Multiple Choice
Identify the
choice that best completes the statement or answers the question.
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1.
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If HgO is heated in a closed container,
a. | no reaction takes place. | b. | the HgO decomposes. | c. | Hg2O2 forms. | d. | the HgO decomposes and then
recombines. |
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2.
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At equilibrium,
a. | all reactions have ceased. | b. | only the forward reaction
continues. | c. | only the reverse reaction continues. | d. | both the forward and reverse reactions
continue. |
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3.
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What two processes are at equilibrium in a saturated sugar solution?
a. | evaporation and condensation | c. | decomposition and
synthesis | b. | dissolving and crystallization | d. | ionization and
recombination |
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4.
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The value of the equilibrium constant for a reaction
a. | changes with concentration. | c. | changes with
temperature. | b. | changes with time. | d. | is the same under all conditions. |
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5.
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How does the value of K show that a reaction reaches equilibrium very
quickly?
a. | K is large. | b. | K is small. | c. | K is
zero. | d. | The value of K does not show how quickly a reaction comes to
equilibrium. |
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6.
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A very high value of K indicates that
a. | equilibrium is reached slowly. | c. | reactants are
favored. | b. | products are favored. | d. | equilibrium has been reached. |
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7.
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The value of K for a system
a. | can be calculated from the molar masses of products and
reactants. | b. | can be calculated from the enthalpies of the forward and reverse
reactions. | c. | can be calculated from the chemical properties of products and
reactants. | d. | must be measured by experiment. |
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8.
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When the chemical equilibrium expression is written, coefficients from the
equation for the reaction
a. | appear as coefficients. | c. | appear as
subscripts. | b. | appear as exponents. | d. | do not appear. |
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9.
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An equilibrium mixture of SO 2, O 2, and SO 3
gases at 1500 K is determined to consist of 0.344 mol/L SO 2, 0.172 mol/L O 2,
and 0.56 mol/L SO 3. What is the equilibrium constant for the system at this temperature?
The balanced equation for this reaction is 2SO 2( g) + O 2( g)  2SO 3( g).
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10.
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If a reaction system has come to equilibrium, it can be made to run to
completion
a. | only if it is not reversible. | c. | by removing a
product. | b. | only if the temperature is low enough. | d. | under no
circumstances. |
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11.
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Reactions tend to run to completion if
a. | a gaseous product forms and escapes. | b. | a product in the same phase as the reactants
forms. | c. | one product is highly ionized. | d. | one product is highly
soluble. |
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12.
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The common-ion effect promotes
a. | dissolving. | c. | boiling. | b. | precipitation. | d. | ionization. |
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13.
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The common-ion effect
a. | promotes condensation. | c. | reduces ionization. | b. | promotes evaporation. | d. | increases
solubility. |
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14.
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In which solution does adding hydrogen chloride promote precipitation?
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15.
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Adding sodium acetate to an acetic acid, CH3COOH, solution
a. | increases pH and lowers [H+]. | b. | increases pH and
raises [H+]. | c. | decreases pH and lowers
[H+]. | d. | decreases pH and raises
[H+]. |
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16.
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In the equilibrium system CH 3COOH( aq) +
H 2O( l)  H 3O +( aq) +
CH 3COO –( aq), which reaction proceeds more rapidly at
equilibrium? a. | the forward reaction | c. | both reactions stop | b. | the reverse reaction | d. | both reactions proceed at the same
rate |
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17.
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What is the equation for the ionization of water?
a. | 2H2O(l) 
H3O+(aq) + OH–(aq) | c. | 2H2O(l)  2H2(g) +
O2(g) | b. | 2H2O(l) 
H3O–(aq) + OH+(aq) | d. | H2O(l) 
H–(aq) + OH+(aq) |
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18.
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If a base is added to a solution of a weak acid and its salt,
a. | more of the nonionized weak acid forms. | b. | more of the
nonionized acid ionizes. | c. | precipitation occurs. | d. | the hydronium ion
concentration decreases. |
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19.
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If a base is added to a solution of a weak base and its salt,
a. | the hydronium ion concentration increases. | b. | more of the weak
base ionizes. | c. | more hydroxide ions form. | d. | more water and nonionized base
forms. |
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20.
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What is the solubility-product constant of magnesium hydroxide,
Mg(OH)2? Its solubility is 9.0 ´ 10–4 g/100 g H2O. The
molar mass of Mg(OH)2 is 58.32 g/mol.
a. | 1.8 ´ 10–6 | c. | 1.5 ´ 10–11 | b. | 4.5 ´
10–9 | d. | 6.2
´ 10–12 |
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21.
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What is the solubility in mol/L of cobalt(II) sulfide, CoS? Its
Ksp value is 3.0 ´ 10–26.
a. | 5.9  10–10 | c. | 1.7 
10–13 | b. | 1.7  10–12 | d. | 1.7 
10–26 |
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22.
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What is the solubility in mol/L of copper(I) chloride, CuCl? Its
Ksp value is 1.2 ´ 10–6.
a. | 1.1 ´ 10–3 | c. | 2.3 ´ 10–5 | b. | 1.8 ´
10–4 | d. | 2.7
´ 10–5 |
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23.
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What is the solubility in mol/L of copper(I) sulfide, Cu2S? Its
Ksp value is 2.5 ´ 10–48.
a. | 4.1 ´ 10–14 | c. | 8.5 ´ 10–17 | b. | 6.2 ´
10–16 | d. | 1.8
´ 10–24 |
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24.
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Calculate the ion product for mixing 100 mL of 0.000 28 M
Pb(NO 3) 2 with 200 mL of 0.0012 M NaCl. Ksp for
PbCl 2 is 1.9  10 –4.
Does a precipitate form? a. | 2.3  10–4; no | c. | 6.0  10–11;
no | b. | 2.3  10–4;
yes | d. | 6.0  10–11;
yes |
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25.
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Calculate the ion product for mixing 50 mL of 0.015 M
Ca(NO3)2 with 200 mL of 0.35 M NaOH. Ksp for
Ca(OH)2 is 5.5 ´ 10–6. Does a precipitate
form?
a. | 8.5 ´ 10–7; no | c. | 2.4 ´ 10–4; no | b. | 8.5 ´
10–7; yes | d. | 2.4 ´ 10–4;
yes |
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