January 2015 Chemistry Regents #21-25
Highlight to reveal answers and explanations
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Questions | Answer | Links | Explanations |
| 21 Which mathematical expression represents the heat of reaction for a chemical reaction? (1) (the heat of fusion) – (the heat of vaporization) (2) (the heat of vaporization) – (the heat of fusion) (3) (the potential energy of the products) – (the potential energy of the reactants) (4) (the potential energy of the reactants) – (the potential energy of the products) | 3 | links | prod-react |
| 22 At 101.3 kPa and 298 K, a 1.0-mole sample of which compound absorbs the greatest amount of heat as the entire sample dissolves in water? (1) LiBr (3) NaOH (2) NaCl (4) NH4Cl | 4 | links | Bottom of Table I |
| 23 For a reaction at equilibrium, which change can increase the rates of the forward and reverse reactions? (1) a decrease in the concentration of the reactants (2) a decrease in the surface area of the products (3) an increase in the temperature of the system (4) an increase in the activation energy of the forward reaction | 3 | links | See link |
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| 24 Which reaction produces ethanol? (1) combustion (3) fermentation (2) esterification (4) polymerization | 3 | links | definition |
| 25 The chemical process in which electrons are gained by an atom or an ion is called (1) addition (3) reduction (2) oxidation (4) substitution | 3 | links | GER-gain electrons reduction |
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