Which of the following statements concerning equilibrium is not true?
A.
A system that is disturbed from an equilibrium condition responds in a manner to restore equilibrium.
B.
Equilibrium in molecular systems is dynamic, with two opposing processes balancing one another.
C.
The value of the equilibrium constant for a given reaction mixture is the same regardless of the direction from which equilibrium is attained.
D.
A system moves spontaneously toward a state of equilibrium.
E.
The equilibrium constant is independent of temperature.
2.
Which of the following statements is true?
A.
When two opposing processes are proceeding at identical rates, the system is at equilibrium.
B.
Catalysts are an effective means of changing the position of an equilibrium.
C.
The concentration of the products equals that of reactants and is constant at equilibrium.
D.
An endothermic reaction shifts toward reactants when heat is added to the reaction.
E.
None of these statements is true.
3.
Indicate the mass action expression for the following reaction:
A.
[X]2[Y][W]3[V]
B.
C.
D.
4.
The value of the equilibrium constant, K, is dependent on I. The temperature of the system. II. The nature of the reactants and products. III. The concentration of the reactants. IV. The concentration of the products.
A.
I, II
B.
II, III
C.
III, IV
D.
It is dependent on three of the above choices.
E.
It is not dependent on any of the above choices.
5.
Consider the chemical system K = 4.6 ´ 109 L/mol.
How do the equilibrium concentrations of the reactants compare to the equilibrium concentration of the product?
A.
They are much smaller.
B.
They are much bigger.
C.
They are about the same.
D.
They have to be exactly equal.
E.
You can't tell from the information given.
6.
At 500.0 K, one mole of gaseous ONCl is placed in a one-liter container. At equilibrium it is 9.0% dissociated according to the equation shown here:
Determine the equilibrium constant.
A.
4.4 ´ 10–4
B.
2.2 ´ 102
C.
1.1 ´ 102
D.
2.2 ´ 10–4
E.
9.1 ´ 10–1
7.
Consider the reaction
whose K = 54.8 at 425°C. If an equimolar mixture of reactants gives the concentration of the product to be 0.50 M at equilibrium, determine the concentration of the hydrogen.
A.
4.6 ´ 10–3 M
B.
6.8 ´ 10–2 M
C.
1.2 ´ 10–3 M
D.
9.6 ´ 10–2 M
E.
1.6 ´ 10–4 M
8.
Consider the gaseous reaction
What is the expression for Kp in terms of K?
A.
K(RT)
B.
K/(RT)
C.
K(RT)2
D.
K/(RT)2
E.
1/K(RT)
9.
Find the value of the equilibrium constant (K) (at 500 K) for The value for Kp at 500 K is 1.5 ´ 10–5/atm2.
A.
7.5 ´ 10–2
B.
1.3 ´ 10–2
C.
9.6 ´ 10–2
D.
2.5 ´ 10–2
E.
6.0 ´ 10–2
10.
Consider the following system at equilibrium: 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
11.
If the equilibrium constant for
is 0.123, then the equilibrium constant for
A.
1.00 – 2(0.123)
B.
8.13
C.
0.123
D.
66.1
E.
16.3
12.
Calculate Kp for
at 600 K, using the following data:
A.
4.4 ´ 1043
B.
9.8 ´ 1024
C.
1.2 ´ 10–4
D.
5.4 ´ 10–13
E.
2.6 ´ 10–31
13.
For the reaction below, Kp = 1.16 at 800°C. If a 20.0-gram sample of CaCO3 is put into a 10.0-liter container and heated to 800°C, what percent of the CaCO3 will react to reach equilibrium?
A.
14.6%
B.
65.9%
C.
34.1%
D.
100.0%
E.
none of these
14.
The reaction has Kp = 45.9 at 763 K. A particular equilibrium mixture at that temperature contains gaseous HI at a partial pressure of 4.00 atm and hydrogen gas at a partial pressure of 0.200 atm. What is the partial pressure of I2?
A.
0.200 atm
B.
0.436 atm
C.
1.74 atm
D.
0.574 atm
E.
14.3 atm
15.
For the reaction given below, 3.00 moles of A and 4.00 moles of B are placed in a 5.00-L container.
At equilibrium, the concentration of A is 0.40 mol/L. What is the value of K?
A.
0.89
B.
1.80
C.
2.00
D.
3.00
E.
none of these
16.
The following reaction is investigated (assume an ideal gas mixture): Initially there are 0.10 moles of N2O and 0.25 moles of N2H4, in a 10.0-L container. If there are 0.06 moles of N2O at equilibrium, how many moles of N2 are present at equilibrium?
A.
0.9
B.
0.04
C.
0.06
D.
0.02
E.
none of these
17.
Consider the reaction
At 1273 K the Kp value is 167.5. What is the PCO at equilibrium if the PCO2 is 0.10 atm at this temperature?
A.
16.7 atm
B.
2.0 atm
C.
1.4 atm
D.
4.1 atm
E.
250 atm
18.
The reaction quotient for a system is 7.2 ´ 102. If the equilibrium constant for the system is 36, what will happen as equilibrium is approached?
A.
There will be a net gain in product.
B.
There will be a net gain in reactant.
C.
There will be a net gain in both product and reactant.
D.
There will be no net gain in either product or reactant.
E.
The equilibrium constant will decrease until it equals the reaction quotient.
19.
Nitric oxide, an important pollutant in air, is formed from the elements nitrogen and oxygen at high temperatures, such as those obtained when gasoline burns in an automobile engine. At 2000°C, K for the reaction is 0.01.
Predict the direction in which the system will move to reach equilibrium at 2000°C if 0.4 moles of N2, 0.1 moles of O2, and 0.08 moles of NO are placed in a 1.0-liter container.
A.
The system remains unchanged.
B.
The concentration of NO will decrease; the concentrations of N2 and O2 will increase.
C.
The concentration of NO will increase; the concentrations of N2 and O2 will decrease.
D.
The concentration of NO will decrease; the concentrations of N2 and O2 will remain unchanged.
E.
More information is necessary.
20.
Consider the following reaction: Given 1.00 mole of HF(g), 0.500 mole of H2(g), and 0.750 mole of F2(g) are mixed in a 5.00-L flask, determine the reaction quotient, Q, and the net direction to achieve equilibrium.
A.
Q = 0.150; the equilibrium shifts to the right.
B.
Q = 0.375; the equilibrium shifts to the left.
C.
Q = 0.150; the equilibrium shifts to the left.
D.
Q = 0.375; the equilibrium shifts to the right.
E.
Q = 0.150; the system is at equilibrium.
21.
The questions below refer to the following system: A 2-liter flask initially contains 1.2 mol of gas A and 0.60 mol of gas C. Gas A decomposes according to the following reaction: The equilibrium concentration of gas B is 0.20 mol/L.
Determine the equilibrium concentration of gas A.
A.
0.8 M
B.
0.2 M
C.
0.6 M
D.
0.4 M
E.
0.3 M
22.
The questions below refer to the following system: A 2-liter flask initially contains 1.2 mol of gas A and 0.60 mol of gas C. Gas A decomposes according to the following reaction: The equilibrium concentration of gas B is 0.20 mol/L.
Determine the equilibrium concentration of gas C.
A.
0.3 M
B.
0.5 M
C.
0.9 M
D.
1.2 M
E.
1.5 M
23.
Nitrogen gas (N2) reacts with hydrogen gas (H2) to form ammonia (NH3). At 200°C in a closed container, 1.0 atm of nitrogen gas is mixed with 2.0 atm of hydrogen gas. At equilibrium, the total pressure is 2.0 atm. Calculate the partial pressure of hydrogen gas at equilbrium.
A.
2.0 atm
B.
0.50 atm
C.
1.5 atm
D.
0.0 atm
E.
none of these
24.
Given the reaction
You have the gases A, B, C, and D at equilibrium. Upon adding gas A, the value of K:
A.
increases because by adding A, more products are made, increasing the product to reactant ratio.
B.
decreases because A is a reactant o the product to reactant ratio decreases.
C.
does not change because A does not figure into the product to reactant ratio.
D.
does not change as long as the temperature is constant.
E.
depends on whether the reaction is endothermic or exothermic.
25.
The equilibrium system
has a very small equilibrium constant: K = 2.6 ´ 10–6. Initially 3 moles of A are placed in a 1.5-L flask. Determine the concentration of C at equilibrium.
A.
0.011 M
B.
0.022 M
C.
0.033 M
D.
0.044 M
E.
2.0 M
26.
Ammonia is prepared industrially by the reaction: For the reaction, DH° = –92.2 kJ and K (at 25°C) = 4.0 ´ 108. When the temperature of the reaction is increased to 500°C, which of the following is true?
A.
K for the reaction will be larger at 500°C than at 25°C.
B.
At equilibrium, more NH3 is present at 500°C than at 25°C.
C.
Product formation (at equilibrium) is not favored as the temperature is raised.
D.
The reaction of N2 with H2 to form ammonia is endothermic.
E.
None of these is true.
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whose K = 54.8 at 425°C. If an equimolar mixture of reactants gives the concentration of the product to be 0.50 M at equilibrium, determine the concentration of the hydrogen.
What is the expression for Kp in terms of K?
is 0.123, then the equilibrium constant for
at 600 K, using the following data:
At 1273 K the Kp value is 167.5. What is the PCO at equilibrium if the PCO2 is 0.10 atm at this temperature?
You have the gases A, B, C, and D at equilibrium. Upon adding gas A, the value of K:
has a very small equilibrium constant:
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