Question 1

Calculate Kp for the reaction 2NOCl(g)      2NO(g)+ Cl2(g)at 400°C if Kc at 400°C for this reaction is 2.1 * 10-2.

Accepted Answer

A) 2.1 * 10-2 
B) 1.7 * 10-3 
C) 0.70 
D) 1.2 
E) 3.8 * 10-4 
A) 2.1 * 10-2 
B) 1.7 * 10-3 
C) 0.70 
D) 1.2 
E) 3.8 * 10-4 D

Question 2

If the reaction 2H2S(g)      2H2(g)+ S2(g)is carried out at 1065°C, Kp = 0.0120. Starting from pure H2S introduced into an evacuated vessel at 1065°C, what will the total pressure in the vessel be at equilibrium if the equilibrated mixture contains 0.300 atm of H2(g)?

Accepted Answer

A) 1.06 atm 
B) 1.36 atm 
C) 2.39 atm 
D) 4.20 atm 
E) 1.51 atm 
A) 1.06 atm 
B) 1.36 atm 
C) 2.39 atm 
D) 4.20 atm 
E) 1.51 atm E

Question 3

Hydrogen iodide decomposes according to the equation 2HI(g)     H2(g)+ I2(g), for which Kc = 0.0156 at 400ºC. 0.550 mol HI was injected into a 2.00 L reaction vessel at 400ºC.Calculate the concentration of HI at equilibrium.

Accepted Answer

A) 0.138 M 
B) 0.220 M 
C) 0.550 M 
D) 0.275 M 
E) 0.0275 M 
A) 0.138 M 
B) 0.220 M 
C) 0.550 M 
D) 0.275 M 
E) 0.0275 M B

Question 4

Consider the equilibrium equation C(s)+ H2O(g)+ 2296 J    
CO(g)+ H2(g).What will happen to the concentration of carbon monoxide if the temperature of this system is raised?

Accepted Answer

Question 5

Equilibrium constants are known for the following reactions:
S(s)+ 3/2O2(g)    
SO3(g)Kc = 9.2 * 1023
 SO3(g)    
SO2(g)+ 1/2O2(g)Kc = 4.8 *10- 4
 Thus, for the reaction S(s)+ O2(g)    
SO2(g), Kc = 4.4 * 1020.

Accepted Answer

A) True 
 B)False

Question 6

Consider the following equilibrium,
4NH3(g)+ 3O2(g)    
2N2(g)+ 6H2O(g)+ 1531 kJ
State whether the concentrations of the reactants would increase, decrease, or remain constant when the temperature is increased.

Accepted Answer

Question 7

For the reaction at equilibrium 2SO3     2SO2 + O2 ($\Delta$Hºrxn= 198 kJ/mol), if we increase the reaction temperature, the equilibrium will

Accepted Answer

A) shift to the right. 
B) shift to the left. 
C) not shift. 
D) The question cannot be answered because the equilibrium constant is not given. 
A) shift to the right. 
B) shift to the left. 
C) not shift. 
D) The question cannot be answered because the equilibrium constant is not given.

Question 8

Consider this gas phase equilibrium system: PCl5(g)    
PCl3(g)+ Cl2(g)$\Delta$Hºrxn = +87.8 kJ/mol.
Which of these statements is false?

Accepted Answer

A) Increasing the system volume shifts the equilibrium to the right. 
B) Increasing the temperature shifts the equilibrium to the right. 
C) A catalyst speeds up the approach to equilibrium and shifts the position of equilibrium to the right. 
D) Decreasing the total pressure of the system shifts the equilibrium to the right. 
E) Increasing the temperature causes the equilibrium constant to increase. 
A) Increasing the system volume shifts the equilibrium to the right. 
B) Increasing the temperature shifts the equilibrium to the right. 
C) A catalyst speeds up the approach to equilibrium and shifts the position of equilibrium to the right. 
D) Decreasing the total pressure of the system shifts the equilibrium to the right. 
E) Increasing the temperature causes the equilibrium constant to increase.

Question 9

Kp for the reaction of SO2(g)with O2 to produce SO3(g)is 3 * 1024 .Calculate Kc for this equilibrium at 25ºC. (The relevant reaction is 2SO2(g)+ O2(g)      2SO3(g).)

Accepted Answer

A) 3 * 1024 
B) 5 * 1021 
C) 2 * 1020 
D) 5 * 1022 
E) 7 * 1025 
A) 3 * 1024 
B) 5 * 1021 
C) 2 * 1020 
D) 5 * 1022 
E) 7 * 1025

Question 10

For the common allotropes of carbon (graphite and diamond), C(gr)    C(dia)with equilibrium constant K = 0.32. The molar volumes of graphite and diamond are, respectively, 5.30 cm3/mol and 3.42 cm3/mol; $\Delta$Hf of diamond is 1.90 kJ/mol. This data suggests that the formation of diamond is favored at

Accepted Answer

A) low temperatures and low pressures. 
B) high temperatures and low pressures. 
C) low temperatures and high pressures. 
D) high temperatures and high pressures. 
A) low temperatures and low pressures. 
B) high temperatures and low pressures. 
C) low temperatures and high pressures. 
D) high temperatures and high pressures.

Question 11

For the following reaction at equilibrium, which one of the changes below would cause the equilibrium to shift to the left? 2NOBr(g)    
2NO(g)+ Br2(g), $\Delta$Hºrxn = 30 kJ/mol

Accepted Answer

A) Increase the container volume. 
B) Remove some NO. 
C) Remove some Br2 . 
D) Add more NOBr. 
E) Decrease the temperature. 
A) Increase the container volume. 
B) Remove some NO. 
C) Remove some Br2 . 
D) Add more NOBr. 
E) Decrease the temperature.

Question 12

The reaction 2SO3(g)     2SO2(g)+ O2(g)is endothermic. If the temperature is increased,

Accepted Answer

A) more SO3 will be produced. 
B) Kc will decrease. 
C) no change will occur in Kc . 
D) Kc will increase. 
E) the pressure will decrease. 
A) more SO3 will be produced. 
B) Kc will decrease. 
C) no change will occur in Kc . 
D) Kc will increase. 
E) the pressure will decrease.

Question 13

At 400ºC, Kc = 64 for the equilibrium H2(g)+ I2(g)     2HI(g). If 3.00 mol H2 and 3.00 mol I2 are introduced into an empty 4.0 L vessel, find the equilibrium concentration of HI at 400ºC.

Accepted Answer

A) 0.15 M 
B) 1.2 M 
C) 2.4 M 
D) 4.8 M 
E) 5.8 M 
A) 0.15 M 
B) 1.2 M 
C) 2.4 M 
D) 4.8 M 
E) 5.8 M

Question 14

For the equilibrium reaction 2SO2(g)+ O2(g)     2SO3(g), $\Delta$Hºrxn = -198 kJ/mol. Which one of these factors would cause the equilibrium constant to increase?

Accepted Answer

A) Decrease the temperature. 
B) Add SO2 gas. 
C) Remove O2 gas. 
D) Add a catalyst. 
E) None of these. 
A) Decrease the temperature. 
B) Add SO2 gas. 
C) Remove O2 gas. 
D) Add a catalyst. 
E) None of these.

Question 15

For the nitrogen fixation reaction 3H2(g)+ N2(g)     2NH3(g), Kc = 6.0 * 10-2 at 500°C. If 0.250 M H2 and 0.050 M NH3 are present at equilibrium, what is the equilibrium concentration of N2?

Accepted Answer

A) 0.750 M 
B) 2.7 M 
C) 0.250 M 
D) 0.025 M 
E) 1.85 M 
A) 0.750 M 
B) 2.7 M 
C) 0.250 M 
D) 0.025 M 
E) 1.85 M

Question 16

Kc for the reaction CO2(g)+ H2(g)    
H2O(g)+ CO(g)is 1.6 at about 990ºC.Calculate the number of moles of hydrogen gas in the final equilibrium system obtained by initially adding 1.00 mol of H2, 2.00 mol of CO2, 0.750 mol of H2O, and 1.00 mol of CO to a 5.00 L reactor at 990ºC.

Accepted Answer

Question 17

When the following reaction is at equilibrium, which of these relationships is always true? 2NOCl(g)    
2NO(g)+ Cl2(g)

Accepted Answer

A) [NO] [Cl2] = [NOCl] 
B) [NO]2 [Cl2] = [NOCl]2 
C) [NOCl] = [NO] 
D) 2[NO] = [Cl2] 
E) [NO]2 [Cl2] = Kc[NOCl]2 
A) [NO] [Cl2] = [NOCl] 
B) [NO]2 [Cl2] = [NOCl]2 
C) [NOCl] = [NO] 
D) 2[NO] = [Cl2] 
E) [NO]2 [Cl2] = Kc[NOCl]2

Question 18

Consider the following equilibrium,
4NH3(g)+ 3O2(g)    
2N2(g)+ 6H2O(g)+ 1531 kJ
State whether the concentrations the products would increase, decrease, or remain constant after nitrogen gas was removed from the system.

Accepted Answer

Question 19

Consider the reaction N2(g)+ 3H2(g)    
2NH3(g). If we use a catalyst, which way will the reaction shift?

Accepted Answer

Addition of a cataly

Question 20

For the following reaction at equilibrium, which choice gives a change that will shift the position of equilibrium to favor formation of more products? 2NOBr(g)    
2NO(g)+ Br2(g), $\Delta$Hºrxn = 30 kJ/mol

Accepted Answer

A) Increase the total pressure by decreasing the volume. 
B) Add more NO. 
C) Remove Br2. 
D) Lower the temperature. 
E) Remove NOBr selectively. 
A) Increase the total pressure by decreasing the volume. 
B) Add more NO. 
C) Remove Br2. 
D) Lower the temperature. 
E) Remove NOBr selectively.

Calculate K_p for the reaction 2NOCl(g) 2NO(g)+ Cl₂(g)at 400°C if K_c at 400°C for this reaction is 2.1 * 10^-2.

If the reaction 2H₂S(g) 2H₂(g)+ S₂(g)is carried out at 1065°C, K_p = 0.0120. Starting from pure H₂S introduced into an evacuated vessel at 1065°C, what will the total pressure in the vessel be at equilibrium if the equilibrated mixture contains 0.300 atm of H₂(g)?

Hydrogen iodide decomposes according to the equation 2HI(g) H₂(g)+ I₂(g), for which K_c = 0.0156 at 400ºC. 0.550 mol HI was injected into a 2.00 L reaction vessel at 400ºC.Calculate the concentration of HI at equilibrium.

Consider the equilibrium equation C(s)+ H₂O(g)+ 2296 J CO(g)+ H₂(g).What will happen to the concentration of carbon monoxide if the temperature of this system is raised?

Equilibrium constants are known for the following reactions: S(s)+ ³/₂O₂(g) SO₃(g)K_c = 9.2 * 10²³ SO₃(g) SO₂(g)+ ¹/₂O₂(g)K_c = 4.8 10^{- 4} Thus, for the reaction S(s)+ O₂(g) SO₂(g), K_c = 4.4 10²⁰.

Consider the following equilibrium, 4NH₃(g)+ 3O₂(g) 2N₂(g)+ 6H₂O(g)+ 1531 kJ State whether the concentrations of the reactants would increase, decrease, or remain constant when the temperature is increased.

K_p for the reaction of SO₂(g)with O₂ to produce SO₃(g)is 3 * 10²⁴ .Calculate K_c for this equilibrium at 25ºC. (The relevant reaction is 2SO₂(g)+ O₂(g) 2SO₃(g).)

The reaction 2SO₃(g) 2SO₂(g)+ O₂(g)is endothermic. If the temperature is increased,

At 400ºC, K_c = 64 for the equilibrium H₂(g)+ I₂(g) 2HI(g). If 3.00 mol H₂ and 3.00 mol I₂ are introduced into an empty 4.0 L vessel, find the equilibrium concentration of HI at 400ºC.

For the nitrogen fixation reaction 3H₂(g)+ N₂(g) 2NH₃(g), K_c = 6.0 * 10^-2 at 500°C. If 0.250 M H₂ and 0.050 M NH₃ are present at equilibrium, what is the equilibrium concentration of N₂?

K_c for the reaction CO₂(g)+ H₂(g) H₂O(g)+ CO(g)is 1.6 at about 990ºC.Calculate the number of moles of hydrogen gas in the final equilibrium system obtained by initially adding 1.00 mol of H₂, 2.00 mol of CO₂, 0.750 mol of H₂O, and 1.00 mol of CO to a 5.00 L reactor at 990ºC.

When the following reaction is at equilibrium, which of these relationships is always true? 2NOCl(g) 2NO(g)+ Cl₂(g)

Consider the following equilibrium, 4NH₃(g)+ 3O₂(g) 2N₂(g)+ 6H₂O(g)+ 1531 kJ State whether the concentrations the products would increase, decrease, or remain constant after nitrogen gas was removed from the system.

Consider the reaction N₂(g)+ 3H₂(g) 2NH₃(g). If we use a catalyst, which way will the reaction shift?

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Exam 14: Chemical Equilibrium

Calculate Kp for the reaction 2NOCl(g) 2NO(g)+ Cl2(g)at 400°C if Kc at 400°C for this reaction is 2.1 * 10-2.

If the reaction 2H2S(g) 2H2(g)+ S2(g)is carried out at 1065°C, Kp = 0.0120. Starting from pure H2S introduced into an evacuated vessel at 1065°C, what will the total pressure in the vessel be at equilibrium if the equilibrated mixture contains 0.300 atm of H2(g)?

Hydrogen iodide decomposes according to the equation 2HI(g) H2(g)+ I2(g), for which Kc = 0.0156 at 400ºC. 0.550 mol HI was injected into a 2.00 L reaction vessel at 400ºC.Calculate the concentration of HI at equilibrium.

Consider the equilibrium equation C(s)+ H2O(g)+ 2296 J CO(g)+ H2(g).What will happen to the concentration of carbon monoxide if the temperature of this system is raised?

Equilibrium constants are known for the following reactions: S(s)+ 3/2O2(g) SO3(g)Kc = 9.2 * 1023 SO3(g) SO2(g)+ 1/2O2(g)Kc = 4.8 *10- 4 Thus, for the reaction S(s)+ O2(g) SO2(g), Kc = 4.4 * 1020.

Consider the following equilibrium, 4NH3(g)+ 3O2(g) 2N2(g)+ 6H2O(g)+ 1531 kJ State whether the concentrations of the reactants would increase, decrease, or remain constant when the temperature is increased.

For the reaction at equilibrium 2SO3 2SO2 + O2 ( Δ\DeltaΔ Hºrxn= 198 kJ/mol), if we increase the reaction temperature, the equilibrium will

Consider this gas phase equilibrium system: PCl5(g) PCl3(g)+ Cl2(g) Δ\DeltaΔ Hºrxn = +87.8 kJ/mol. Which of these statements is false?

Kp for the reaction of SO2(g)with O2 to produce SO3(g)is 3 * 1024 .Calculate Kc for this equilibrium at 25ºC. (The relevant reaction is 2SO2(g)+ O2(g) 2SO3(g).)

For the following reaction at equilibrium, which one of the changes below would cause the equilibrium to shift to the left? 2NOBr(g) 2NO(g)+ Br2(g), Δ\DeltaΔ Hºrxn = 30 kJ/mol

The reaction 2SO3(g) 2SO2(g)+ O2(g)is endothermic. If the temperature is increased,

At 400ºC, Kc = 64 for the equilibrium H2(g)+ I2(g) 2HI(g). If 3.00 mol H2 and 3.00 mol I2 are introduced into an empty 4.0 L vessel, find the equilibrium concentration of HI at 400ºC.

For the equilibrium reaction 2SO2(g)+ O2(g) 2SO3(g), Δ\DeltaΔ Hºrxn = -198 kJ/mol. Which one of these factors would cause the equilibrium constant to increase?

For the nitrogen fixation reaction 3H2(g)+ N2(g) 2NH3(g), Kc = 6.0 * 10-2 at 500°C. If 0.250 M H2 and 0.050 M NH3 are present at equilibrium, what is the equilibrium concentration of N2?

Kc for the reaction CO2(g)+ H2(g) H2O(g)+ CO(g)is 1.6 at about 990ºC.Calculate the number of moles of hydrogen gas in the final equilibrium system obtained by initially adding 1.00 mol of H2, 2.00 mol of CO2, 0.750 mol of H2O, and 1.00 mol of CO to a 5.00 L reactor at 990ºC.

When the following reaction is at equilibrium, which of these relationships is always true? 2NOCl(g) 2NO(g)+ Cl2(g)

Consider the following equilibrium, 4NH3(g)+ 3O2(g) 2N2(g)+ 6H2O(g)+ 1531 kJ State whether the concentrations the products would increase, decrease, or remain constant after nitrogen gas was removed from the system.

Consider the reaction N2(g)+ 3H2(g) 2NH3(g). If we use a catalyst, which way will the reaction shift?

For the following reaction at equilibrium, which choice gives a change that will shift the position of equilibrium to favor formation of more products? 2NOBr(g) 2NO(g)+ Br2(g), Δ\DeltaΔ Hºrxn = 30 kJ/mol