Question 1

Phosgene, COCl2, a poisonous gas, decomposes according to the equation COCl2(g)    CO(g)+ Cl2(g). Calculate Kp for this reaction if Kc = 0.083 at 900ºC.

Accepted Answer

A) 0.125 
B) 8.0 
C) 6.1 
D) 0.16 
E) 0.083 
A) 0.125 
B) 8.0 
C) 6.1 
D) 0.16 
E) 0.083

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

Question 3

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)$\rarr$ SO2(g), Kc = 4.4 * 1020.

Accepted Answer

A) True 
 B)False

Question 4

Equilibrium is established for the reaction 2X(s)+ Y(g)$\rarr$ 2Z(g)at 500K, Kc = 100. Determine the concentration of Z in equilibrium with 0.2 mol X and 0.50 M Y at 500K.

Accepted Answer

A) 3.2 M 
B) 3.5 M 
C) 4.5 M 
D) 7.1 M 
E) None of these. 
A) 3.2 M 
B) 3.5 M 
C) 4.5 M 
D) 7.1 M 
E) None of these.

Question 5

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

Accepted Answer

Question 6

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 7

Consider this reaction at equilibrium: 2SO2(g)+ O2(g)   2SO3(g), $\Delta$Hºrxn = -198 kJ/mol
If the volume of the system is compressed at constant temperature, what change will occur in the position of the equilibrium?

Accepted Answer

A) A shift to produce more SO2 
B) A shift to produce more O2 
C) No change 
D) A shift to produce more SO3 
A) A shift to produce more SO2 
B) A shift to produce more O2 
C) No change 
D) A shift to produce more SO3

Question 8

The brown gas NO2 and the colorless gas N2O4 exist in equilibrium, 2NO2    N2O4. In an experiment, 0.625 mole of N2O4 was introduced into a 5.00 L vessel and was allowed to decompose until equilibrium was reached. The concentration of N2O4 at equilibrium was 0.0750 M. Calculate Kc for the reaction.

Accepted Answer

A) 7.5 
B) 0.125 
C) 0.0750 
D) 0.10 
E) 0.050 
A) 7.5 
B) 0.125 
C) 0.0750 
D) 0.10 
E) 0.050

Question 9

For the reaction 2NOCl(g)   2NO(g)+ Cl2(g), Kc = 8.0 at a certain temperature. What concentration of NOCl must be put into an empty 4.00 L reaction vessel in order that the equilibrium concentration of NOCl be 1.00 M?

Accepted Answer

A) 1.26 M 
B) 2.25 M 
C) 2.50 M 
D) 3.52 M 
E) 11.0 M 
A) 1.26 M 
B) 2.25 M 
C) 2.50 M 
D) 3.52 M 
E) 11.0 M

Question 10

Calculate Kc for the reaction 2HI(g)       H2(g)+ I2(g)given that the concentrations of each species at equilibrium are as follows: [HI] = 0.85 mol/L, [I2] = 0.60 mol/L, [H2] = 0.27 mol/L.

Accepted Answer

A) 5.25 
B) 0.22 
C) 4.5 
D) 0.19 
E) 1.6 * 102 
A) 5.25 
B) 0.22 
C) 4.5 
D) 0.19 
E) 1.6 * 102

Question 11

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

Question 12

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 13

The equilibrium constant for the reaction Ni(s)+ 4CO(g)$\rarr$ Ni(CO)4(g)is 5.0 * 104 at 25ºC. What is the equilibrium constant for the reaction Ni(CO)4(g)    Ni(s)+ 4CO(g)?

Accepted Answer

A) 2.0 * 10-5 
B) 2.5 * 109 
C) 5.0 * 104 
D) 5.0 * 10-4 
E) 2.0 * 10-3 
A) 2.0 * 10-5 
B) 2.5 * 109 
C) 5.0 * 104 
D) 5.0 * 10-4 
E) 2.0 * 10-3

Question 14

The dissociation of solid silver chloride in water to produce silver ions and chloride ions has an equilibrium constant of 1.8 *  10-18. Based on the magnitude of the equilibrium constant, is silver chloride very soluble in water? Why?

Accepted Answer

K_c here will be [Ag⁺

Question 15

For the following reaction at equilibrium in a reaction vessel, which one of these changes would cause the Br2 concentration to decrease? 2NOBr(g)   2NO(g)+ Br2(g), $\Delta$Hºrxn= 30 kJ/mol

Accepted Answer

A) Increase the temperature. 
B) Remove some NO. 
C) Add more NOBr. 
D) Compress the gas mixture into a smaller volume. 
A) Increase the temperature. 
B) Remove some NO. 
C) Add more NOBr. 
D) Compress the gas mixture into a smaller volume.

Question 16

For the reaction PCl3(g)+ Cl2(g)   PCl5(g)at a particular temperature, Kc = 24.3. Suppose a system at that temperature is prepared with [PCl3] = 0.10 M, [Cl2] = 0.15 M, and [PCl5] = 0.60 M. Which of these statements is true?

Accepted Answer

A) The reaction is at equilibrium. 
B) The reaction will proceed in the direction of forming more PCl5 until equilibrium is reached. 
C) The reaction will proceed in the direction of forming more PCl3 and Cl2 until equilibrium is reached. 
D) None of the above statements is true. 
A) The reaction is at equilibrium. 
B) The reaction will proceed in the direction of forming more PCl5 until equilibrium is reached. 
C) The reaction will proceed in the direction of forming more PCl3 and Cl2 until equilibrium is reached. 
D) None of the above statements is true.

Question 17

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

Question 18

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 19

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

Accepted Answer

Question 20

A quantity of liquid methanol, CH3OH, is introduced into a rigid 3.00-L vessel, the vessel is sealed, and the temperature is raised to 500K. At this temperature, the methanol vaporizes and decomposes according to the reaction CH3OH(g)    CO(g)+ 2 H2(g), Kc= 6.90 * 10-2.
If the concentration of H2 in the equilibrium mixture is 0.426M, what mass of methanol was initially introduced into the vessel?

Accepted Answer

A) 147 g 
B) 74.3 g 
C) 33.9 g 
D) 49.0 g 
E) 24.8 g 
A) 147 g 
B) 74.3 g 
C) 33.9 g 
D) 49.0 g 
E) 24.8 g

Phosgene, COCl₂, a poisonous gas, decomposes according to the equation COCl₂(g) CO(g)+ Cl₂(g). Calculate K_p for this reaction if K_c = 0.083 at 900ºC.

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)?

Equilibrium is established for the reaction 2X(s)+ Y(g) $\rarr$ 2Z(g)at 500K, K_c = 100. Determine the concentration of Z in equilibrium with 0.2 mol X and 0.50 M Y at 500K.

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

For the reaction 2NOCl(g) 2NO(g)+ Cl₂(g), K_c = 8.0 at a certain temperature. What concentration of NOCl must be put into an empty 4.00 L reaction vessel in order that the equilibrium concentration of NOCl be 1.00 M?

Calculate K_c for the reaction 2HI(g) H₂(g)+ I₂(g)given that the concentrations of each species at equilibrium are as follows: [HI] = 0.85 mol/L, [I₂] = 0.60 mol/L, [H₂] = 0.27 mol/L.

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.

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?

The dissociation of solid silver chloride in water to produce silver ions and chloride ions has an equilibrium constant of 1.8 * 10^-18. Based on the magnitude of the equilibrium constant, is silver chloride very soluble in water? Why?

For the reaction PCl₃(g)+ Cl₂(g) PCl₅(g)at a particular temperature, K_c = 24.3. Suppose a system at that temperature is prepared with [PCl₃] = 0.10 M, [Cl₂] = 0.15 M, and [PCl₅] = 0.60 M. Which of these statements is true?

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.

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

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

Introduction

Atoms, Molecules, and Ions

Stoichiometry

Reactions in Aqueous Solution

Gases

Energy Relationships in Chemical Reactions

The Electronic Structure of Atoms

The Periodic Table

Chemical Bonding I: the Covalent Bond

Chemical Bonding Ii: Molecular Geometry and Hybridization of Atomic Orbitals

Introduction to Organic Chemistry

Intermolecular Forces and Liquids and Solids

Physical Properties of Solutions

Chemical Kinetics

Acids and Bases

Acid-Base Equilibria and Solubility Equilibria

Thermodynamics

Redox Reactions and Electrochemistry

The Chemistry of Coordination Compounds

Nuclear Chemistry

Organic Polymerssynthetic and Natural

Filters

Exam 15: Chemical Equilibrium

Phosgene, COCl2, a poisonous gas, decomposes according to the equation COCl2(g) CO(g)+ Cl2(g). Calculate Kp for this reaction if Kc = 0.083 at 900ºC.

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)?

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) →\rarr→ SO2(g), Kc = 4.4 * 1020.

Equilibrium is established for the reaction 2X(s)+ Y(g) →\rarr→ 2Z(g)at 500K, Kc = 100. Determine the concentration of Z in equilibrium with 0.2 mol X and 0.50 M Y at 500K.

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

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?

Consider this reaction at equilibrium: 2SO2(g)+ O2(g) 2SO3(g), Δ\DeltaΔ Hºrxn = -198 kJ/mol If the volume of the system is compressed at constant temperature, what change will occur in the position of the equilibrium?

The brown gas NO2 and the colorless gas N2O4 exist in equilibrium, 2NO2 N2O4. In an experiment, 0.625 mole of N2O4 was introduced into a 5.00 L vessel and was allowed to decompose until equilibrium was reached. The concentration of N2O4 at equilibrium was 0.0750 M. Calculate Kc for the reaction.

For the reaction 2NOCl(g) 2NO(g)+ Cl2(g), Kc = 8.0 at a certain temperature. What concentration of NOCl must be put into an empty 4.00 L reaction vessel in order that the equilibrium concentration of NOCl be 1.00 M?

Calculate Kc for the reaction 2HI(g) H2(g)+ I2(g)given that the concentrations of each species at equilibrium are as follows: [HI] = 0.85 mol/L, [I2] = 0.60 mol/L, [H2] = 0.27 mol/L.

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.

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?

The equilibrium constant for the reaction Ni(s)+ 4CO(g) →\rarr→ Ni(CO)4(g)is 5.0 * 104 at 25ºC. What is the equilibrium constant for the reaction Ni(CO)4(g) Ni(s)+ 4CO(g)?

The dissociation of solid silver chloride in water to produce silver ions and chloride ions has an equilibrium constant of 1.8 * 10-18. Based on the magnitude of the equilibrium constant, is silver chloride very soluble in water? Why?

For the following reaction at equilibrium in a reaction vessel, which one of these changes would cause the Br2 concentration to decrease? 2NOBr(g) 2NO(g)+ Br2(g), Δ\DeltaΔ Hºrxn= 30 kJ/mol

For the reaction PCl3(g)+ Cl2(g) PCl5(g)at a particular temperature, Kc = 24.3. Suppose a system at that temperature is prepared with [PCl3] = 0.10 M, [Cl2] = 0.15 M, and [PCl5] = 0.60 M. Which of these statements is true?

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.

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

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