Deck 17: Equilibrium

Question 1

Choose the correct equilibrium expression for the following reaction. A(s) + 2B(l) 3C(aq) + 4D(aq)

A)
B)
C)
D)
E) none of these

Answer 1

Question 2

At equilibrium, the concentrations of all reactants and products are constant.

Answer 2

True

Question 3

A catalyst is a substance that speeds up a reaction without being consumed.

Answer 3

True

Question 4

A minimum energy called the activation energy is needed for a reaction to occur.

Question 5

Write the equilibrium expression for the following reaction: S(s) + O₂(g) SO₂(g)

A) K =
B) K =
C) K =
D) K =
E) none of these

Question 6

At equilibrium, the concentrations of all reactants and products are equal.

Question 7

Which of the following is an example of a heterogeneous equilibrium reaction?

A) N₂O₄(g) 2NO₂(g)
B) H₂(g) + F₂(g) 2HF(g)
C) C₂H₂(g) + 2Br₂(g) C₂H₂Br₄(g)
D) N₂(g) + 3H₂(g) 2NH₃(g)
E) MgO(s) + CO₂(g) MgCO₃(s)

Question 8

The correct equilibrium expression for the reaction of sulfur dioxide gas with oxygen gas to produce sulfur trioxide gas is

A)
B)
C)
D)
E) none of these

Question 9

Write the equilibrium expression for the reaction
3O₂(g) 2O₃(g)

Question 10

For the reaction F₂(g) 2F(g)
At a particular temperature, the concentrations at equilibrium were observed to be [F₂] = 2.0 *10^-2 mol/L and [F] = 2.0 * 10^-4 mol/L. Calculate the value of the equilibrium constant from these data. (The units are deleted.)

A)
B) 1.7
C) 5.0 * 10⁵
D) 2.0 * 10^-6
E) none of these

Question 11

The ____________ model explains why a reaction proceeds faster if the concentrations of the reacting molecules are increased.

A) atomic
B) gas law
C) collision
D) Lewis dot
E) none of these

Question 12

Consider the reaction 2H₂(g) + O₂(g) 2H₂O(g) at some equilibrium position. Using the following choices, indicate what will happen if the changes below are made.

Some H₂(g) is removed from the reaction vessel.

A) shifts to the left
B) shifts to the right
C) no change

Question 13

Consider the equilibrium shown here: CaCO₃(s) CaO(s) + CO₂(g)
What would happen to the system if the total pressure were increased by adding CO₂(g)?

A) Nothing would happen.
B) More CO₂(g) would be produced.
C) The amount of CaO would increase.
D) The amount of CaCO₃ would increase.
E) Equilibrium would shift to the right.

Question 14

Given the reaction A(g) + B(g) C(g) + D(g). You have the gases A, B, C, and D at equilibrium. Upon adding gas A, the value of K

A) increases because when A is added, more products are made, increasing the product-to-reactant ratio
B) decreases because A is a reactant, so 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

Question 15

Consider the equilibrium shown here: CaCO₃(s) CaO(s) + CO₂(g)
What would happen to the system if the total pressure were increased by adding Ar(g)?

A) Nothing would happen.
B) More CO₂(g) would be produced.
C) The amount of CaO would increase.
D) The amount of CaCO₃ would increase.
E) Equilibrium would shift to the right.

Question 16

Consider the reaction 2H₂(g) + O₂(g) 2H₂O(g) at some equilibrium position. Using the following choices, indicate what will happen if the changes below are made.

Additional H₂O(g) is injected into the reaction vessel.

A) shifts to the left
B) shifts to the right
C) no change

Question 17

For the reaction 2NO(g) + O₂(g) 2NO₂(g)
At a certain temperature, the equilibrium concentrations were found to be [NO₂] = 2.6 *10^-3 M, [O₂]= 1.0 *10^-2 M, and [NO] = 2.0 * 10^-3 M. Calculate the value of the equilibrium constant from these data (delete units).

A) 1.7 * 10²
B) 6.5 * 10⁴
C) 1.3 *10²
D) 5.9 * 10^-3
E) none of these

Question 18

Consider the general reaction aA + bB cC + dD
Choose the correct equilibrium expression below.

A)
B)
C)
D)
E)

Question 19

Which of the following is an example of a homogeneous equilibrium reaction?

A) 2CO(g) + O₂(g) 2CO₂(g)
B) PCl₅(s) PCl₃(l) + Cl₂(g)
C) 2KClO₃(s) 2KCl(s) + 3O₂(g)
D) CaCO₃(s) CaO(s) + CO₂(g)
E) 6CO₂(g) + 6H₂O(g) C₆H₁₂O₆(s) + 6O₂(g)

Question 20

Consider the equilibrium shown here: CaCO₃(s) CaO(s) + CO₂(g)
What would happen to the system if more CaCO₃ were added?

A) More CaO would be produced.
B) The concentration of CO₂(g) would decrease.
C) The amount of CaCO₃ would decrease.
D) The pressure would increase.
E) Nothing would happen.

Question 21

Consider the following equilibrium: 2H₂(g) + X₂(g) 2H₂X(g) + energy
Addition of X₂ to this system at equilibrium

A) will cause [H₂] to decrease
B) will cause [X₂] to increase
C) will cause [H₂X] to increase
D) will have no effect
E) cannot possibly be carried out

Question 22

Given the equation A(g) B(g) + 2C(g). At a particular temperature, K = 1.4 *10⁵.

-Which of the following is true when the equilibrium constant for a reaction is relatively large?

A) It will take a short time to reach equilibrium.
B) It will take a long time to reach equilibrium.
C) The equilibrium lies to the left.
D) The equilibrium lies to the right.
E) two of these

Question 23

Consider the following equilibrium: H₂(g) + I₂(s) 2HI(g)
The equilibrium expression is

A)
B)
C)
D)
E)

Question 24

Given the equation A(g) B(g) + 2C(g). At a particular temperature, K = . If you mixed 1.4 mol B, 0.050 mol C, and 0.0050 mol A in a 1-liter container, in which direction would the reaction initially proceed?

A) The reaction will proceed to the right.
B) The reaction will proceed to the left.
C) The mixture is at equilibrium.
D) More information is needed to answer the question.

Question 25

Consider the following equilibrium: 2H₂(g) + X₂(g) 2H₂X(g) + energy
The equilibrium expression is

A)
B)
C)
D)
E) none of these

Question 26

Consider the following equilibrium: 2H₂(g) + X₂(g) 2H₂X(g) + energy
Decreasing the volume of the container for this system at equilibrium will cause

A) an increase in the amount of H₂X
B) an increase in the amounts of H₂ and X₂
C) an increase in the amount of H₂ but not X₂
D) no change
E) X₂ to dissociate

Question 27

Consider the reaction 2H₂(g) + O₂(g) 2H₂O(g) at some equilibrium position. Using the following choices, indicate what will happen if the changes below are made.

Some He(g) is injected into the reaction vessel.

A) shifts to the left
B) shifts to the right
C) no change

Question 28

The concentrations of pure solids or pure liquids involved in a chemical reaction are not included in the equilibrium expression for the reaction.

Question 29

Given the equation A(g) B(g) + 2C(g). At a particular temperature, K = 1.4 *10⁵.

-Placing the equilibrium mixture in an ice bath (thus lowering the temperature)

A) will cause [A] to increase
B) will cause [B] to increase
C) will have no effect
D) cannot be determined
E) none of the above

Question 30

Consider the reaction system CH₄(g) + 2O₂(g) CO₂(g) + 2H₂O(g) + energy, and use the following choices to describe what happens when the changes below are made to the system at equilibrium.

O₂(g) is removed from the reaction vessel.

A) shifts to the left
B) shifts to the right
C) no change

Question 31

Consider the reaction system CH₄(g) + 2O₂(g) CO₂(g) + 2H₂O(g) + energy, and use the following choices to describe what happens when the changes below are made to the system at equilibrium.

He(g) is added to the reaction vessel.

A) shifts to the left
B) shifts to the right
C) no change

Question 32

Consider the reaction system CH₄(g) + 2O₂(g) CO₂(g) + 2H₂O(g) + energy, and use the following choices to describe what happens when the changes below are made to the system at equilibrium.

CH₄(g) is added to the reaction vessel.

A) shifts to the left
B) shifts to the right
C) no change

Question 33

Consider the following equilibrium: 2H₂(g) + X₂(g) 2H₂X(g) + energy
Addition of argon to this system at equilibrium

A) will cause [H₂] to decrease
B) will cause [X₂] to increase
C) will cause [H₂X] to increase
D) will have no effect
E) cannot possibly be carried out

Question 34

Given the equation A(g) B(g) + 2C(g). At a particular temperature, K = 1.4 *10⁵.

-Raising the pressure by decreasing the volume of the container

A) will cause [A] to increase
B) will cause [B] to increase
C) will have no effect
D) cannot be determined
E) none of the above

Question 35

Consider the reaction 2H₂(g) + O₂(g) 2H₂O(g) at some equilibrium position. Using the following choices, indicate what will happen if the changes below are made.

The size of the reaction vessel is decreased.

A) shifts to the left
B) shifts to the right
C) no change

Question 36

In the presence of ultraviolet light, the "inert" gas xenon (Xe) will react with fluorine (F₂) gas to produce solid XeF₄. What is the equilibrium expression for this reaction?

A)
B)
C)
D)
E)

Question 37

Consider the reaction system CH₄(g) + 2O₂(g) CO₂(g) + 2H₂O(g) + energy, and use the following choices to describe what happens when the changes below are made to the system at equilibrium.

CO₂(g) is removed from the reaction vessel.

A) shifts to the left
B) shifts to the right
C) no change

Question 38

Consider a system of four gases. The equilibrium concentration of each product is 2.8 M. The equilibrium concentrations of the reactants are equal. The equilibrium is shown here: A + B C + D K = 2.6
What is the equilibrium concentration of gas A?

A) 3.0 M
B) 20.4 M
C) 7.3 M
D) 1.7 M
E) 0.58 M

Question 39

Consider the reaction system CH₄(g) + 2O₂(g) CO₂(g) + 2H₂O(g) + energy, and use the following choices to describe what happens when the changes below are made to the system at equilibrium.

The temperature is increased.

A) shifts to the left
B) shifts to the right
C) no change

Question 40

Given the equation A(g) B(g) + 2C(g). At a particular temperature, K = 1.4 *10⁵.

-Addition of chemical B to an equilibrium mixture of the above

A) will cause [A] to increase
B) will cause [C] to increase
C) will have no effect
D) cannot be determined
E) none of the above

Question 41

The solubility of BaCO₃(s) in water at a certain temperature is 4.4*10^-5 mol/L. Calculate the value of K_sp for BaCO₃(s) at this temperature.

A) 4.4 * 10^-5
B) 8.8 * 10^-5
C) 1.9* 10^-9
D) 6.6 * 10^-3
E) none of these

Question 42

Calculate the concentration of the copper ion is a saturated solution of copper(I) cyanide, CuCN (K_sp = ).

A)
B)
C)
D)
E) none of these

Question 43

The solubility of ZnS(s) in water at a certain temperature is 1.7 * 10^-11 mol/L. The value of the K_sp of ZnS is

A) 2.9 * 10^-22
B) 1.7 * 10^-11
C) 4.1 * 10^-6
D) 8.5 *10^-12
E) 3.4 * 10^-11

Question 44

Write the balanced equation for the dissolving of Ag₂S(s) in water.

Question 45

Write the balanced equation for the dissolving of Fe₃(PO₄)₂ in water.

Question 46

Lithium carbonate, Li₂CO₃ has a K_sp of at a certain temperature. What is the solubility in mol/L for Li₂CO₃ at this temperature?

A)
B)
C)
D)
E)

Question 47

Write the balanced equation for the dissolving of PbCl₂(s) in water.

Question 48

Given the solubility products (K_sp) BaSO₄
1.5* 10^-9
CoS
5.0 * 10^-22
PbSO₄
1.3 *10^-2
AgBr
5.0 * 10^-13
Which of the following compounds is the most soluble (in mol/L)?

A) BaSO₄
B) CoS
C) PbSO₄
D) AgBr
E) BaCO₃

Question 49

The K_sp for ZnS(s) is 3.0 *10^-22 at a certain temperature. The solubility of ZnS(s) in water at this temperature is

A)
B)
C)
D)
E) none of these

Question 50

The solubility in mol/L of Ag₂CrO₄ is 1.3 F* 10^-4 M at a certain temperature. What is the K_sp for this compound?

A) 1.3 * 10^-4
B) 2.2 *10^-12
C) 8.8 *10^-12
D) 3.4 *10^-8
E) 6.8*10^-8

Question 51

The solubility of Mg(OH)₂(s) in water at a certain temperature is 1.1 *10^-4 mol/L. Calculate the value of K_sp for Mg(OH)₂(s) at this temperature.

A)
B)
C)
D)
E) none of these

Question 52

For the reaction 2SO₂(g) + O₂(g) 2SO₃(g)
At a certain temperature, the equilibrium concentrations were observed to be [SO₂] = 0.564 M, [O₂] = 7.50*10^-2 M, and [SO₃] = 0.650 M. Calculate the value of K for this system at this temperature.

A) 15.4
B) 27.2
C) 9.99
D) 236
E) 17.7

Question 53

The solubility of Co(OH)₂ in water at a certain temperature is mol/L. The value of K_sp of Co(OH)₂ at this temperature is

A)
B)
C)
D)
E) none of these

Question 54

For the reaction CO(g) + H₂O(g) CO₂(g) + H₂(g)
K = 3.88 at a certain temperature. If at this temperature in a certain experiment the equilibrium concentrations are [H₂] = 1.5 M, [CO₂] = 1.8 M, and [H₂O] = 0.26 M, calculate [CO].

A) 0.37 M
B) 1.5 M
C) 4.7 M
D) 2.7 M
E) none of these

Question 55

The solubility of Cd(OH)₂ in water at a certain temperature is 1.9 *10^-5 mol/L. The K_sp value for Cd(OH)₂ is

A) 2.7 * 10^-14
B) 1.9 *10^-5
C) 6.9 * 10^-15
D) 7.2* 10^-10
E) 3.6 * 10^-10

Question 56

The molar solubility of PbI₂ at a certain temperature is 1.7 *10^-3 M. Calculate the value of K_sp for PbI₂.

A)
B)
C)
D)
E) none of these