "correct_answer": "dry ice",
    "support": "Solid carbon dioxide is called dry ice because it does not pass through the liquid phase. Instead, it does directly to the gas phase. (Carbon dioxide can exist as liquid but only under high pressure. ) Dry ice has many practical uses, including the long-term preservation of medical samples."
  },
  {
    "question": "Most mercury compounds decompose when they are?",
    "distractor3": "cooled",
    "distractor1": "mixed",
    "distractor2": "filled",
    "correct_answer": "heated",
    "support": "Most mercury compounds decompose when heated. Most mercury compounds contain mercury with a 2+-oxidation state. When there is a large excess of mercury, it is possible to form compounds containing the Hg 2 2+ ion. All mercury compounds are toxic, and it is necessary to exercise great care in their synthesis."
  },
  {
    "question": "Where do extrusive igneous rocks cool at?",
    "distractor3": "in water",
    "distractor1": "underground",
    "distractor2": "in volcanoes",
    "correct_answer": "surface",
    "support": "Extrusive igneous rocks cool at the surface. Volcanoes are one type of feature that forms from extrusive rocks. Several other interesting landforms are also extrusive features. Intrusive igneous rocks cool below the surface. These rocks do not always remain hidden. Rocks that formed in the crust are exposed when the rock and sediment that covers them is eroded away."
  },
  {
    "question": "What is the term for something changing from water to ice?",
    "distractor3": "melting",
    "distractor1": "evaporation",
    "distractor2": "boiling",
    "correct_answer": "freezing",
    "support": ""
  },
  {
    "question": "What theory states that all matter consists of constantly moving particles?",
    "distractor3": "Big Bang theory",
    "distractor1": "inertia theory",
    "distractor2": "conservtion of matter",
    "correct_answer": "kinetic theory of matter",
    "support": "The particles that make up matter are also constantly moving. They have kinetic energy. The theory that all matter consists of constantly moving particles is called the kinetic theory of matter . You can learn more about it at the URL below."
  },
  {
    "question": "Electricity consists of a constant stream of what tiny particles?",
    "distractor3": "ions",
    "distractor1": "atoms",
    "distractor2": "quarks",
    "correct_answer": "electrons",
    "support": "You probably know that the wires strung between these high towers carry electricity. But do you know what electricity is? It actually consists of a constant stream of tiny particles called electrons. Electrons are negatively charged fundamental particles inside atoms. Atoms were discovered around 1800, but almost 100 years went by before electrons were discovered."
  },
  {
    "question": "What are atoms with unstable nuclei are considered to be?",
    "distractor3": "destructive",
    "distractor1": "ions",
    "distractor2": "unstable",
    "correct_answer": "radioactive",
    "support": "Atoms with unstable nuclei are radioactive. To become more stable, the nuclei undergo radioactive decay. In radioactive decay, the nuclei emit energy and usually particles of matter as well. There are several types of radioactive decay, including alpha, beta, and gamma decay. Energy is emitted in all three types of decay, but only alpha and beta decay also emit particles."
  },
  {
    "question": "In what form is atmospheric sulfur found?",
    "distractor3": "sulfur monoxide",
    "distractor1": "formaldehyde",
    "distractor2": "sulfuric acid",
    "correct_answer": "sulfur dioxide (so2)",
    "support": "On land, sulfur is deposited in four major ways: precipitation, direct fallout from the atmosphere, rock weathering, and geothermal vents (Figure 20.17). Atmospheric sulfur is found in the form of sulfur dioxide (SO2), and as rain falls through the atmosphere, sulfur is dissolved in the form of weak sulfuric acid (H2SO4). Sulfur can also fall directly from the atmosphere in a process called fallout. Also, as sulfur-containing rocks weather, sulfur is released into the soil. These rocks originate from ocean sediments that are moved to land by the geologic uplifting of ocean sediments. Terrestrial ecosystems can then make use of these soil sulfates (SO42-), which enter the food web by being taken up by plant roots. When these plants decompose and die, sulfur is released back into the atmosphere as hydrogen sulfide (H2S) gas."
  }
]