Choose the best answer.
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1 | |
The proportion of oxygen in air is about ________________. |
| | A) | 1/5 |
| | B) | 1/3 |
| | C) | 1/2 |
| | D) | 4/5 |
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2 | |
A substance of unknown composition is heated in an open container. As a result, ______________. |
| | A) | its mass decreases |
| | B) | its mass remains the same |
| | C) | its mass increases |
| | D) | any of the above, depending on the nature of the substance and the temperature reached |
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3 | |
When a piece of metal is oxidized, the resulting oxide is _________________. |
| | A) | lighter than the original metal |
| | B) | the same weight as the original metal |
| | C) | heavier than the original metal |
| | D) | any of the above, depending on the metal |
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4 | |
Chemical energy is stored within atoms, molecules, and ions as _________________. |
| | A) | activation energy |
| | B) | electron kinetic energy |
| | C) | electron potential energy |
| | D) | thermal energy |
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5 | |
A chemical reaction that absorbs energy is called _________________. |
| | A) | endothermic |
| | B) | exothermic |
| | C) | activated |
| | D) | oxidation-reduction |
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6 | |
If a given reaction is exothermic, the reverse reaction ___________________. |
| | A) | is exothermic |
| | B) | is endothermic |
| | C) | may involve no energy change |
| | D) | any of the above, depending on the reaction |
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7 | |
Reactions that give off energy ________________. |
| | A) | never require activation energy |
| | B) | sometimes require activation energy |
| | C) | always require activation energy |
| | D) | always require catalysts |
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8 | |
The neutralization of a strong acid by a strong base ____________________. |
| | A) | absorbs energy |
| | B) | liberates energy |
| | C) | involves no energy change |
| | D) | requires a catalyst to occur |
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9 | |
The products of the complete combustion of hydrocarbon fuels are ________________. |
| | A) | H2 and CO |
| | B) | H2 and CO2 |
| | C) | H2O and CO |
| | D) | H2O and CO2 |
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10 | |
Of the following substances, the one that gives off the most heat per gram when it is burned is _________________. |
| | A) | hydrogen |
| | B) | methane |
| | C) | gasoline |
| | D) | coal |
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11 | |
Acid rain never contain dissolved _________________. |
| | A) | carbon dioxide |
| | B) | nitric acid |
| | C) | sulfuric acid |
| | D) | acetic acid |
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12 | |
The least polluting of the following fuels is _________________. |
| | A) | coal |
| | B) | gasoline |
| | C) | diesel fuel |
| | D) | natural gas |
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13 | |
Reaction rates increase with temperature primarily because ___________________. |
| | A) | dissociation into ions is more complete |
| | B) | more collisions occur between the molecules involved |
| | C) | more activated molecules are formed |
| | D) | equilibrium does not occur at high temperatures |
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14 | |
At equilibrium, _________________. |
| | A) | both forward and reverse reactions have ceased |
| | B) | the forward and reverse reactions are proceeding at the same rate |
| | C) | the forward reaction has come to a stop, and the reverse reaction is just about to begin |
| | D) | the mass of reactants equals the mass of products |
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15 | |
The yield of the product C in the reversible reaction A + B + energy ↔ C can be increased by ______________. |
| | A) | decreasing the temperature |
| | B) | increasing the temperature |
| | C) | increasing the surface area of the reactants |
| | D) | changing the catalyst |
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16 | |
Reduction occurs when a substance __________________. |
| | A) | loses electrons |
| | B) | gains electrons |
| | C) | combines with oxygen |
| | D) | reacts with an acid |
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17 | |
A catalyst affects which one or more of the following? |
| | A) | The energy needed for a chemical reaction to occur |
| | B) | The energy a chemical reaction gives off |
| | C) | The speed of a chemical reaction |
| | D) | Whether a substance is oxidized or reduced in a chemical reaction |
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18 | |
When an electric current is passed through molten sodium chloride, ____________________. |
| | A) | sodium metal is deposited at the positive electrode |
| | B) | sodium ions are deposited at the positive electrode |
| | C) | chlorine gas is liberated at the positive electrode |
| | D) | chlorine ions are liberated at the positive electrode |
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19 | |
The quantity actually stored in a "storage battery" is _________________. |
| | A) | electric charge |
| | B) | electric current |
| | C) | voltage |
| | D) | energy |
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20 | |
Batteries and fuel cells employ __________________. |
| | A) | oxidation reactions only |
| | B) | reduction reactions only |
| | C) | both oxidation and reduction reactions |
| | D) | acid-base neutralization reactions |
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