Question 1

What is the equilibrium equation for the following reaction?
2 H2O (l)⇌ H3O+ (aq)+ OH- (aq)

Accepted Answer

A) Kc =   
B) Kc =   
C) Kc =   
D) Kc = [H3O+] [OH-] 
A) Kc =   
B) Kc =   
C) Kc =   
D) Kc = [H3O+] [OH-]

Question 2

Picture (1)represents the equilibrium mixture for the reaction A + B ⇌ 2 AB at 298 K.  
-If this reaction is exothermic,which picture (2)-(4)represents the equilibrium mixture at 400 K?

Accepted Answer

A) picture (2) 
B) picture (3) 
C) picture (4) 
D) None of these 
A) picture (2) 
B) picture (3) 
C) picture (4) 
D) None of these

Question 3

At an elevated temperature,Kp = 0.19 for the reaction 2 NOCl(g)⇌ 2 NO(g)+ Cl2(g).If the initial partial pressures of NOCl,NO,and Cl2 are 0.50 atm,0.25 atm,and 0.45 atm,respectively,a net ________ (forward,reverse)reaction must occur in order to achieve equilibrium.

Accepted Answer

Question 4

At a certain temperature,nitrogen and hydrogen react to form ammonia:
N2(g)+ 3 H2(g)⇌ 2 NH3(g).
When initial amounts of N2,H2,and NH3 are mixed,the concentration of NH3 increases.Which statement below is true?

Accepted Answer

A) Kc c > Q 
C) Kc = Q 
D) More information is needed to make a statement about Kc. 
A) Kc c > Q 
C) Kc = Q 
D) More information is needed to make a statement about Kc.

Question 5

A 1.50 L vessel contains an equilibrium mixture of 0.100 mol of NO,0.150 mol of Br2,and
0)250 mol of NOBr at 25°C.What is the value of Kp for the reaction below?
2 NO(g)+ Br2(g)⇌ 2 NOBr(g)

Accepted Answer

A) 2)56 
B) 62.5 
C) 1)28 × 102 
D) 1)53 × 103 
A) 2)56 
B) 62.5 
C) 1)28 × 102 
D) 1)53 × 103

Question 6

The enthalpy for the following reaction is 136 kJ.If the reaction takes place in a closed container,which one of the following reaction conditions will not decrease the concentration of water vapor?
2 NaHCO3(s)⇌ Na2CO3(s)+ CO2(g)+ H2O(g)

Accepted Answer

A) add CO2 
B) cool the container 
C) decrease the volume of the container 
D) remove some NaHCO3 
A) add CO2 
B) cool the container 
C) decrease the volume of the container 
D) remove some NaHCO3

Question 7

The following pictures represent mixtures of A2B4 molecules and AB2 molecules,which interconvert according to the equation A2B4 ⇌ 2 AB2.If mixture (1)is at equilibrium,which of the other mixtures are also at equilibrium?

Accepted Answer

A) mixture (2) 
B) mixture (3) 
C) mixture (4) 
D) None of the other mixtures are at equilibrium. 
A) mixture (2) 
B) mixture (3) 
C) mixture (4) 
D) None of the other mixtures are at equilibrium.

Question 8

At 1000 K,Kp = 19.9 for the reaction Fe2O3(s)+ 3 CO(g)⇌ 2 Fe(s)+ 3 CO2(g).What is the value of Kp for the reaction 6 Fe(s)+ 9 CO2(g)⇌ 3 Fe2O3(s)+ 9 CO(g)?

Accepted Answer

Question 9

Which one of the following statements does not describe the equilibrium state?

Accepted Answer

A) Equilibrium is dynamic and there is no net conversion to reactants and products. 
B) The concentration of the reactants is equal to the concentration of the products. 
C) The concentration of the reactants and products reach a constant level. 
D) The rate of the forward reaction is equal to the rate of the reverse reaction. 
A) Equilibrium is dynamic and there is no net conversion to reactants and products. 
B) The concentration of the reactants is equal to the concentration of the products. 
C) The concentration of the reactants and products reach a constant level. 
D) The rate of the forward reaction is equal to the rate of the reverse reaction.

Question 10

Consider the interconversion of A molecules (shaded spheres)and B molecules (unshaded spheres)according to the reaction A ⇌ B.Each of the following series of pictures represents a separate experiment in which time increases from left to right.  
-What is the value of the equilibrium constant Kc for the reaction A ⇌ B?

Accepted Answer

A) Kc = 0.33 
B) Kc = 3.0 
C) Kc = 12 
D) Kc = 27 
A) Kc = 0.33 
B) Kc = 3.0 
C) Kc = 12 
D) Kc = 27

Question 11

For the reaction: N2(g)+ 2 O2(g)⇌ 2 NO2(g),Kc = 8.3 × 10-10 at 25°C.What is the concentration of N2 gas at equilibrium when the concentration of NO2 is twice the concentration of O2 gas?

Accepted Answer

A) 2)1 × 10-10 M 
B) 4)2 × 10-10 M 
C) 2)4 × 109 M 
D) 4)8 × 109 M 
A) 2)1 × 10-10 M 
B) 4)2 × 10-10 M 
C) 2)4 × 109 M 
D) 4)8 × 109 M

Question 12

For the reaction shown below,which change in conditions made to the system at equilibrium will result in a net reaction to the right to form more product?
C(s)+ 2 H2(g)⇌ CH4(g)ΔH° = - 74.8 kJ

Accepted Answer

A) adding He 
B) adding more C 
C) decreasing the volume 
D) increasing the volume 
A) adding He 
B) adding more C 
C) decreasing the volume 
D) increasing the volume

Question 13

Which change in the system will drive equilibrium to the left in the reaction below?
N2O5(g)⇌ NO2(g)+ NO3(g)

Accepted Answer

A) decrease the amount of NO3 
B) increase the amount of N2O5 
C) increase the pressure 
D) increase the volume 
A) decrease the amount of NO3 
B) increase the amount of N2O5 
C) increase the pressure 
D) increase the volume

Question 14

The equilibrium constant,Kp,equals 3.40 for the isomerization reaction:
Cis-2-butene ⇌ trans-2-butene.
If a flask initially contains 0.250 atm of cis-2-butene and 0.125 atm of trans-2-butene,what is the equilibrium pressure of each gas?

Accepted Answer

A) P(cis-2-butene)= 0.037 atm,P(trans-2-butene)= 0.125 atm 
B) P(cis-2-butene)= 0.048 atm,P(trans-2-butene)= 0.165 atm 
C) P(cis-2-butene)= 0.074 atm,P(trans-2-butene)= 0.250 atm 
D) P(cis-2-butene)= 0.085 atm,P(trans-2-butene)= 0.290 atm 
A) P(cis-2-butene)= 0.037 atm,P(trans-2-butene)= 0.125 atm 
B) P(cis-2-butene)= 0.048 atm,P(trans-2-butene)= 0.165 atm 
C) P(cis-2-butene)= 0.074 atm,P(trans-2-butene)= 0.250 atm 
D) P(cis-2-butene)= 0.085 atm,P(trans-2-butene)= 0.290 atm

Question 15

The equilibrium constant,Kp,equals 3.40 at 25°C for the isomerization reaction:
Cis-2-butene ⇌ trans-2-butene.
If a flask initially contains 1.00 atm of each gas,in what direction will the system shift to reach equilibrium?

Accepted Answer

A) It will shift left. 
B) It will shift right. 
C) The system is already at equilibrium. 
D) The system is not at equilibrium and will remain in an unequilibrated state. 
A) It will shift left. 
B) It will shift right. 
C) The system is already at equilibrium. 
D) The system is not at equilibrium and will remain in an unequilibrated state.

Question 16

At a certain temperature,bromine and nitric oxide react to form nitrosyl bromide:
Br2(g)+ 2 NO(g)⇌ 2 NOBr(g).
When initial amounts of Br2,NO,and NOBr are mixed,the concentration of NOBr increases.Which statement below is true?

Accepted Answer

A) Kc c > Q 
C) Kc = Q 
D) More information is needed to make a statement about Kc. 
A) Kc c > Q 
C) Kc = Q 
D) More information is needed to make a statement about Kc.

Question 17

The equilibrium equation is also known as the law of

Accepted Answer

A) coefficients. 
B) constant concentration. 
C) dynamic equilibrium. 
D) mass action. 
A) coefficients. 
B) constant concentration. 
C) dynamic equilibrium. 
D) mass action.

Question 18

The following pictures represent mixtures of A2B4 molecules and AB2 molecules,which interconvert according to the equation A2B4 ⇌ 2 AB2.If mixture (1)is at equilibrium,which of the other mixtures are also at equilibrium?

Accepted Answer

A) mixture (2) 
B) mixture (3) 
C) mixture (4) 
D) None of the other mixtures are at equilibrium. 
A) mixture (2) 
B) mixture (3) 
C) mixture (4) 
D) None of the other mixtures are at equilibrium.

Question 19

As a rule,which of the following phases are not included in the equilibrium constant expression?
I.pure liquids
 II.pure solids
 III.aqueous solutions
 IV.gases

Accepted Answer

A) I,II 
B) I,IV 
C) III,IV 
D) II,III 
A) I,II 
B) I,IV 
C) III,IV 
D) II,III

Question 20

Cyclohexane (C6H12)undergoes a molecular rearrangement in the presence of AlCl3 to form methylcyclopentane (MCP)according to the equation:
C6H12 ⇌ MCP
If Kc = 0.143 at 25°C for this reaction,predict the direction in which the system will shift if the initial concentrations of C6H12 and MCP are 0.0400 M and 0.0200 M,respectively.The system

Accepted Answer

A) will shift left. 
B) will shift right. 
C) is already at equilibrium. 
D) is not at equilibrium and will remain in an unequilibrated state. 
A) will shift left. 
B) will shift right. 
C) is already at equilibrium. 
D) is not at equilibrium and will remain in an unequilibrated state.

Exam 13: Chemical Equilibrium

What is the equilibrium equation for the following reaction? 2 H2O (l)⇌ H3O+ (aq)+ OH- (aq)

Picture (1)represents the equilibrium mixture for the reaction A + B ⇌ 2 AB at 298 K. -If this reaction is exothermic,which picture (2)-(4)represents the equilibrium mixture at 400 K?

At an elevated temperature,Kp = 0.19 for the reaction 2 NOCl(g)⇌ 2 NO(g)+ Cl2(g).If the initial partial pressures of NOCl,NO,and Cl2 are 0.50 atm,0.25 atm,and 0.45 atm,respectively,a net ________ (forward,reverse)reaction must occur in order to achieve equilibrium.

At a certain temperature,nitrogen and hydrogen react to form ammonia: N2(g)+ 3 H2(g)⇌ 2 NH3(g). When initial amounts of N2,H2,and NH3 are mixed,the concentration of NH3 increases.Which statement below is true?

A 1.50 L vessel contains an equilibrium mixture of 0.100 mol of NO,0.150 mol of Br2,and 0)250 mol of NOBr at 25°C.What is the value of Kp for the reaction below? 2 NO(g)+ Br2(g)⇌ 2 NOBr(g)

The enthalpy for the following reaction is 136 kJ.If the reaction takes place in a closed container,which one of the following reaction conditions will not decrease the concentration of water vapor? 2 NaHCO3(s)⇌ Na2CO3(s)+ CO2(g)+ H2O(g)

The following pictures represent mixtures of A2B4 molecules and AB2 molecules,which interconvert according to the equation A2B4 ⇌ 2 AB2.If mixture (1)is at equilibrium,which of the other mixtures are also at equilibrium?

At 1000 K,Kp = 19.9 for the reaction Fe2O3(s)+ 3 CO(g)⇌ 2 Fe(s)+ 3 CO2(g).What is the value of Kp for the reaction 6 Fe(s)+ 9 CO2(g)⇌ 3 Fe2O3(s)+ 9 CO(g)?

Which one of the following statements does not describe the equilibrium state?

For the reaction: N2(g)+ 2 O2(g)⇌ 2 NO2(g),Kc = 8.3 × 10-10 at 25°C.What is the concentration of N2 gas at equilibrium when the concentration of NO2 is twice the concentration of O2 gas?

For the reaction shown below,which change in conditions made to the system at equilibrium will result in a net reaction to the right to form more product? C(s)+ 2 H2(g)⇌ CH4(g)ΔH° = - 74.8 kJ

Which change in the system will drive equilibrium to the left in the reaction below? N2O5(g)⇌ NO2(g)+ NO3(g)

The equilibrium constant,Kp,equals 3.40 for the isomerization reaction: Cis-2-butene ⇌ trans-2-butene. If a flask initially contains 0.250 atm of cis-2-butene and 0.125 atm of trans-2-butene,what is the equilibrium pressure of each gas?

The equilibrium constant,Kp,equals 3.40 at 25°C for the isomerization reaction: Cis-2-butene ⇌ trans-2-butene. If a flask initially contains 1.00 atm of each gas,in what direction will the system shift to reach equilibrium?

At a certain temperature,bromine and nitric oxide react to form nitrosyl bromide: Br2(g)+ 2 NO(g)⇌ 2 NOBr(g). When initial amounts of Br2,NO,and NOBr are mixed,the concentration of NOBr increases.Which statement below is true?

The equilibrium equation is also known as the law of

The following pictures represent mixtures of A2B4 molecules and AB2 molecules,which interconvert according to the equation A2B4 ⇌ 2 AB2.If mixture (1)is at equilibrium,which of the other mixtures are also at equilibrium?

As a rule,which of the following phases are not included in the equilibrium constant expression? I.pure liquids II.pure solids III.aqueous solutions IV.gases

Chemistry: Matter and Measurement

Atoms, molecules, and Ions

Formulas, equations, and Moles

Reactions in Aqueous Solutions

Periodicity and the Atomic Structure of Atoms

Ionic Bonds and Some Main-Group Chemistry

Covalent Bonds and Molecular Structure

Thermochemistry: Chemical Energy

Gases: Their Properties and Behavior

Liquids,solids,and Phase Changes

Solutions and Their Properties

Chemical Kinetics

Aqueous Equilibria: Acids and Bases

Applications of Aqueous Equilibria

Thermodynamics: Entropy, free Energy, and Equilibrium

Electrochemistry

Hydrogen, oxygen, and Water

The Main-Group Elements

Transition Elements and Coordination Chemistry

Metals and Solid-State Materials

Nuclear Chemistry

Organic and Biological Chemistry

Filters

What is the equilibrium equation for the following reaction? 2 H₂O (l)⇌ H₃O⁺ (aq)+ OH^- (aq)

At an elevated temperature,K_p = 0.19 for the reaction 2 NOCl(g)⇌ 2 NO(g)+ Cl₂(g).If the initial partial pressures of NOCl,NO,and Cl₂ are 0.50 atm,0.25 atm,and 0.45 atm,respectively,a net ________ (forward,reverse)reaction must occur in order to achieve equilibrium.

At a certain temperature,nitrogen and hydrogen react to form ammonia: N₂(g)+ 3 H₂(g)⇌ 2 NH₃(g). When initial amounts of N₂,H₂,and NH₃ are mixed,the concentration of NH₃ increases.Which statement below is true?

A 1.50 L vessel contains an equilibrium mixture of 0.100 mol of NO,0.150 mol of Br₂,and 0)250 mol of NOBr at 25°C.What is the value of K_p for the reaction below? 2 NO(g)+ Br₂(g)⇌ 2 NOBr(g)

The enthalpy for the following reaction is 136 kJ.If the reaction takes place in a closed container,which one of the following reaction conditions will not decrease the concentration of water vapor? 2 NaHCO₃(s)⇌ Na₂CO₃(s)+ CO₂(g)+ H₂O(g)

The following pictures represent mixtures of A₂B₄ molecules and AB₂ molecules,which interconvert according to the equation A₂B₄ ⇌ 2 AB₂.If mixture (1)is at equilibrium,which of the other mixtures are also at equilibrium?

At 1000 K,K_p = 19.9 for the reaction Fe₂O₃(s)+ 3 CO(g)⇌ 2 Fe(s)+ 3 CO₂(g).What is the value of K_p for the reaction 6 Fe(s)+ 9 CO₂(g)⇌ 3 Fe₂O₃(s)+ 9 CO(g)?

For the reaction: N₂(g)+ 2 O₂(g)⇌ 2 NO₂(g),K_c = 8.3 × 10^-10 at 25°C.What is the concentration of N₂ gas at equilibrium when the concentration of NO₂ is twice the concentration of O₂ gas?

For the reaction shown below,which change in conditions made to the system at equilibrium will result in a net reaction to the right to form more product? C(s)+ 2 H₂(g)⇌ CH₄(g)ΔH° = - 74.8 kJ

Which change in the system will drive equilibrium to the left in the reaction below? N₂O₅(g)⇌ NO₂(g)+ NO₃(g)

The equilibrium constant,K_p,equals 3.40 for the isomerization reaction: Cis-2-butene ⇌ trans-2-butene. If a flask initially contains 0.250 atm of cis-2-butene and 0.125 atm of trans-2-butene,what is the equilibrium pressure of each gas?

The equilibrium constant,K_p,equals 3.40 at 25°C for the isomerization reaction: Cis-2-butene ⇌ trans-2-butene. If a flask initially contains 1.00 atm of each gas,in what direction will the system shift to reach equilibrium?

At a certain temperature,bromine and nitric oxide react to form nitrosyl bromide: Br₂(g)+ 2 NO(g)⇌ 2 NOBr(g). When initial amounts of Br₂,NO,and NOBr are mixed,the concentration of NOBr increases.Which statement below is true?

The following pictures represent mixtures of A₂B₄ molecules and AB₂ molecules,which interconvert according to the equation A₂B₄ ⇌ 2 AB₂.If mixture (1)is at equilibrium,which of the other mixtures are also at equilibrium?