Question 1

Which of the following is true for a chemical reaction at equilibrium?

Accepted Answer

A)   only the forward reaction stops
B)   only the reverse reaction stops
C)   both the forward and reverse reactions stop
D)   the rate constants for the forward and reverse reactions are equal
E)   the rates of the forward and reverse reactions are equalF) A) and B)
G) C) and D)

Question 2

Which of the following can be predicted from the law of mass action?
I. At equilibrium, the ratio of concentrations of products to reactants, each raised to a power corresponding to the stoichiometric coefficient in the balanced reaction equation, will have a constant value at a given temperature.
II. The direction of the reaction given values for the reactant and product concentrations and the equilibrium constant.
III. The amounts of products that can be produced from a given amount of reactants.

Accepted Answer

A)   I only
B)   II and III
C)   I, II, and III
D)   I and II
E)   I and IIIF) A) and E)
G) A) and D)

Question 3

Water can decompose at an elevated temperature to give hydrogen and oxygen according to the equation below. At a particular temperature in a vessel containing water vapor and air, the partial pressures of H2O, H2, and O2 are 0.055 atm, 0.0065 atm, and 0.19 atm, respectively. What is the value of the reaction quotient, QP, for this reaction under these conditions?
2H2O(g)   ⇆\leftrightarrows⇆  2H2(g)  + O2(g)

Accepted Answer

A)   0.023
B)   1.5 *10-4
C)   2.7 *10-3
D)   370
E)   4.4 * 104 F) C) and D)
G) B) and C)

Question 4

Carbon dioxide and argon, which is a noble or inert gas, are placed in a vessel and heated. Equilibrium is reached at some particular temperature. Carbon dioxide dissociates by the following reaction.
2CO2(g)   ⇆\leftrightarrows⇆  2CO(g)  + O2(g) 
What is the result of increasing the pressure by adding more argon?
I. The equilibrium shifts to produce more carbon dioxide and reduce the pressure.
II. The equilibrium shifts to remove carbon dioxide and reduce the pressure.
III. The equilibrium does not change because argon is not involved in the reaction.
IV. The equilibrium does not change because the concentrations are not affected.

Accepted Answer

A)   I only
B)   II only
C)   III only
D)   IV only
E)   III and IV F) C) and E)
G) All of the above

Question 5

Consider the reaction of nitrogen and hydrogen gas under standard state conditions to form two moles of ammonia gas (NH3). Write the initial expression for Kc that would be derived from a RICE table if the concentrations of all species were as follows.
[N2] = 3 M
[H2] = 2 M
[NH3] = 1 M

Accepted Answer

Question 6

The reaction of bromine gas with chlorine gas, shown here, has a Kp value of 7.20. If a closed vessel was charged with the two reactants, each at an initial partial pressure of 0.500 atm, and the product also at 0.500 atm, what would be the equilibrium partial pressure of BrCl(g) ?
Br2(g)  + Cl2(g)   ⇆\leftrightarrows⇆  2BrCl(g)

Accepted Answer

A)   0.500 atm
B)   0.680 atm
C)   0.859 atm
D)   0.029 atm
E)   0.987 atm F) A) and D)
G) A) and C)

Question 7

Equilibrium constants for gases can be expressed in terms of concentrations, Kc, or in terms of partial pressures, Kp. Which one of the following statements regarding Kc and Kp is correct?

Accepted Answer

A)   Kc and Kp are equal when all stoichiometric coefficients in the balanced reaction equation equal one.
B)   Kc and Kp have the same values but different units.
C)   Kc and Kp are equal when the sum of the stoichiometric coefficients for the products equals the sum of the stoichiometric coefficients for the reactants.
D)   Kc and Kp can never be equal.
E)   Kc and Kp are equal when the conditions are standard (P = 1 atm, T = 298 K) .F) A) and D)
G) A) and E)

Question 8

In equilibrium expressions, the concentrations of pure solids and liquids ________

Accepted Answer

A)   have the assigned value of one.
B)   have the assigned value of zero.
C)   have constant values, cS and cl.
D)   are determined from the density and molar mass.
E)   are treated as any other solute.F) C) and D)
G) B) and D)

Question 9

Dry ice (solid carbon dioxide)  is placed in a sealed container. It sublimes to produce carbon dioxide gas and reaches equilibrium at a given temperature. If the amount of dry ice in the container is doubled, then ________.
CO2(s)   ⇆\leftrightarrows⇆  CO2(g)

Accepted Answer

A)   the amount of CO2(g)  would double.
B)   the amount of CO2(g)  would increase but not double.
C)   the partial pressure of CO2(g)  would increase.
D)   the amount of CO2(g)  would not change.
E)   the equilibrium amount of CO2(s)  would be less. F) B) and C)
G) C) and D)

Question 10

Under what conditions are the values of Kc and Kp for a given gas-phase equilibrium the same?

Accepted Answer

A)   there is no change in the moles of gas in the reaction
B)   there is no change in the temperature during the reaction
C)   if the coefficients of the reactants and products are the same
D)   if the pressure remains constant
E)   if either Kc or Kp = 1F) B) and E)
G) C) and E)

Question 11

An equilibrium that strongly favors products has ________

Accepted Answer

A)   a value of K  1.
B)   a value of K >> 1.
C)   a value of Q >> 1.
D)   a value of Q  1.
E)   K = Q.F) A) and C)
G) A) and D)

Exam 15: Chemical Equilibrium: How Much Product Does a Reaction Really Make

Correct Answer
verified

Equilibrium constants for gases can be expressed in terms of concentrations, K_c, or in terms of partial pressures, K_p. Which one of the following statements regarding K_c and K_p is correct?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Under what conditions are the values of K_c and K_p for a given gas-phase equilibrium the same?

Correct Answer
verified

Which of the following is true for a chemical reaction at equilibrium?

Correct Answer
verified

Correct Answer
verified

In equilibrium expressions, the concentrations of pure solids and liquids ________

Correct Answer
verified

An equilibrium that strongly favors products has ________

Correct Answer
verified

Consider the reaction of nitrogen and hydrogen gas under standard state conditions to form two moles of ammonia gas (NH₃). Write the initial expression for K_c that would be derived from a RICE table if the concentrations of all species were as follows. [N₂] = 3 M [H₂] = 2 M [NH₃] = 1 M

Correct Answer
verified

Dry ice (solid carbon dioxide) is placed in a sealed container. It sublimes to produce carbon dioxide gas and reaches equilibrium at a given temperature. If the amount of dry ice in the container is doubled, then ________. CO₂(s) $\leftrightarrows$ CO₂(g)

Correct Answer
verified

Exam 15: Chemical Equilibrium: How Much Product Does a Reaction Really Make

Correct AnswerverifiedShow Answer

Equilibrium constants for gases can be expressed in terms of concentrations, Kc, or in terms of partial pressures, Kp. Which one of the following statements regarding Kc and Kp is correct?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Under what conditions are the values of Kc and Kp for a given gas-phase equilibrium the same?

Correct AnswerverifiedShow Answer

Which of the following is true for a chemical reaction at equilibrium?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

In equilibrium expressions, the concentrations of pure solids and liquids ________

Correct AnswerverifiedShow Answer

An equilibrium that strongly favors products has ________

Correct AnswerverifiedShow Answer

Consider the reaction of nitrogen and hydrogen gas under standard state conditions to form two moles of ammonia gas (NH3). Write the initial expression for Kc that would be derived from a RICE table if the concentrations of all species were as follows. [N2] = 3 M [H2] = 2 M [NH3] = 1 M

Correct AnswerverifiedShow Answer

Dry ice (solid carbon dioxide) is placed in a sealed container. It sublimes to produce carbon dioxide gas and reaches equilibrium at a given temperature. If the amount of dry ice in the container is doubled, then ________. CO2(s) ⇆\leftrightarrows⇆ CO2(g)

Correct AnswerverifiedShow Answer

Correct Answer
verified

Equilibrium constants for gases can be expressed in terms of concentrations, K_c, or in terms of partial pressures, K_p. Which one of the following statements regarding K_c and K_p is correct?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Under what conditions are the values of K_c and K_p for a given gas-phase equilibrium the same?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Consider the reaction of nitrogen and hydrogen gas under standard state conditions to form two moles of ammonia gas (NH₃). Write the initial expression for K_c that would be derived from a RICE table if the concentrations of all species were as follows. [N₂] = 3 M [H₂] = 2 M [NH₃] = 1 M

Correct Answer
verified

Dry ice (solid carbon dioxide) is placed in a sealed container. It sublimes to produce carbon dioxide gas and reaches equilibrium at a given temperature. If the amount of dry ice in the container is doubled, then ________. CO₂(s) $\leftrightarrows$ CO₂(g)

Correct Answer
verified