Name:______________________________________________ Date:________________ Period:____
Ch. 13, 15 – Equilibrium, Ksp Review
1. Which of the following statements concerning equilibrium is not true?
a)
b)
c)
d)
e)
A system that is disturbed from an equilibrium condition responds in a manner to
restore equilibrium.
Equilibrium in molecular systems is dynamic, with two opposing processes balancing
one another.
The value of the equilibrium constant for a given reaction mixture is the same regardless
of the direction from which equilibrium is attained.
A system moves spontaneously toward a state of equilibrium.
The equilibrium constant is independent of temperature.
PAGE: 13.1,2
2. Which of the following statements is true?
a)
b)
c)
d)
e)
PAGE: 13.1,7
When two opposing processes are proceeding at identical rates, the system is at
equilibrium.
Catalysts are an effective means of changing the position of an equilibrium.
The concentration of the products equals that of reactants and is constant at equilibrium.
An endothermic reaction shifts toward reactants when heat is added to the reaction.
None of these statements is true.
3. Consider the gaseous reaction CO(g) + Cl2(g)
terms of K?
a)
b)
c)
d)
e)
COCl2(g). What is the expression for Kp in
K(RT)
K/(RT)
K(RT)2
K/(RT)2
1/K(RT)
PAGE: 13.3
4.
Consider the following reaction: CS2(g) 4H2(g)
CH4(g) + 2H2S(g)
The equilibrium constant K is 0.28 at 900C. What is Kp at this temperature?
a)
b)
c)
d)
e)
PAGE: 13.3
5.0  10–5
4.0  10–5
3.0  10–5
2.0  10–5
1.0  10–5
5. Consider the following system at equilibrium:
N2(g) + 3H2(g)
2NH3(g) + 92.94 kJ
Which of the following changes will shift the equilibrium to the right?
I. increasing the temperature
II. decreasing the temperature
III. increasing the volume
IV. decreasing the volume
V. removing some NH3
VI. adding some NH3
VII. removing some N2
VIII. adding some N2
a) I, IV, VI, VII
b) II, III, V, VIII
c) I, VI, VIII
d) I, III, V, VII
e) II, IV, V, VIII
PAGE: 13.7
6.
Given the equation: 2NOCl2(g)
115C. Calculate Kp.
a)
b)
c)
d)
e)
2NO(g) + Cl2(g). The equilibrium constant is 0.0150 at
0.0150
0.478
0.142
1.41 x 10-4
none of these
PAGE: 13.3
7.
Consider the reaction:
CaCl2(s) + 2H2O(g)
CaCl2  2H2O(s)
The equilibrium constant for the reaction as written is
[CaCl2  2H 2 O]
a)
K=
b)
K=
c)
1
K = 2[H O]
d)
K = [H2O]2
e)
K=
PAGE: 13.4
[CaCl2 ][H 2 O]2
1
[H2O]2
2
[CaCl2  2H 2 O]
[H 2 O]2
8–9.
Consider the following equilibrium:
H2(g) + I2(s)
2HI(g)
H = +68.0 kJ/mol
8. The proper Keq expression is:
a)
[H2][I2]
[HI]
b)
([H2][I2])
[HI]2
c)
[HI]
([H2])
d)
[HI]2
[H2][I2]
e)
[HI]2
[H2]
PAGE: 13.4
9. Which of the following statements about the equilibrium is false?
a)
b)
c)
d)
e)
PAGE: 13.7
If the system is heated, the right side is favored.
This is a heterogeneous equilibrium.
If the pressure on the system is increased by changing the volume, the left side is
favored.
Adding more H2(g) increases the equilibrium constant.
Removing HI as it forms forces the equilibrium to the right.
10–13. Consider the following equilibrium:
2NOCl(g)
2NO(g) + Cl2(g)
with K = 1.6  10–5. 1.00 mole of pure NOCl and 1.00 mole of pure Cl2 are replaced in a 1.00-L
container.
10. If x moles of NOCl react, what is the equilibrium concentration of NO?
a)
b)
c)
d)
e)
PAGE: 13.6
+x
+2x
–x
–2x
x2
11. If x moles of NOCl react, what is the equilibrium concentration of Cl2?
a)
+x
b)
x
+2
c)
1+x
d)
x
1+2
e)
1 + 2x
PAGE: 13.6
12. Calculate the equilibrium concentration of NO(g).
a)
b)
c)
d)
e)
PAGE: 13.6
1.0 M
1.6  10–5 M
0.50 M
6.2  10–4 M
4.0  10–3 M
13. Calculate the equilibrium concentration of Cl2(g).
a)
b)
c)
d)
e)
PAGE: 13.6
1.6  10–5 M
1.0 M
0.50 M
6.2  10–4 M
4.0  10–3 M
14–17. The questions below refer to the following system:
Cobalt chloride is added to pure water. The Co2+ ions hydrate. The hydrated form then reacts
with the Cl– ions to set up the equilibrium shown here:
Co(H2O)62+ + 4 Cl–
(pink)
CoCl42– + 6H2O
(blue)
14. Which statement below describes the change that the system will undergo if hydrochloric acid
is added?
a)
b)
c)
d)
e)
PAGE: 13.7
It should become more blue.
It should become more pink.
The equilibrium will shift to the right.
The equilibrium will shift to the left.
Two of these.
15. Which statement below describes the change that the system will undergo if water is added?
a)
b)
c)
d)
e)
PAGE: 13.7
More chlorine ions will be produced.
More water will be produced.
The equilibrium will shift to the right.
The color will become more blue.
There will be less of the hydrated cobalt ion at the new equilibrium position.
16. Which statement below describes the change that the system will undergo if silver nitrate is
added?
a)
b)
c)
d)
e)
PAGE: 13.7
It should become more blue.
It should become more pink.
Water will be produced.
The silver ion will react with the CoCl42–.
Nothing will change.
17. Which statement below describes the change that the system will undergo if acetone (whose
density is lower than water and is insoluble in water) is added?
a)
b)
c)
d)
e)
PAGE: 13.7
The system will become pink on the top and blue on the bottom.
The system will become blue on the top and pink on the bottom.
The system will become intensely pink in the middle.
The system will become intensely blue on the top and clear on the bottom.
The system will become intensely pink on the top and clear on the bottom.
18–20. The following questions refer to the equilibrium shown here:
4NH3(g) + 502(g)
4NO(g) + 6H2O(g)
18. What would happen to the system if oxygen were added?
a)
b)
c)
d)
e)
PAGE: 13.7
More ammonia would be produced.
More oxygen would be produced.
The equilibrium would shift to the right.
The equilibrium would shift to the left.
Nothing would happen.
19. What would happen to the system if the pressure were decreased?
a)
b)
c)
d)
e)
PAGE: 13.7
Nothing would happen.
More oxygen would be produced.
The water vapor would become liquid water.
The ammonia concentration would increase.
The NO concentration would increase.
20. For a certain reaction at 25.0C, the value of K is 1.2 x 10-3. At 50.0C the value of K is 3.4 x 10-1.
This means that the reaction is
a)
b)
c)
d)
e)
PAGE: 13.7
exothermic.
endothermic.
never favorable.
More information is needed.
None of these (a-d)
21.
Find the solubility (in mol/L) of lead chloride (PbCl2) at 25C. Ksp = 1.6  10–5
a)
b)
c)
d)
e)
1.6  10–2
0.020
7.1  10–5
2.1
9.3  10–3
PAGE: 15.6
22.
Solubility Products (Ksp)
BaSO4
1.5 10–9
CoS
5.0 10–22
PbSO4
1.3 10–8
AgBr
5.0 10–13
Which of the following compounds is the most soluble (in moles/liter)?
a)
b)
c)
d)
e)
BaSO4
CoS
PbSO4
AgBr
BaCO3
PAGE: 15.6
23.
You have a solution consisting of 0.10 M Cl– and 0.10 M CrO42–. You add 0.10 M silver nitrate
dropwise to this solution. Given that the Ksp for Ag2CrO4 is 9.0  10–12, and that for AgCl is 1.6
 10–10, which of the following will precipitate first?
a)
b)
c)
d)
e)
silver chloride
silver chromate
silver nitrate
cannot be determined by the information given
none of these
PAGE: 15.7
24. Which of the following compounds has the lowest solubility in mol/L in water?
a)
b)
c)
d)
e)
PAGE: 15.6
Al(OH)3
CdS
PbSO4
Sn(OH)2
MgC2O4
Ksp = 2  10–32
Ksp = 1.0  10–28
Ksp = 1.3  10–8
Ksp = 3  10–27
Ksp = 8.6  10–5
25.
The molar solubility of PbI2 is 1.5 x 10-3 M. Calculate the value of Ksp for PbI2.
a)
b)
c)
d)
e)
1.5 x 10-3
2.3 x 10-6
1.4 x 10-8
3.4 x 10-9
none of these
PAGE: 15.6
26.
Calculate the concentration of the silver ion in a saturated solution of silver chloride, AgCl
(Ksp = 1.6 x 10-10).
a)
b)
c)
d)
e)
5.4 x 10-4
1.3 x 10-5
1.6 x 10-10
8.0 x 10-11
none of these
PAGE: 15.6
27.
It is observed that 7.5 mmol of BaF2 will dissolve in 1.0 L of water. Use these data to calculate
the values of Ksp for barium fluoride.
a)
b)
c)
d)
e)
7.5  10–3
4.2  10–7
1.7  10–6
5.6  10–5
2.1  10–12
PAGE: 15.6
28.
The Ksp of PbSO4(s) is 1.3  10–8. Calculate the solubility (in mol/L) of PbSO4(s) in a 0.0010 M
solution of Na2SO4.
a)
b)
c)
d)
e)
PAGE: 15.6
1.3  10–11 M
4.5  10–6 M
1.3  10–5 M
1.3  10–8 M
1.4  10–4 M
29–30.
The next two questions refer to the following: The solubility of silver phosphate (Ag3PO4) at
25C is 1.6  10–5 mol/L.
29. Determine the concentration of the Ag+ ion in a saturated solution.
a)
b)
c)
d)
e)
PAGE: 15.6
1.6  10–5 M
3.2  10–5 M
4.8  10–5 M
6.4  10–5 M
7.6  10–5 M
30. What is the Ksp for the silver phosphate at 25C?
a)
b)
c)
d)
e)
PAGE: 15.6
7.7  10–10
1.8  10–18
8.6  10–13
3.3  10–13
none of these
Free Response Question
C(s) + H2O(g)  CO(g) + H2(g)
Hº = +131kJ
A rigid container holds a mixture of graphite pellets (C(s)), H2O(g), CO(g), and H2(g) at equilibrium.
State whether the number of moles of CO(g) in the container will increase, decrease, or remain the
same after each of the following disturbances is applied to the original mixture. For each case, assume
that all other variables remain constant except for the given disturbance. Explain each answer with a
short statement.
1.
(a) Additional H2(g) is added to the equilibrium mixture at constant volume.
(b) The temperature of the equilibrium mixture is increased at constant volume.
(c) The volume of the container is decreased at constant temperature.
(d) The graphite pellets are pulverized.