Deck 13: Chemical Equilibrium

Question 1

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.

Answer 1

I,II

Question 2

Determine the equilibrium constant for the system N₂O₄ 2NO₂ at 25°C.The concentrations are shown here: [N₂O₄] = 2.32 $\times$ 10^-2 M,[NO₂] = 1.41 $\times$ 10^-2 M.

A)0.608
B)1.65
C)1.17 $\times$ 10²
D)0.369
E)8.57 $\times$ 10^-3

Answer 2

8.57 $\times$ 10^-3

Question 3

Apply the law of mass action to determine the equilibrium expression for 2NO₂Cl(aq) 2NO₂(aq)+ Cl₂(aq).

A)K = 2[NO₂][Cl₂]/2[NO₂Cl]
B)K = 2[NO₂Cl]/2[NO₂][Cl₂]
C)K = [NO₂Cl]²/[NO₂]²[Cl₂]
D)K = [NO₂]²[Cl₂]/[NO₂Cl]²
E)K = [NO₂Cl]²[NO₂]²[Cl₂]

Answer 3

K = [NO₂]²[Cl₂]/[NO₂Cl]²

Question 4

For the reaction N₂O₄(g) 2NO₂(g),K_p = 0.148 at a temperature of 298 K.What is K_p for the following reaction? 10NO₂(g) 5N₂O₄(g)

A)6.76
B)0.74
C)1.35
D)1.41 $\times$ 10⁴
E)7.10 $\times$ 10^-5

Question 5

If,at a given temperature,the equilibrium constant for the reaction H₂(g)+ Cl₂(g) 2HCl(g)is K_p,then the equilibrium constant for the reaction HCl(g) $\to$ H₂(g)+ Cl₂ (g)can be represented as:

A)
B)K_p²
C)
D)
E)none of these

Question 6

Which of the following is true about chemical equilibrium?

A)It is microscopically and macroscopically static.
B)It is microscopically and macroscopically dynamic.
C)It is microscopically static and macroscopically dynamic.
D)It is microscopically dynamic and macroscopically static.
E)None of these are true about chemical equilibrium.

Question 7

Equilibrium is reached in chemical reactions when:

A)The rates of the forward and reverse reactions become equal.
B)The concentrations of reactants and products become equal.
C)The temperature shows a sharp rise.
D)All chemical reactions stop.
E)The forward reaction stops.

Question 8

Given the equilibrium constants for the following reactions: 4Cu(s)+ O₂(g) 2Cu₂O(s),K₁
2CuO(s) Cu₂O(s)+ O₂(g),K₂
What is K for the system
2Cu(s)+ O₂(g) 2CuO(s)
Equivalent to?

A)(K₁)(K₂)
B)
C)
D)
E)

Question 9

Consider the chemical system CO + Cl₂ COCl₂;K = 4.6 $\times$ 10⁹ L/mol.

-If the concentration of the product were to double,what would happen to the equilibrium constant?

A)It would double its value.
B)It would become half its current value.
C)It would quadruple its value.
D)It would not change its value.
E)It would depend on the initial conditions of the product.

Question 10

For the reaction H₂(g)+ Cl₂(g) 2HCl(g),K_c = 1.22 $\times$ 10³³ at a temperature of 301 K.What is K_p at this temperature?

A)1.22 $\times$ 10³³
B)3.01 $\times$ 10³⁴
C)4.93 $\times$ 10³¹
D)7.43 $\times$ 10³⁵
E)2.00 $\times$ 10³⁰

Question 11

Consider the gaseous reaction CO(g)+ Cl₂(g) COCl₂(g).What is the expression for K_p in terms of K?

A)K(RT)
B)K/(RT)
C)K(RT)²
D)K/(RT)²
E)1/K(RT)

Question 12

For a particular system at a particular temperature there ______ equilibrium constant(s)and there _______ equilibrium position(s).

A)are infinite;is one
B)is one;are infinite
C)is one;is one
D)are infinite;are infinite
E)none of these

Question 13

At a given temperature,K = 0.017 for the equilibrium: PCl₅(g) PCl₃(g)+ Cl₂(g)
What is K for:
Cl₂(g)+ PCl₃(g) PCl₅(g)?

A)0.017
B)59
C)0.00029
D)17
E)3500

Question 14

For the reaction given below,2.00 moles of A and 3.00 moles of B are placed in a 6.00-L container. At equilibrium,the concentration of A is 0.246 mol/L.What is the concentration of B at equilibrium?

A)0.246 mol/L
B)0.325 mol/L
C)0.500 mol/L
D)0.492 mol/L
E)none of these

Question 15

Indicate the mass action expression for the following reaction: 2X(g)+ Y(g) 3W(g)+ V(g)

A)[X]²[Y][W]³[V]
B)
C)
D)
E)none of these

Question 16

Which expression correctly describes the equilibrium constant for the following reaction? 4NH₃(g)+ 5O₂(g) 4NO(g)+ 6H₂O(g)

A)K = ( 4NH₃] + 5[O₂] )/ ( 4[NO] + 6[H₂O] )
B)K = ( 4[NO] + 6[H₂O] )/ (4NH₃] + 5[O₂] )
C)K = ( [NO][H₂O] )/ ( [NH₃][O₂] )
D)K = ( [NO]⁴[H₂O]⁶ )/ ( [[NH₃]⁴[O₂]⁵ )
E)K = ( [NH₃]⁴[O₂]⁵ )/ ( [NO]⁴[H₂O]⁶ )

Question 17

Which of the following is true about a system at equilibrium?

A)The concentration(s)of the reactant(s)is equal to the concentration(s)of the product(s).
B)No new product molecules are formed.
C)The concentration(s)of reactant(s)is constant over time.
D)The rate of the reverse reaction is equal to the rate of the forward reaction and both rates are equal to zero.
E)None of the above (A-D)is true.

Question 18

If the equilibrium constant for A + B C is 0.208,then the equilibrium constant for 2C 2A + 2B is

A)0.584
B)4.81
C)0.416
D)23.1
E)0.208

Question 19

Consider the chemical system CO + Cl₂ COCl₂;K = 4.6 $\times$ 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.

Question 20

If K = 0.144 for A₂ + 2B 2AB,then for 4AB 2A₂ + 4B,K would equal:

A)0.288
B)0.144
C)-0.144
D)3.47
E)48.2

Question 21

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 N₂(g)+ O₂(g) 2NO(g)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.

Question 22

A 1-L container originally holds 0.4 mol of N₂,0.1 mol of O₂,and 0.08 mole of NO.If the volume of the container holding the equilibrium mixture of N₂,O₂,and NO is decreased to 0.5 L without changing the quantities of the gases present,how will their concentrations change?

A)The concentration of NO will increase;the concentrations of N₂ and O₂ will decrease.
B)The concentrations of N₂ and O₂ will increase;and the concentration of NO will decrease.
C)The concentrations of N₂,O₂,and NO will increase.
D)The concentrations of N₂,O₂,and NO will decrease.
E)There will be no change in the concentrations of N₂,O₂,and NO.

Question 23

Consider the reaction: CaCl₂(s)+ 2H₂O(g) CaCl₂·2H₂O(s)
The equilibrium constant for the reaction as written is:

A)K =
B)
C)
D)K = [H₂O]²
E)K =

Question 24

Consider the following reaction: CS₂(g)+ 4H₂(g) CH₄(g)+ 2H₂S(g).The equilibrium constant K is about 0.31 at 900.°C.What is K_p at this temperature?

A)2.9 $\times$ 10³
B)3.2 $\times$ 10^-3
C)3.3 $\times$ 10^-5
D)3.0 $\times$ 10¹
E)1.1 $\times$ 10^-3

Question 25

For the reaction given below,2.00 moles of A and 3.00 moles of B are placed in a 6.00-L container. A(g)+ 2B(g) C(g)
At equilibrium,the concentration of A is 0.213 mol/L.What is the value of K?

A)2.18
B)1.79
C)0.213
D)8.40
E)0.565

Question 26

Given the equation 2NOCl₂(g) 2NO(g)+ Cl₂(g),the equilibrium constant is about 0.0196 at 115°C.Calculate K_p.

A)0.0196
B)0.624
C)0.185
D)19.9
E)none of these

Question 27

Find the value of the equilibrium constant (K)(at 500 K)for N₂(g)+ 3H₂(g) 2NH₃(g).The value for K_p at 500 K is 1.5 $\times$ 10^-5/atm².

A)7.5 $\times$ 10^-2
B)1.3 $\times$ 10^-2
C)9.6 $\times$ 10^-2
D)2.5 $\times$ 10^-2
E)6.0 $\times$ 10^-2

Question 28

Consider the reaction: 2SO₂(g)+ O₂(g) 2SO₃(g)at constant temperature.Initially a container is filled with pure SO₃(g)at a pressure of 2 atm,after which equilibrium is reached.If y is the partial pressure of O₂ at equilibrium,the value of K_p is:

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

Question 29

Calculate K_p for using the following data: K_p = 2.3 $\times$ 10⁶ K_p = 1.8 $\times$ 10³⁷

A)4.1 $\times$ 10⁴³
B)2.1 $\times$ 10⁴³
C)2.9 $\times$ 10^-25
D)5.4 $\times$ 10^-13
E)9.8 $\times$ 10^-13

Question 30

Consider the reaction At 1273 K,the K_p value is 167.5.What is the at equilibrium if the is 0.17 atm at this temperature?

A)2.7 atm
B)0.085 atm
C)11 atm
D)5.3 atm
E)7.5 atm

Question 31

Consider the following equilibrated system: 2NO₂(g) 2NO(g)+ O₂(g).If the K_p value is 0.604,find the equilibrium pressure of the O₂ gas if the NO₂ gas pressure is 0.520 atm and the P_NO is 0.300 atm at equilibrium.

A)1.05 atm
B)24.8 atm
C)0.348 atm
D)0.201 atm
E)1.81 atm

Question 32

Consider the reaction H₂ + I₂ 2HI for which K = 44.8 at a high temperature.If an equimolar mixture of reactants gives the concentration of the product to be 0.50 M at equilibrium,determine the equilibrium concentration of the hydrogen.

A)1.1 $\times$ 10^-1 M
B)7.5 $\times$ 10^-2 M
C)3.7 $\times$ 10^-2 M
D)1.3 $\times$ 10¹ M
E)5.6 $\times$ 10^-3 M

Question 33

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

A)
B)
C)
D)
E)

Question 34

The reaction quotient for a system is 7.2 $\times$ 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.

Question 35

For the reaction NO(g)+ O₂(g) NO₂(g)at 750°C,the equilibrium constant K_c equals:

A)1.0
B)K_p
C)
D)
E)

Question 36

Which of the following is true for a system whose equilibrium constant is relatively small?

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 37

A 10.0-g sample of solid NH₄Cl is heated in a 5.00-L container to 900.°C.At equilibrium the pressure of NH₃(g)is 1.51 atm. NH₄Cl(s) NH₃(g)+ HCl(g)
The equilibrium constant,K_p,for the reaction is:

A)1.51
B)2.28
C)3.02
D)8.21
E)none of these

Question 38

An equilibrium reaction,A₂(g)+ 3B₂(g) 2C(g),has a K_p at 225°C of 2.6 $\times$ 10^-3 /atm².What is K for this reaction at that temperature?

A)1.6 $\times$ 10^-6
B)7.6 $\times$ 10^-6
C)4.3
D)6.4 $\times$ 10^-5
E)0.89

Question 39

Consider the following reaction: 2HF(g) H₂(g)+ F₂(g)(K = 1.00 10^-2)
Given 1.00 mole of HF(g),0.362 mole of H₂(g),and 0.750 mole of F₂(g)are mixed in a 5.00 L flask,determine the reaction quotient,Q.

A)Q = 0.0543
B)Q = 0.272
C)Q = 0.0679
D)Q = 2.11
E)none of these

Question 40

Which of the following statements about the equilibrium is false?

A)If the system is heated,the right side is favored.
B)This is a heterogeneous equilibrium.
C)If the pressure on the system is increased by changing the volume,the left side is favored.
D)Adding more H₂(g)increases the equilibrium constant.
E)Removing HI as it forms forces the equilibrium to the right.

Question 41

Consider the following reaction (assume an ideal gas mixture): 2NOBr(g) 2NO(g)+ Br₂(g)A 1.0-liter vessel was initially filled with pure NOBr,at a pressure of 4.0 atm,at 300 K.
After equilibrium was established,the partial pressure of NOBr was 3.1 atm.What is K_p for the reaction?

A)0.26
B)0.038
C)0.13
D)0.45
E)none of these

Question 42

Raising the pressure by lowering the volume of the container will

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

Question 43

Carbon disulfide and chlorine react according to the following equation: CS₂(g)+ 3Cl₂(g) S₂Cl₂(g)+ CCl₄(g)
When 2.14 mol of CS₂ and 5.85 mol of Cl₂ are placed in a 2.00-L container and allowed to come to equilibrium,the mixture is found to contain 0.620 mol of CCl₄.How many moles of Cl₂ are present at equilibrium?

A)1.520 mol
B)0.620 mol
C)3.99 mol
D)4.61 mol
E)2.00 mol

Question 44

The reaction: H₂(g)+ I₂(g) 2HI(g)
Has K_p = 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 0.213 atm.What is the partial pressure of I₂?

A)0.213 atm
B)0.409 atm
C)1.64 atm
D)10.9 atm
E)75.1 atm

Question 45

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 2.2 atm.Calculate the partial pressure of hydrogen gas at equilibrium.

A)2.2 atm
B)0.80 atm
C)1.4 atm
D)0.0 atm
E)none of these

Question 46

A sample of solid NH₄NO₃ was placed in an evacuated container and then heated so that it decomposed explosively according to the following equation: NH₄NO₃(s) N₂O(g)+ 2H₂O(g)
At equilibrium the total pressure in the container was found to be 2.63 atm at a temperature of 500.°C.Calculate K_p.

A)0.769
B)1.54
C)0.674
D)2.70
E)72.8

Question 47

Consider the equation A(aq)+ 2B(aq) 3C(aq)+ 2D(aq).In one experiment,45.0 mL of 0.050 M A is mixed with 25.0 mL 0.100 M B.At equilibrium the concentration of C is 0.0410 M.Calculate K.

A)7.3
B)0.34
C)0.040
D)0.14
E)none of these

Question 48

A 3.00-liter flask initially contains 3.00 mol of gas A and 1.50 mol of gas B.Gas A decomposes according to the following reaction: 3A 2B + C
The equilibrium concentration of gas C is 0.119 mol/L.Determine the equilibrium concentration of gas B.

A)0.119 M
B)0.619 M
C)0.738 M
D)0.262 M
E)0.238 M

Question 49

Consider the following reaction (assume an ideal gas mixture): 2NOBr(g) 2NO(g)+ Br₂(g)A 1.0-liter vessel was initially filled with pure NOBr,at a pressure of 4.0 atm,at 300 K.
After equilibrium was reached,the volume was increased to 2.0 liters,while the temperature was kept at 300 K.The result of this change was

A)an increase in K_p
B)a decrease in K_p
C)a shift in the equilibrium position to the right
D)a shift in the equilibrium position to the left
E)none of these

Question 50

Consider the following equilibrium: 2NOCl(g) 2NO(g)+ Cl₂(g)with K = 1.6 $\times$ 10^-5.In an experiment,1.00 mole of pure NOCl and 1.00 mole of pure Cl₂ are placed in a 1.00-L container.

-If x moles of NOCl react,what is the equilibrium concentration of NO?

A)x
B)2x
C)-x
D)-2x
E)x²

Question 51

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

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

Question 52

At a higher temperature,K = 1.8 $\times$ 10^-5.Placing the equilibrium mixture in an ice bath (thus lowering the temperature)will

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

Question 53

Initially 2.0 moles of N₂(g)and 4.0 moles of H₂(g)were added to a 1.0-liter container and the following reaction then occurred: 3H₂(g)+ N₂(g) 2NH₃(g)
The equilibrium concentration of NH₃(g)= 0.55 moles/liter at 700.°C.The value for K at 700.°C for the formation of ammonia is:

A)1.0 $\times$ 10^-1
B)5.5 $\times$ 10^-2
C)5.5 $\times$ 10^-3
D)3.0 $\times$ 10^-1
E)none of these

Question 54

A mixture of nitrogen and hydrogen was allowed to come to equilibrium at a given temperature. 3H₂ + N₂ 2NH₃
An analysis of the mixture at equilibrium revealed 2.1 mol N₂,3.2 mol H₂,and 1.8 mol NH₃.How many moles of H₂ were present at the beginning of the reaction?

A)3.2
B)4.8
C)5.0
D)5.9
E)4.4

Question 55

Given the equation 2A(g) 2B(g)+ C(g).At a particular temperature,K = 1.6 $\times$ 10⁴.

-If you mixed 5.0 mol B,0.10 mol C,and 0.0010 mol A in a one-liter container,which direction would the reaction initially proceed?

A)To the left.
B)To the right.
C)The above mixture is the equilibrium mixture.
D)Cannot tell from the information given.
E)None of these (A-D).

Question 56

A 3.00-liter flask initially contains 3.00 mol of gas A and 1.50 mol of gas B.Gas A decomposes according to the following reaction: 3A 2B + C
The equilibrium concentration of gas C is 0.115 mol/L.Determine the equilibrium concentration of gas A.

A)0.115 M
B)0.655 M
C)0.730 M
D)0.885 M
E)0.345 M

Question 57

A 3.00-liter flask initially contains 3.00 mol of gas A and 1.50 mol of gas B.Gas A decomposes according to the following reaction: 3A 2B + C
The equilibrium concentration of gas C is 0.146 mol/L.Determine the value of the equilibrium constant,K.

A)0.206
B)0.163
C)3.84 $\times$ 10^-3
D)0.516
E)none of these

Question 58

For the equilibrium system: CO₂(g)+ H₂(g) CO(g)+ H₂O(g) H = +42 kJ/mol
K equals 1.6 at 1260 K.If 0.15 mol each of CO₂,H₂,CO,and H₂O (all at 1260 K)were placed in a 1.0-L thermally insulated vessel that was also at 1260 K,then as the system came to equilibrium:

A)The temperature would decrease and the mass of CO₂ would increase.
B)The temperature would decrease and the mass of CO₂ would decrease.
C)The temperature would remain constant and the mass of CO₂ would increase.
D)The temperature would increase and the mass of CO₂ would increase.
E)The temperature would increase and the mass of CO₂ would decrease.

Question 59

CS₂(g)+ 3Cl₂(g) CCl₄(g)+ S₂Cl₂(g) At a given temperature,the reaction above is at equilibrium when [CS₂] = 0.050 M,[Cl₂] = 0.25 M,[CCl₄] = 0.15 M,and [S₂Cl₂] = 0.35 M.What would be the direction of the reaction when the reactants and products have the following concentrations: CS₂ = 0.15 M,Cl₂ = 0.18 M,CCl₄ = 0.29 M,and S₂Cl₂ = 0.21 M?

A)to the right
B)to the left
C)no change
D)cannot predict unless we know the temperature
E)cannot predict unless we know whether the reaction is endothermic or exothermic

Question 60

The following reaction is investigated (assume an ideal gas mixture): 2N₂O(g)+ N₂H₄(g) 3N₂(g)+ 2H₂O(g)
Initially there are 0.10 moles of N₂O and 0.25 moles of N₂H₄,in a 10.0-L container.If there are 0.048 moles of N₂O at equilibrium,how many moles of N₂ are present at equilibrium?

A)2.6 $\times$ 10^-2
B)5.2 $\times$ 10^-2
C)7.8 $\times$ 10^-2
D)1.6 $\times$ 10^-1
E)none of these

Question 61

The following questions refer to the equilibrium shown here: 4NH₃(g)+ 5O₂(g) 4NO(g)+ 6H₂O(g)
What would happen to the system if oxygen were added?

A)More ammonia would be produced.
B)More oxygen would be produced.
C)The equilibrium would shift to the right.
D)The equilibrium would shift to the left.
E)Nothing would happen.

Question 62

The equilibrium system 2A 2B + C has a very small equilibrium constant: K = 2.6 $\times$ 10^-6. Initially 3.0 moles of A are placed in a 1.5-L flask.Determine the concentration of C at equilibrium.

A)0.011 M
B)0.024 M
C)0.032 M
D)0.048 M
E)2.0 M

Question 63

The questions below refer to the following system:
Co(H₂O)₆²⁺ + 4 Cl^- CoCl₄^2- + 6H₂O
(pink)
(blue)
When cobalt(II)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.
Which statement below describes the change that the system will undergo if water is added?

A)More chloride ions will be produced.
B)More water will be produced.
C)The equilibrium will shift to the right.
D)The color will become more blue.
E)There will be less of the hydrated cobalt ion at the new equilibrium position.

Question 64

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.

Question 65

For a certain reaction at 25.0°C,the value of K is 1.2 $\times$ 10^-3.At 50.0°C the value of K is 3.4 $\times$ 10^-1.This means that the reaction is

A)exothermic
B)endothermic
C)never favorable
D)more information needed
E)none of these (A-D)

Question 66

At a certain temperature K for the reaction 2NO₂ N₂O₄ is 7.5 liters/mole.If 2.0 moles of NO₂ are placed in a 2.0-liter container and permitted to react at this temperature,calculate the concentration of N₂O₄ at equilibrium.

A)0.39 moles/liter
B)0.65 moles/liter
C)0.82 moles/liter
D)7.5 moles/liter
E)none of these

Question 67

Consider the following equilibrium: 2NOCl(g) 2NO(g)+ Cl₂(g)
With K = 1.6 $\times$ 10^-5.1.00 mole of pure NOCl and 0.964 mole of pure Cl₂ are placed in a 1.00-L container.Calculate the equilibrium concentration of Cl₂(g).

A)1.6 $\times$ 10^-5 M
B)0.966 M
C)0.483 M
D)2.04 $\times$ 10^-3 M
E)4.07 $\times$ 10^-3 M

Question 68

Ammonia is prepared industrially by the reaction: N₂(g)+ 3H₂(g) 2NH₃(g)for the reaction: $\Delta$ H° = -92.2 kJ and K (at 25°C)= 4.0 $\times$ 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 the above is true.

Question 69

At 500.0 K,one mole of gaseous ONCl is placed in a one-liter container.At equilibrium it is 5.3% dissociated according to the equation shown here: 2ONCl 2NO + Cl₂.Determine the equilibrium constant.

A)8.3 $\times$ 10^-5
B)1.6 $\times$ 10^-3
C)5.6 $\times$ 10^-2
D)9.5 $\times$ 10^-1
E)1.2 $\times$ 10⁴

Question 70

For the reaction below,K_p = 1.16 at 800.°C. CaCO₃(s) CaO(s)+ CO₂(g)
If a 31.3-gram sample of CaCO₃ is put into a 10.0-L container and heated to 800.°C,what percent of the CaCO₃ will react to reach equilibrium?

A)21.8%
B)42.1%
C)56.5%
D)100.0%
E)none of these

Question 71

Consider the following equilibrium: 2NOCl(g) 2NO(g)+ Cl₂(g)with K = 1.6 $\times$ 10^-5.In an experiment,1.00 mole of pure NOCl and 1.00 mole of pure Cl₂ are placed in a 1.00-L container.

-If x moles of NOCl react,what is the equilibrium concentration of Cl₂?

A)x
B) x
C)1 + x
D)1 + x
E)1 + 2x

Question 72

Consider the following equilibrium: 2NOCl(g) 2NO(g)+ Cl₂(g)
With K = 1.6 $\times$ 10^-5.1.00 mole of pure NOCl and 0.958 mole of pure Cl₂ are placed in a 1.00-L container.Calculate the equilibrium concentration of NO(g).

A)2.04 $\times$ 10^-3 M
B)9.58 $\times$ 10^-1 M
C)1.04 M
D)5.78 $\times$ 10^-3 M
E)4.09 $\times$ 10^-3 M

Question 73

Consider the following equilibrium: 2H₂(g)+ X₂(g) 2H₂X(g)+ energy
Addition of X₂ to a system described by the above equilibrium

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

Question 74

Consider the following equilibrium: 2H₂(g)+ X₂(g) 2H₂X(g)+ energy
Addition of argon to the above 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 75

Exactly 1.0 mol N₂O₄ is placed in an empty 1.0-L container and is allowed to reach equilibrium described by the equation N₂O₄(g) 2NO₂(g) If at equilibrium the N₂O₄ is 37% dissociated,what is the value of the equilibrium constant,K_c,for the reaction under these conditions?

A)1.2
B)0.87
C)1.20
D)0.55
E)0.22

Question 76

The following questions refer to the equilibrium shown here: 4NH₃(g)+ 5O₂(g) 4NO(g)+ 6H₂O(g)
What would happen to the system if the pressure were decreased?

A)Nothing would happen.
B)More oxygen would be produced.
C)The water vapor would become liquid water.
D)The ammonia concentration would increase.
E)The NO concentration would increase.

Question 77

Increasing the pressure by decreasing the volume will cause

A)the reaction to occur to produce H₂X
B)the reaction to occur to produce H₂ and X₂
C)the reaction to occur to produce H₂ but no more X₂
D)no reaction to occur
E)X₂ to dissociate

Question 78

The questions below refer to the following system:
Co(H₂O)₆²⁺ + 4 Cl^- CoCl₄^2- + 6H₂O
(pink)
(blue)
When cobalt(II)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.
Which statement below describes the change that the system will undergo if hydrochloric acid is added?

A)It should become more blue.
B)It should become more pink.
C)The equilibrium will shift to the right.
D)The equilibrium will shift to the left.
E)Two of these.

Question 79

At -80°C,K for the reaction N₂O₄(g) 2NO₂(g)
Is 4.66 $\times$ 10^-8.We introduce 0.047 mole of N₂O₄ into a 1.0-L vessel at -80°C and let equilibrium be established.The total pressure in the system at equilibrium will be:

A)0.31 atm
B)0.74 atm
C)1.4 atm
D)0.047 atm
E)none of these

Question 80

The questions below refer to the following system:
Co(H₂O)₆²⁺ + 4 Cl^- CoCl₄^2- + 6H₂O
(pink)
(blue)
When cobalt(II)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.
Which statement below describes the change that the system will undergo if silver nitrate is added?

A)It should become more blue.
B)It should become more pink.
C)Water will be produced.
D)The silver ion will react with the CoCl₄^2-.
E)Nothing will change.