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Chapter 18 Exam

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 1. 
Under suitable conditions, roughly what proportion of all chemical reactions are reversible?
a.
none
c.
about half
b.
less than half
d.
nearly all
 

 2. 
A value of K near 1 indicates that at equilibrium probably
a.
only products are present.
b.
only reactants are present.
c.
significant quantities of both products and reactants are present.
d.
the reactions occur at a moderate rate.
 

 3. 
In the equation, mc003-1.jpgwhat represents the concentrations of the products?
a.
[Y] and [Z]
c.
mc003-2.jpg
b.
[W] and [X]
d.
mc003-3.jpg
 

 4. 
If the system 2CO(g) + O2(g) mc004-1.jpg 2CO2(g) has come to equilibrium and then more CO(g) is added,
a.
[CO2] increases and [O2] decreases.
c.
[CO2] decreases and [O2] decreases.
b.
[CO2] increases and [O2] increases.
d.
both [CO2] and [O2] remain the same.
 

 5. 
If more CO(g) is added to the system 2CO(g) + O2(g) mc005-1.jpg 2CO2(g) at constant temperature, K
a.
increases.
c.
increases or decreases.
b.
decreases.
d.
does not change.
 

 6. 
If a soluble product forms, a reaction may run to completion
a.
if the product is only slightly ionized.
b.
if the product is highly soluble.
c.
if the product is not gaseous.
d.
under no circumstances.
 

 7. 
Which reaction tends to run to completion?
a.
K+(aq) + mc007-1.jpg (aq) mc007-2.jpg KCl(s)
b.
2NO2(g) mc007-3.jpg N2O4(g)
c.
Ag+(aq) + mc007-4.jpg (aq) mc007-5.jpg AgCl(s)
d.
H2(g) + I2(g) mc007-6.jpg 2HI(g)
 

 8. 
Which reaction tends to run to completion?
a.
N2(g) + O2(g) mc008-1.jpg 2NO(g)
b.
H3O+(aq) + mc008-2.jpg(aq) mc008-3.jpg 2H2O(l)
c.
Na+(aq) +mc008-4.jpg(aq) mc008-5.jpg NaBr(s)
d.
H2(g) + CO(g) mc008-6.jpg C(s) + H2O(g)
 

 9. 
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+].
 

 10. 
In the equilibrium system CH3COOH(aq) + H2O(l) mc010-1.jpg H3O+(aq) + CH3COO–(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
 

 11. 
What is the chemical equilibrium expression for the ionization of acetic acid, shown in the reaction represented by the equation CH3COOH(aq) + H2O(l) mc011-1.jpg H3O+(aq) + CH3COOH–(aq)?
a.
[H3O+] [CH3COOH–]
c.
mc011-3.jpg
b.
mc011-2.jpg
d.
mc011-4.jpg
 

 12. 
How do Ka values for weak and strong acids compare?
a.
Ka (weak) = Ka (strong)
c.
Ka (weak) > Ka (strong)
b.
Ka (weak) < Ka (strong)
d.
not defined for weak acids
 

 13. 
To what degree does water ionize?
a.
completely
c.
slightly
b.
to a large extent
d.
not at all
 

 14. 
The pH of a solution is 10. The solution is
a.
acidic.
c.
neutral.
b.
basic.
d.
None of the above
 

 15. 
When small amounts of acids or bases are added to a solution of a weak acid and its salt, the pH
a.
always increases considerably.
b.
always decreases considerably.
c.
either increases or decreases considerably.
d.
remains nearly constant.
 

 16. 
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.
 

 17. 
If an acid is added to a solution of a weak base and its salt,
a.
more water forms and more weak base ionizes.
b.
the hydronium ion concentration decreases.
c.
more hydroxide ions form.
d.
more nonionized weak base forms.
 

 18. 
Which reaction describes an anion hydrolysis reaction?
a.
B+(aq) + H2O(l) mc018-1.jpg HB(aq) + OH+(aq)
b.
B–(aq) + H2O(l) mc018-2.jpg HB(aq) + OH–(aq)
c.
HB(aq) + H2O(l) mc018-3.jpg H3O+(aq) + B–(aq)
d.
B–(aq) + H2O(l) mc018-4.jpg BOH(aq) + H–(aq)
 

 19. 
What type of reaction occurs in an aqueous solution of the salt of a strong acid and a weak base?
a.
cation hydrolysis
c.
both cation and anion hydrolysis
b.
anion hydrolysis
d.
buffer hydrolysis
 

 20. 
A substance with a very low Ksp is
a.
insoluble or sparingly soluble.
c.
very soluble.
b.
moderately soluble.
d.
completely miscible in most solvents.
 

 21. 
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
 

 22. 
Calculate the ion product for mixing 100.0 mL of 0.0030 M CaCl2 with 100 mL of 0.0020 M Na2CO3. Ksp for CaCO3 is 1.4 mc022-1.jpg 10–8. Does a precipitate form?
a.
1.8 mc022-3.jpg 10–9; no
c.
1.5 mc022-5.jpg 10–6; no
b.
1.8 mc022-4.jpg 10–9; yes
d.
1.5 mc022-6.jpg 10–6; yes
 

 23. 
Calculate the ion product for mixing 50. mL of 0.000 70 M CuNO3 with 100. mL of 0.000 10 M NaCl. Ksp for CuCl is 1.2 ´ 10–6. Does a precipitate form?
a.
1.6 ´ 10–8; yes
c.
1.6 ´ 10–6; yes
b.
1.6 ´ 10–8; no
d.
1.6 ´ 10–6; no
 

 24. 
Calculate the ion product for mixing 300 mL of 0.000 30 M Sr(NO3)2 with 200 mL of 0.000 025 M K2SO4. Ksp for SrSO4 is 3.2 mc024-1.jpg 10–7. Does a precipitate form?
a.
5.6 mc024-3.jpg 10–6; yes
c.
1.8 mc024-5.jpg 10–9; yes
b.
5.6 mc024-4.jpg 10–6; no
d.
1.8 mc024-6.jpg 10–9; no
 

 25. 
Calculate the ion product for mixing 100 mL of 0.000 28 M Pb(NO3)2 with 200 mL of 0.0012 M NaCl. Ksp for PbCl2 is 1.9 mc025-1.jpg 10–4. Does a precipitate form?
a.
2.3 mc025-3.jpg 10–4; no
c.
6.0 mc025-5.jpg 10–11; no
b.
2.3 mc025-4.jpg 10–4; yes
d.
6.0 mc025-6.jpg 10–11; yes
 



 
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