Download Equilibrium Review True/False Indicate whether the statement is

Equilibrium Review
True/False
Indicate whether the statement is true or false.
____
1. (1 point) When changes are made to a system at equilibrium, the system shifts to a new equilibrium position.
____
2. (1 point) The presence of a common ion in a solution lowers the solubility of a dissolved substance.
____
3. (1 point) In an exothermic reaction, an increase in temperature favors the formation of products.
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
1. (1 point) In this reaction, which of the following factors will NOT change the concentration of CO2 in the
reaction?
a. a decrease in the volume of H2O
b. an increase in the amount of catalyst
____
c. a decrease in pressure
d. a decrease in temperature
2. (1 point) The equilibrium constant for the reaction
What is the concentration of carbon dioxide gas, if
at 700.0 K is 0.44.
and
?
a. 0.16 mol/L
b. 0.0014 mol/L
c. 0.075 mol/L
d. 0.75 mol/L
____
3. (1 point) In the reaction
heat is evolved. What happens when chlorine (Cl2) is added to
the equilibrium mixture at constant volume?
a. The temperature of the system increases.
b. The temperature of the system decreases.
c. More chlorine is produced.
d. The temperature remains unaffected.
____
4. (1 point) Which is true of the numerical value of the equilibrium constant,
?
a. It represents the relative concentration of products compared with reactants.
b. It represents the ratio of reactants to products.
c. It is measured in the SI unit, mole.
d. Both a and c are true.
e. Both b and c are true.
____
5. (1 point) Changing the volume in the reaction vessel of an equilibrium system has an effect on _________.
a. solids
b. liquids
c. gases
d. all of the above
e. none of the above
____
6. (1 point) Which of these affects the equilibrium constant,
a.
b.
c.
d.
e.
____
.
concentration
pressure
volume
temperature
all of the above
7. (1 point) A small amount of product is added to the equilibrium system below.
H2(g) + I2(g)  2HI(g)
Predict the result.
a.
b.
c.
d.
e.
The equilibrium shifts forward
The equilibrium shifts backward
There is no effect on the equilibrium
The change in equilibrium can not be predicted.
The reverse reaction no longer occurs.
Short Answer
1. (1 point) What three characteristics are common to all reactions that have reached equilibrium.
2. (1 point) Write the equilibrium constant expression for the following reaction:
A (s) + 3B (g) + 5C (g)  2D (s) + 1E (1)
3. (1 point) Explain why equilibrium will be unaffected if the pressure of the system below is tripled under
constant temperature.
H2(g) + I2(g)  2HI(g)
4. (1 point) Use the following information to answer the next question.
Consider the following equilibrium reaction:
3O2(g) + 64 kcal  2O3(g)
How would you increase the production of O3(g) by changing the temperature and pressure of the system?
Equilibrium Review
Answer Section
TRUE/FALSE
1. ANS: T
PTS: 1
DIF: Bloom's Level 1|DOK 1
NAT: UCP.4 | B.3 | B.6
2. ANS: T
PTS: 1
DIF: Bloom's Level 2|DOK 1
NAT: UCP.2 | UCP.4 | B.3
3. ANS: F
Heat is given out in the forward reaction of an exothermic reversible reaction. Therefore, exothermic reactions
are not favored at increased (high) temperature.
PTS: 1
DIF: Bloom's Level 2|DOK 1
NAT: UCP.4 | B.3
TOP: Describe how various factors affect chemical equilibrium.
KEY: Factors | Chemical equilibrium
MSC: 2
NOT: Exothermic reactions are favored at low temperature as they give out energy during the course of
reaction.
MULTIPLE CHOICE
1. ANS: B
A catalyst speeds up the reaction, but it does so in both directions equally.
PTS: 1
2. ANS: C
DIF: Bloom's Level 2|DOK 1
NAT: UCP.3 | B.2 | B.3 | B.6
Feedback
A
B
C
D
Here, the value of concentration of water is taken as 0.36 instead of 0.16.
Divide the product of the concentration of water, carbon monoxide, and the equilibrium
constant by the concentration of hydrogen, instead of multiplying it.
Correct! /d / The value of Keq is taken as 4.4 instead of 0.44.
PTS: 1
DIF: Bloom's Level 1|DOK 2
NAT: UCP.4 | B.3
TOP: Determine equilibrium concentrations of reactants and products.
KEY: Equilibrium constant
MSC: 3
3. ANS: B
Applying Le Chatelier’s principle, when chlorine is added to the equilibrium mixture, the equilibrium shifts to
the left. Thus, more heat is absorbed and the temperature decreases.
Feedback
A
B
C
D
4.
5.
6.
7.
Addition of chlorine increases the rate of backward reaction.
Correct!
More chlorine is consumed.
An increase in the rate of backward reaction affects the temperature.
PTS:
TOP:
KEY:
ANS:
MSC:
ANS:
MSC:
ANS:
MSC:
ANS:
MSC:
1
DIF: Bloom's Level 2|DOK 1
NAT: UCP.2 | UCP.4 | B.3
Explain how Le Chatelier's principle applies to equilibrium systems.
Le Chatelier's principle
MSC: 2
A
PTS: 1
LOC: E3.2
TOP: 7.1
K/U
C
PTS: 1
LOC: E3.3
TOP: 7.2
K/U
D
PTS: 1
LOC: E3.3
TOP: 7.2
K/U
B
PTS: 1
LOC: E2.2
TOP: 7.2
T/I
SHORT ANSWER
1. ANS:
1. The reaction must take place in a closed system.
2. The temperature must remain constant.
3. All reactants and products are present and are in constant dynamic motion.
PTS: 1
DIF: Bloom's Level 3|DOK 1
2. ANS:
Keq = [E]1 / [B]3[C]5
NAT: UCP.4 | B.3
Solids are omitted.
PTS: 1
DIF: Bloom's Level 3|DOK 1
NAT: UCP.3 | UCP.4
3. ANS:
Since the number of moles of the gaseous product is equal to the number of moles of the gaseous reactants,
the change in pressure will not affect the equilibrium, in accordance with the Le Chatelier’s principle.
PTS: 1
LOC: E3.3
TOP: 7.2
MSC: K/U
4. ANS:
Increasing pressure and temperature shift the reaction to product formation resulting in an increase in O3(g).
PTS: 1
LOC: E2.2
TOP: 7.2
MSC: T/I