Matching (Value 5)
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Match each item with the correct statement below. a. | spontaneous reaction | d. | reaction mechanism | b. | entropy | e. | elementary reaction | c. | chemical
equilibrium |
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1.
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when the forward and reverse reactions take place at the same rate
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2.
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a reaction that releases free energy
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3.
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the measure of disorder
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4.
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Reactants are converted to products in a single step.
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5.
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includes all elementary reactions of a complex reaction
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Multiple Choice (Value 25) Identify the choice that best completes the statement or answers
the question.
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6.
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The energy that is available to do work in a reaction is called ____.
a. | heat | c. | entropy | b. | enthalpy | d. | free energy |
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7.
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Entropy measures ____.
a. | energy | c. | disorder | b. | heat transferred | d. | force |
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8.
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Which physical state of nitrogen has the highest entropy?
a. | solid | c. | gas | b. | liquid | d. | vapor |
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9.
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The amount of disorder in a system is measured by its ____.
a. | activation energy | c. | equilibrium position | b. | entropy | d. | K |
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10.
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Which one of the following systems has the highest entropy?
a. | 10 mL of water at 10C | b. | 10 mL of water at 50C | c. | 10 mL of water at
100C | d. | All have the same entropy because all are water. |
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11.
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If a system is left to change spontaneously, in what state will it end?
a. | the same state in which it began | b. | the state with lowest possible
energy | c. | the state with the maximum disorder | d. | the state with the lowest possible energy
consistent with the state of maximum disorder |
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12.
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Which reaction results in the greatest increase in entropy?
a. | A ® B | c. | 2A ® B | b. | A ®
2B | d. | 3A ® B |
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13.
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In which of these systems is the entropy decreasing?
a. | air escaping from a tire | c. | salt dissolving in
water | b. | snow melting | d. | a liquid cooling |
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14.
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Which of the following statements explains why the melting of ice is a
spontaneous reaction at room temperature and pressure?
a. | Melting is accompanied by a decrease of entropy. | b. | Melting is
accompanied by an increase of entropy. | c. | Melting is accompanied by a decrease of
energy. | d. | Melting is accompanied by an increase of energy. |
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15.
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The two factors that determine whether a reaction is spontaneous or
nonspontaneous are ____.
a. | entropy and disorder | b. | entropy and energy | c. | electron
configuration and ionic charge | d. | energy and heat of
reaction |
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16.
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Which of the following statements is true?
a. | All spontaneous processes are exothermic. | b. | All nonspontaneous
processes are endothermic. | c. | All spontaneous processes release free
energy. | d. | Entropy always increases in a spontaneous process. |
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17.
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Spontaneous reactions ____.
a. | are always exothermic | b. | always take place at a rapid
rate | c. | always result in increased disorder of the system | d. | always release free
energy |
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18.
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The melting of ice at temperatures above 0 C ____.
a. | liberates heat | c. | is not favorable | b. | is not spontaneous | d. | is endothermic |
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19.
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Which of the following is true about the combustion of carbon?
a. | The reaction is spontaneous. | b. | Carbon is produced from oxygen and carbon
dioxide. | c. | Enthalpy remains constant. | d. | Entropy
decreases. |
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20.
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What determines whether or not a reaction is spontaneous?
a. | change in molar volume and heat change | b. | change in enthalpy only | c. | enthalpy change and
entropy change | d. | change in entropy only |
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21.
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Which of the following is true about the numerical value of Gibbs free-energy
change for a spontaneous reaction?
a. | It is not related to enthalpy. | b. | It is negative. | c. | It indicates that
work must be expended. | d. | It is positive for temperatures above 850C. |
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22.
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Which variable is NOT required to calculate the Gibbs free-energy change for a
chemical reaction?
a. | change in enthalpy | c. | temperature in kelvins | b. | temperature in C | d. | change in
entropy |
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23.
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What is the rate law for the following reaction? A + 2B ® C + D
a. | rate = k[A][B] | c. | rate =
k[A][B] | b. | rate = k[A][B] | d. | rate = k[A][B] |
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24.
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What is the order of the following reaction? A + 2B ® C + D
a. | zero | c. | second | b. | first | d. | third |
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25.
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In a first-order reaction, how does the rate change if the concentration of the
reactant decreases to one-third its original value?
a. | The rate decreases by a factor of one-ninth. | b. | The rate decreases
by a factor of one-third. | c. | The rate decreases by a factor of
one-half. | d. | The rate stays the same. |
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26.
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If a reaction rate decreases by a factor of one-ninth when a reactant
concentration is decreased by one-third, what is the order of the reaction with respect to that
reactant?
a. | fourth | c. | second | b. | third | d. | first |
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27.
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When nitrous oxide is converted to nitrogen and oxygen, what is the term used to
describe the oxygen atoms formed?
a. | reactants | c. | activated complexes | b. | products | d. | intermediates |
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28.
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An elementary reaction ____.
a. | has only elements as reactants | b. | has only elements as
products | c. | never needs a catalyst | d. | converts reactants to products in a single
step |
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29.
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For a complex reaction, the reaction progress curve ____.
a. | is a flat line | c. | has several hills and valleys | b. | has only one
peak | d. | shows energy versus
pressure |
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30.
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What information is NOT given by an overall equation for a chemical
reaction?
a. | the relative numbers of molecules used | b. | the probable order of the
reaction | c. | the number of atoms participating in the reaction | d. | the reaction
mechanism |
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Short Answer
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31.
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Calculate the concentration of a silver ion when the solubility product constant
of AgI is 10 .
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32.
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What is the approximate concentration of aluminum ions if the solubility product
constant of Al(OH) is 27 10 ?
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33.
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The solubility product constant of calcium hydroxide is 6.5 10 . If 0.10 mol of sodium hydroxide is added to 1 L of 0.0010 M Ca(OH) , what is
the final concentration of the calcium ion?
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34.
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In a first-order reaction, what is the rate constant if the rate is
0.050M/s and the reactant concentration is 0.030M?
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35.
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What is the rate of a first-order reaction that has a reactant concentration of
1.1M and a rate constant of 0.14/s?
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36.
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In a first-order reaction, what is the reactant concentration if the rate
constant is 0.2/s and the rate is 0.004M/s?
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37.
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What is the rate of a first-order reaction that has a reactant concentration of
0.1M and a rate constant of 0.1/s?
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38.
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In a first-order reaction, what is the reactant concentration if the rate
constant is 0.1/s and the rate is 0.001M/s?
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39.
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In a first-order reaction, what is the rate constant if the rate is
0.01M/s and the reactant concentration is 0.01M?
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40.
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The rate law for the following reaction is: Rate = k[A] [B] . aA + bB cC + dD From the following
data, find the kinetic order of the reaction with respect to A and B, as well as the overall
order. Initial Concentration Initial
Concentration Initial Rate of A(mol/L)
of B(mol/L)
(mol/L s) 0.05
0.05
2 10 0.10
0.05
4 10 0.20
0.05
8 10 0.01
0.05
0.4 10 0.01
0.10
3.2 10 0.01
0.20
25.6 10
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41.
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In a two-step reaction mechanism, how many elementary reactions occur?
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