Question 1

Write the equilibrium constant expression for the reaction:
3 Sn(s)+ 4 HNO3(aq)+ H2O(l)⇌ 3 H2SnO3(s)+ 4 NO(g)

Accepted Answer

A) Kc =   
B) Kc =   
C) Kc =   
D) Kc =   
E) Kc =   
A) Kc =   
B) Kc =   
C) Kc =   
D) Kc =   
E) Kc =   B

Question 2

Consider the following reaction:
POCl3(g)⇌ POCl(g)+ Cl2(g)with Kc = 0.450
A sample of pure POCl3(g)was placed in a reaction vessel and allowed to decompose according to the above reaction.At equilibrium,the concentrations of POCl(g)and Cl2(g)were each 0.150 M.What was the initial concentration of POCl3(g)?

Accepted Answer

A) 0.225 M 
B) 0.200 M 
C) 0.633 M 
D) 0.483 M 
E) 0.350 M 
A) 0.225 M 
B) 0.200 M 
C) 0.633 M 
D) 0.483 M 
E) 0.350 M B

Question 3

Consider the following hypothetical equilibrium reaction:
A2(g)+ B2(g)⇌ 2 AB(g) where Kc =  
The equilibrium constant for the reaction: 2 A2(g)+ 2 B2(g)⇌ 4 AB(g)is ________.

Accepted Answer

A)    
B) Kc4  
C)      
D)    
E) Kc2  
A)    
B) Kc4  
C)      
D)    
E) Kc2  E

Question 4

The equilibrium constant,Kp,equals 3.40 for the isomerization reaction:
Cis-2-butene ⇌ trans-2-butene
If a flask initially contains 0.250 bar of cis-2-butene and 0.165 bar of trans-2-butene,what is the equilibrium pressure of each gas?

Accepted Answer

A) P(cis-2-butene)= 0.0485 bar and P(trans-2-butene)= 0.165 bar 
B) P(cis-2-butene)= 0.0458 bar and P(trans-2-butene)= 0.156 bar 
C) P(cis-2-butene)= 0.0735 bar and P(trans-2-butene)= 0.250 bar 
D) P(cis-2-butene)= 0.0943 bar and P(trans-2-butene)= 0.321 bar 
A) P(cis-2-butene)= 0.0485 bar and P(trans-2-butene)= 0.165 bar 
B) P(cis-2-butene)= 0.0458 bar and P(trans-2-butene)= 0.156 bar 
C) P(cis-2-butene)= 0.0735 bar and P(trans-2-butene)= 0.250 bar 
D) P(cis-2-butene)= 0.0943 bar and P(trans-2-butene)= 0.321 bar

Question 5

For the reaction:
3 Fe(s)+ 4 H2O(g)⇌ Fe3O4(s)+ 4 H2(g)
Write the expression for Kp.

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 6

Consider the equilibrium system: N2O4(g)⇌ 2 NO2(g)for which Kp = 0.1134 at 25 °C and ΔrH° = 58.03 kJ/mol.Assume that 1 mole of N2O4 and 2 moles of NO2 are introduced into a 5.0 liter container.What will be the equilibrium value of [N2O]?

Accepted Answer

A) 0.928 M 
B) 0.0822 M 
C) 0.358 M 
D) 0.379 M 
E) 0.042 M 
A) 0.928 M 
B) 0.0822 M 
C) 0.358 M 
D) 0.379 M 
E) 0.042 M

Question 7

Which of the following equilibrium constants-reaction types is INCORRECT?

Accepted Answer

A) 1.4 × 1083 equilibrium reaction-goes to completion. 
B) 1.6 × 10-23 equilibrium reaction-does not occur. 
C) 1.8 × 10-5 equilibrium reaction-more reactants than products at equilibrium. 
D) 1.0 equilibrium reaction-equal amounts of products and reactants. 
E) 3.2 × 103 equilibrium reaction-more reactants than products at equilibrium. 
A) 1.4 × 1083 equilibrium reaction-goes to completion. 
B) 1.6 × 10-23 equilibrium reaction-does not occur. 
C) 1.8 × 10-5 equilibrium reaction-more reactants than products at equilibrium. 
D) 1.0 equilibrium reaction-equal amounts of products and reactants. 
E) 3.2 × 103 equilibrium reaction-more reactants than products at equilibrium.

Question 8

At a certain temperature the equilibrium constant,Kc,equals 0.11 for the reaction:
2 ICl(g)⇌ I2(g)+ Cl2(g)
What is the equilibrium concentration of ICl if 0.45 mol of I2 and 0.45 mol of Cl2 are initially mixed in a 2.0 L flask?

Accepted Answer

A) 0.14 mol L-1 
B) 0.17 mol L-1 
C) 0.27 mol L-1 
D) 0.34 mol L-1 
A) 0.14 mol L-1 
B) 0.17 mol L-1 
C) 0.27 mol L-1 
D) 0.34 mol L-1

Question 9

Choose the INCORRECT statement.

Accepted Answer

A) A certain amount of energy,called the activation energy,must be available if a reaction is to take place. 
B) A reversible chemical reaction is one in which equilibrium is never established due to the constant decomposition of the products. 
C) When the rate of the reverse reaction equals the rate of the forward reaction,equilibrium has been established. 
D) Changes in temperature will change the value of an equilibrium constant. 
E) Chemical equilibrium is a dynamic equilibrium. 
A) A certain amount of energy,called the activation energy,must be available if a reaction is to take place. 
B) A reversible chemical reaction is one in which equilibrium is never established due to the constant decomposition of the products. 
C) When the rate of the reverse reaction equals the rate of the forward reaction,equilibrium has been established. 
D) Changes in temperature will change the value of an equilibrium constant. 
E) Chemical equilibrium is a dynamic equilibrium.

Question 10

Consider the equilibrium system: N2O4(g)⇌ 2 NO2(g)for which Kp = 0.1134 at 25 °C and ΔrH° = 58.03 kJ/mol.Assuming that the total pressure inside the container is 10 atm at equilibrium and that initially only N2O4 was present inside the container,compute  
At equilibrium.

Accepted Answer

A) 7.98 atm 
B) 8.88 atm 
C) 1.12 atm 
D) 1.01 atm 
E) 8.99 atm 
A) 7.98 atm 
B) 8.88 atm 
C) 1.12 atm 
D) 1.01 atm 
E) 8.99 atm

Question 11

In a system in equilibrium,two opposing reactions occur at equal rates.

Accepted Answer

A) True 
 B)False

Question 12

For the reaction CO(g)+ 3 H2(g)⇌ H2O(g)+ CH4(g),Kc = 190 at 1000 K.If a vessel is filled with these gases such that the initial concentrations are [CO] = 0.036 M,[H2] = 0.045 M,[H2O] = 0.020,M and [CH4] = 0.031 M,in which direction will a reaction occur and why?

Accepted Answer

A) toward products because Qc = 0.38 
B) toward reactants because Qc = 0.24 
C) toward products because Qc = 4.1 
D) toward reactants because Qc = 61 
E) it is at equilibrium because Qc = 190 
A) toward products because Qc = 0.38 
B) toward reactants because Qc = 0.24 
C) toward products because Qc = 4.1 
D) toward reactants because Qc = 61 
E) it is at equilibrium because Qc = 190

Question 13

Write the equilibrium constant expression for the following reaction:
2 KI(aq)+ H2O2(aq)⇌ 2 KOH(aq)+ I2(aq)

Accepted Answer

A) Kc =   
B) Kc = [I2] 
C) Kc = [I2]2  
D) Kc =   
E) Kc =   
A) Kc =   
B) Kc = [I2] 
C) Kc = [I2]2  
D) Kc =   
E) Kc =

Question 14

For the reaction CO(g)+ 3 H2(g)⇌ H2O(g)+ CH4(g),Kc = 190 at 1000 K.If a vessel is filled with these gases such that the initial concentrations are [CO] = 0.025 M,[H2] = 0.045 M,[H2O] = 0.025,M and [CH4] = 0.046 M,in which direction will a reaction occur and why?

Accepted Answer

A) toward products because Qc = 0.17 
B) toward reactants because Qc = 0.0029 
C) toward products because Qc = 0.35 
D) toward reactants because Qc = 505 
E) it is at equilibrium because Qc = 1 
A) toward products because Qc = 0.17 
B) toward reactants because Qc = 0.0029 
C) toward products because Qc = 0.35 
D) toward reactants because Qc = 505 
E) it is at equilibrium because Qc = 1

Question 15

Equilibrium reactions are noted by a single straight arrow for a yield sign.

Accepted Answer

A) True 
 B)False

Question 16

For the following chemical equilibrium,Kp = 4.6 × 10-14 at 25 °C,find the value of Kc for this reaction at 25 °C.
2 Cl2(g)+ 2 H2O(g)⇌ 4 HCl(g)+ O2(g)

Accepted Answer

A) Kc = 1.9 × 10-15  
B) Kc = 2.2 × 10-14  
C) Kc = 1.1 × 10-12  
D) Kc = 9.4 × 10-14  
E) Kc = 4.6 × 10-14  
A) Kc = 1.9 × 10-15  
B) Kc = 2.2 × 10-14  
C) Kc = 1.1 × 10-12  
D) Kc = 9.4 × 10-14  
E) Kc = 4.6 × 10-14

Question 17

Kc is 1.67 × 1020 at 25 °C for the formation of iron(III)oxalate complex ion:
Fe3+(aq)+ 3C2O42-(aq)⇌ [Fe(C2O4)3]3-(aq)
If 0.0200 mol L-1 Fe3+ is initially mixed with 1.00 mol L-1 oxalate ion,what is the concentration of Fe3+ ion at equilibrium?

Accepted Answer

A) 1.44 × 10-22 mol L-1 
B) 0.0100 mol L-1 
C) 8.35 × 1019 mol L-1 
D) 6.94 × 1021 mol L-1 
A) 1.44 × 10-22 mol L-1 
B) 0.0100 mol L-1 
C) 8.35 × 1019 mol L-1 
D) 6.94 × 1021 mol L-1

Question 18

Consider the reaction:
2 SO2(g)+ O2(g)⇌ 2 SO3(g),ΔrH° = -196.6 kJ/mol
The equilibrium is displaced to the left if:

Accepted Answer

A) some sulfur trioxide is removed 
B) the temperature is raised 
C) some sulfur dioxide is added 
D) the pressure is raised 
E) the temperature is lowered 
A) some sulfur trioxide is removed 
B) the temperature is raised 
C) some sulfur dioxide is added 
D) the pressure is raised 
E) the temperature is lowered

Question 19

Consider the following reaction occurring at 960 K:
CO2(g)+ H2(g)⇌ CO(g)+ H2O(g)
At equilibrium,the concentrations of reactants and products are: [CO2] = 0.0400 M,[H2] = 0.0220 M,[CO] = 0.0240 M,and [H2O] = 0.0190 M.This equilibrium is perturbed by adding CO2(g)to the system such that when a new equilibrium is reached,the concentration of CO2 is 0.050 M.What is the concentration of H2(g)at this equilibrium?

Accepted Answer

A) 0.050 M 
B) 0.482 M 
C) 0.462 M 
D) 0.300 M 
E) 0.0504 M 
A) 0.050 M 
B) 0.482 M 
C) 0.462 M 
D) 0.300 M 
E) 0.0504 M

Question 20

Consider the equilibrium system: N2O4(g)⇌ 2 NO2(g)for which Kp = 0.1134 at 25 °C and ΔrH° = 58.03 kJ/mol.Assuming that the total pressure inside the container is 1.00 atm at equilibrium and that initially only N2O4 was present inside the container,compute  
At equilibrium.

Accepted Answer

A) 0.398 atm 
B) 0.113 atm 
C) 0.602 atm 
D) 0.285 atm 
E) 0.715 atm 
A) 0.398 atm 
B) 0.113 atm 
C) 0.602 atm 
D) 0.285 atm 
E) 0.715 atm

Exam 15: Principles of Chemical Equilibrium

Write the equilibrium constant expression for the reaction: 3 Sn(s)+ 4 HNO3(aq)+ H2O(l)⇌ 3 H2SnO3(s)+ 4 NO(g)

Consider the following hypothetical equilibrium reaction: A2(g)+ B2(g)⇌ 2 AB(g) where Kc = The equilibrium constant for the reaction: 2 A2(g)+ 2 B2(g)⇌ 4 AB(g)is ________.

The equilibrium constant,Kp,equals 3.40 for the isomerization reaction: Cis-2-butene ⇌ trans-2-butene If a flask initially contains 0.250 bar of cis-2-butene and 0.165 bar of trans-2-butene,what is the equilibrium pressure of each gas?

For the reaction: 3 Fe(s)+ 4 H2O(g)⇌ Fe3O4(s)+ 4 H2(g) Write the expression for Kp.

Consider the equilibrium system: N2O4(g)⇌ 2 NO2(g)for which Kp = 0.1134 at 25 °C and ΔrH° = 58.03 kJ/mol.Assume that 1 mole of N2O4 and 2 moles of NO2 are introduced into a 5.0 liter container.What will be the equilibrium value of [N2O]?

Which of the following equilibrium constants-reaction types is INCORRECT?

At a certain temperature the equilibrium constant,Kc,equals 0.11 for the reaction: 2 ICl(g)⇌ I2(g)+ Cl2(g) What is the equilibrium concentration of ICl if 0.45 mol of I2 and 0.45 mol of Cl2 are initially mixed in a 2.0 L flask?

Choose the INCORRECT statement.

Consider the equilibrium system: N2O4(g)⇌ 2 NO2(g)for which Kp = 0.1134 at 25 °C and ΔrH° = 58.03 kJ/mol.Assuming that the total pressure inside the container is 10 atm at equilibrium and that initially only N2O4 was present inside the container,compute At equilibrium.

In a system in equilibrium,two opposing reactions occur at equal rates.

For the reaction CO(g)+ 3 H2(g)⇌ H2O(g)+ CH4(g),Kc = 190 at 1000 K.If a vessel is filled with these gases such that the initial concentrations are [CO] = 0.036 M,[H2] = 0.045 M,[H2O] = 0.020,M and [CH4] = 0.031 M,in which direction will a reaction occur and why?

Write the equilibrium constant expression for the following reaction: 2 KI(aq)+ H2O2(aq)⇌ 2 KOH(aq)+ I2(aq)

For the reaction CO(g)+ 3 H2(g)⇌ H2O(g)+ CH4(g),Kc = 190 at 1000 K.If a vessel is filled with these gases such that the initial concentrations are [CO] = 0.025 M,[H2] = 0.045 M,[H2O] = 0.025,M and [CH4] = 0.046 M,in which direction will a reaction occur and why?

Equilibrium reactions are noted by a single straight arrow for a yield sign.

For the following chemical equilibrium,Kp = 4.6 × 10-14 at 25 °C,find the value of Kc for this reaction at 25 °C. 2 Cl2(g)+ 2 H2O(g)⇌ 4 HCl(g)+ O2(g)

Kc is 1.67 × 1020 at 25 °C for the formation of iron(III)oxalate complex ion: Fe3+(aq)+ 3C2O42-(aq)⇌ [Fe(C2O4)3]3-(aq) If 0.0200 mol L-1 Fe3+ is initially mixed with 1.00 mol L-1 oxalate ion,what is the concentration of Fe3+ ion at equilibrium?

Consider the reaction: 2 SO2(g)+ O2(g)⇌ 2 SO3(g),ΔrH° = -196.6 kJ/mol The equilibrium is displaced to the left if:

Consider the equilibrium system: N2O4(g)⇌ 2 NO2(g)for which Kp = 0.1134 at 25 °C and ΔrH° = 58.03 kJ/mol.Assuming that the total pressure inside the container is 1.00 atm at equilibrium and that initially only N2O4 was present inside the container,compute At equilibrium.

Matter: Its Properties and Measurement

Atoms and the Atomic Theory

Chemical Compounds

Chemical Reactions

Introduction to Reactions in Aqueous Solutions

Gases

Thermochemistry

Electrons in Atoms

The Periodic Table and Some Atomic Properties

Chemical Bonding I: Basic Concepts

Chemical Bonding Ii: Valence Bond and Molecular Orbital Theories

Intermolecular Forces: Liquids and Solids

Spontaneous Change: Entropy and Gibbs Energy

Solutions and Their Physical Properties

Acids and Bases

Additional Aspects of Acidbase Equilibria

Solubility and Complex-Ion Equilibria

Electrochemistry

Chemical Kinetics

Chemistry of the Main-Group Elements I: Groups 1,2,13,and 14

Chemistry of the Main-Group Elements Ii: Groups 18,17,16,15,and Hydrogen

The Transition Elements

Complex Ions and Coordination Compounds

Nuclear Chemistry

Structures of Organic Compounds

Reactions of Organic Compounds

Chemistry of the Living State

Filters

Write the equilibrium constant expression for the reaction: 3 Sn(s)+ 4 HNO₃(aq)+ H₂O(l)⇌ 3 H₂SnO₃(s)+ 4 NO(g)

Consider the following hypothetical equilibrium reaction: A₂(g)+ B₂(g)⇌ 2 AB(g)where K_c = The equilibrium constant for the reaction: 2 A₂(g)+ 2 B₂(g)⇌ 4 AB(g)is ________.

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 bar of cis-2-butene and 0.165 bar of trans-2-butene,what is the equilibrium pressure of each gas?

For the reaction: 3 Fe(s)+ 4 H₂O(g)⇌ Fe₃O₄(s)+ 4 H₂(g) Write the expression for Kp.

Consider the equilibrium system: N₂O₄(g)⇌ 2 NO₂(g)for which K_p = 0.1134 at 25 °C and Δ_rH° = 58.03 kJ/mol.Assume that 1 mole of N₂O₄ and 2 moles of NO₂ are introduced into a 5.0 liter container.What will be the equilibrium value of [N₂O]?

At a certain temperature the equilibrium constant,K_c,equals 0.11 for the reaction: 2 ICl(g)⇌ I₂(g)+ Cl₂(g) What is the equilibrium concentration of ICl if 0.45 mol of I₂ and 0.45 mol of Cl₂ are initially mixed in a 2.0 L flask?

Consider the equilibrium system: N₂O₄(g)⇌ 2 NO₂(g)for which K_p = 0.1134 at 25 °C and Δ_rH° = 58.03 kJ/mol.Assuming that the total pressure inside the container is 10 atm at equilibrium and that initially only N₂O₄ was present inside the container,compute At equilibrium.

For the reaction CO(g)+ 3 H₂(g)⇌ H₂O(g)+ CH₄(g),K_c = 190 at 1000 K.If a vessel is filled with these gases such that the initial concentrations are [CO] = 0.036 M,[H₂] = 0.045 M,[H₂O] = 0.020,M and [CH₄] = 0.031 M,in which direction will a reaction occur and why?

Write the equilibrium constant expression for the following reaction: 2 KI(aq)+ H₂O₂(aq)⇌ 2 KOH(aq)+ I₂(aq)

For the reaction CO(g)+ 3 H₂(g)⇌ H₂O(g)+ CH₄(g),K_c = 190 at 1000 K.If a vessel is filled with these gases such that the initial concentrations are [CO] = 0.025 M,[H₂] = 0.045 M,[H₂O] = 0.025,M and [CH₄] = 0.046 M,in which direction will a reaction occur and why?

For the following chemical equilibrium,K_p = 4.6 × 10^-14 at 25 °C,find the value of K_c for this reaction at 25 °C. 2 Cl₂(g)+ 2 H₂O(g)⇌ 4 HCl(g)+ O₂(g)

K_c is 1.67 × 10²⁰ at 25 °C for the formation of iron(III)oxalate complex ion: Fe³⁺(aq)+ 3C₂O₄^2-(aq)⇌ [Fe(C₂O₄)₃]^3-(aq) If 0.0200 mol L^-1 Fe³⁺ is initially mixed with 1.00 mol L^-1 oxalate ion,what is the concentration of Fe³⁺ ion at equilibrium?

Consider the reaction: 2 SO₂(g)+ O₂(g)⇌ 2 SO₃(g),Δ_rH° = -196.6 kJ/mol The equilibrium is displaced to the left if:

Consider the equilibrium system: N₂O₄(g)⇌ 2 NO₂(g)for which K_p = 0.1134 at 25 °C and Δ_rH° = 58.03 kJ/mol.Assuming that the total pressure inside the container is 1.00 atm at equilibrium and that initially only N₂O₄ was present inside the container,compute At equilibrium.