Question 1

Write the mass-action expression,Qc,for the following chemical reaction.
Fe3+(aq)+ 3OH-(aq)  
Fe(OH)3(s)

Accepted Answer

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

Question 2

The reaction of nitric oxide to form dinitrogen oxide and nitrogen dioxide is exothermic.
3NO(g)  
N2O(g)+ NO2(g)+ heat
What effect will be seen if the temperature of the system at equilibrium is raised by 25°C?

Accepted Answer

A) The partial pressure of NO will increase. 
B) The partial pressure of NO will decrease. 
C) The partial pressure of NO2 will increase. 
D) The partial pressures of NO and N2O will increase. 
E) All three partial pressures will increase. 
A) The partial pressure of NO will increase. 
B) The partial pressure of NO will decrease. 
C) The partial pressure of NO2 will increase. 
D) The partial pressures of NO and N2O will increase. 
E) All three partial pressures will increase.

Question 3

Write the mass-action expression,Qc,for the following chemical reaction.
3ClO2-(aq)  
2ClO3-(aq)+ Cl-(aq)

Accepted Answer

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

Question 4

Consider the following two equilibria and their respective equilibrium constants:
(1)NO(g)+  
O2(g)  
NO2(g)
(2)2NO2(g)  
2NO(g)+ O2(g)
Which one of the following is the correct relationship between the equilibrium constants K1 and K2?

Accepted Answer

A) K2 = 2/K1 
B) K2 = (1/K1)2 
C) K2 = -K1/2 
D) K2 = 1/(2K1) 
E) K2 = 1/(2K1)2 
A) K2 = 2/K1 
B) K2 = (1/K1)2 
C) K2 = -K1/2 
D) K2 = 1/(2K1) 
E) K2 = 1/(2K1)2

Question 5

The following reaction is at equilibrium in a sealed container.
 
Which,if any,of the following actions will increase the value of the equilibrium constant,Kc?

Accepted Answer

A) adding a catalyst 
B) adding more N2 
C) increasing the pressure 
D) lowering the temperature 
E) None of these choices is correct. 
A) adding a catalyst 
B) adding more N2 
C) increasing the pressure 
D) lowering the temperature 
E) None of these choices is correct.

Question 6

Write the mass-action expression,Qc,for the following chemical reaction.
Zn(s)+ 2Ag+(aq)  
Zn2+(aq)+ 2Ag(s)

Accepted Answer

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

Question 7

Consider the equilibrium
H2(g)+ Br2(g)   
2HBr(g)
To a 20.0 L flask are added 0.100 moles of H2 and 0.200 moles of HBr.The equilibrium constant for this reaction is 989.Calculate the number of moles of Br2 in the flask when equilibrium is established.Make any reasonable approximation,clearly stating what that approximation is.

Accepted Answer

~ 4.0 @#LAT-DLM& 10^-4 mol of

Question 8

A container was charged with hydrogen,nitrogen,and ammonia gases at 120°C and the system was allowed to reach equilibrium.What will happen if the volume of the container is increased at constant temperature?
3H2(g)+ N2(g)  
2NH3(g)

Accepted Answer

A) There will be no effect. 
B) More ammonia will be produced at the expense of hydrogen and nitrogen. 
C) Hydrogen and nitrogen will be produced at the expense of ammonia. 
D) The equilibrium constant will increase. 
E) The equilibrium constant will decrease. 
A) There will be no effect. 
B) More ammonia will be produced at the expense of hydrogen and nitrogen. 
C) Hydrogen and nitrogen will be produced at the expense of ammonia. 
D) The equilibrium constant will increase. 
E) The equilibrium constant will decrease.

Question 9

Ammonium iodide dissociates reversibly to ammonia and hydrogen iodide.
NH4I(s)  
NH3(g)+ HI(g)
At 400°C,Kp = 0.215.Calculate the partial pressure of ammonia at equilibrium when a sufficient quantity of ammonium iodide is heated to 400°C.

Accepted Answer

A) 0.103 atm 
B) 0.215 atm 
C) 0.232 atm 
D) 0.464 atm 
E) 2.00 atm 
A) 0.103 atm 
B) 0.215 atm 
C) 0.232 atm 
D) 0.464 atm 
E) 2.00 atm

Question 10

The reaction system
POCl3(g)  
POCl(g)+ Cl2(g)
Is at equilibrium.Which of the following statements describes the behavior of the system if POCl is added to the container?

Accepted Answer

A) The forward reaction will proceed to establish equilibrium. 
B) The reverse reaction will proceed to establish equilibrium. 
C) The partial pressures of POCl3 and POCl will remain steady while the partial pressure of chlorine increases. 
D) The partial pressure of chlorine remains steady while the partial pressures of POCl3 and POCl increase. 
E) The partial pressure of chlorine will increase while the partial pressure of POCl decreases. 
A) The forward reaction will proceed to establish equilibrium. 
B) The reverse reaction will proceed to establish equilibrium. 
C) The partial pressures of POCl3 and POCl will remain steady while the partial pressure of chlorine increases. 
D) The partial pressure of chlorine remains steady while the partial pressures of POCl3 and POCl increase. 
E) The partial pressure of chlorine will increase while the partial pressure of POCl decreases.

Question 11

Changing the amount of reactant or product in an equilibrium reaction will always change the equilibrium position,regardless of the physical state of the substance involved.

Accepted Answer

A) True 
 B)False

Question 12

There is a direct correlation between the speed of a reaction and its equilibrium constant.

Accepted Answer

A) True 
 B)False

Question 13

In order to write the correct mass-action expression for a reaction one must

Accepted Answer

A) know the kinetic rate law for the reaction. 
B) know the mechanism for the reaction. 
C) have a properly balanced chemical equation. 
D) have values for the concentrations of the reactants. 
E) know the limiting reactant. 
A) know the kinetic rate law for the reaction. 
B) know the mechanism for the reaction. 
C) have a properly balanced chemical equation. 
D) have values for the concentrations of the reactants. 
E) know the limiting reactant.

Question 14

Nitrogen dioxide can dissociate to nitric oxide and oxygen.
 
Under which reaction conditions would you expect to produce the largest amount of oxygen?

Accepted Answer

A) high temperature,high pressure 
B) low temperature,high pressure 
C) high temperature,low pressure 
D) low temperature,low pressure 
E) none of these,unless a catalyst is present 
A) high temperature,high pressure 
B) low temperature,high pressure 
C) high temperature,low pressure 
D) low temperature,low pressure 
E) none of these,unless a catalyst is present

Question 15

Magnesium carbonate dissociates to magnesium oxide and carbon dioxide at elevated temperatures.
MgCO3(s)  
MgO(s)+ CO2(g)
A reaction vessel contains these compounds in equilibrium at 300°C.What will happen if the volume of the container is reduced by 25% at 300°C?

Accepted Answer

A) The partial pressure of carbon dioxide present at equilibrium will increase. 
B) The partial pressure of carbon dioxide present at equilibrium will decrease. 
C) The partial pressure of carbon dioxide at equilibrium will be unchanged. 
D) The equilibrium constant will have to decrease to compensate for the decrease in volume. 
E) More information is needed in order to make a valid judgment. 
A) The partial pressure of carbon dioxide present at equilibrium will increase. 
B) The partial pressure of carbon dioxide present at equilibrium will decrease. 
C) The partial pressure of carbon dioxide at equilibrium will be unchanged. 
D) The equilibrium constant will have to decrease to compensate for the decrease in volume. 
E) More information is needed in order to make a valid judgment.

Question 16

At 450°C,tert-butyl alcohol decomposes into water and isobutene.
(CH3)3COH(g)  
(CH3)2CCH2(g)+ H2O(g)
A reaction vessel contains these compounds at equilibrium.What will happen if the volume of the container is reduced by 50% at constant temperature?

Accepted Answer

A) The forward reaction will proceed to reestablish equilibrium. 
B) The reverse reaction will proceed to reestablish equilibrium. 
C) No change occurs. 
D) The equilibrium constant will increase. 
E) The equilibrium constant will decrease. 
A) The forward reaction will proceed to reestablish equilibrium. 
B) The reverse reaction will proceed to reestablish equilibrium. 
C) No change occurs. 
D) The equilibrium constant will increase. 
E) The equilibrium constant will decrease.

Question 17

The equilibrium constant,Kp ,for the reaction
CO(g)+ H2O(g)  
CO2(g)+ H2(g)
At 986°C is 0.63.A rigid cylinder at that temperature contains 1.2 atm of carbon monoxide,0.20 atm of water vapor,0.30 atm of carbon dioxide,and 0.27 atm of hydrogen.Is the system at equilibrium?

Accepted Answer

A) Yes. 
B) No,the forward reaction must proceed to establish equilibrium. 
C) No,the reverse reaction must proceed to establish equilibrium. 
D) The volume of the container must be known before deciding. 
E) The starting concentrations of all substances must be known before deciding. 
A) Yes. 
B) No,the forward reaction must proceed to establish equilibrium. 
C) No,the reverse reaction must proceed to establish equilibrium. 
D) The volume of the container must be known before deciding. 
E) The starting concentrations of all substances must be known before deciding.

Question 18

Consider the reversible reaction: 2NO2(g)  
N2O4(g)
If the concentrations of both NO2 and N2O4 are 0.016 mol L-1,what is the value of Qc?

Accepted Answer

A) 0.016 
B) 0.50 
C) 1.0 
D) 2.0 
E) 63 
A) 0.016 
B) 0.50 
C) 1.0 
D) 2.0 
E) 63

Question 19

For some gas-phase reactions,Kp = Kc.

Accepted Answer

A) True 
 B)False

Question 20

The equilibrium constant for reaction (1)below is 276.Under the same conditions,what is the equilibrium constant of reaction (2)?
(1)  
X2(g)+  
Y2(g)  
XY(g)
(2)2XY(g)  
X2(g)+ Y2(g)

Accepted Answer

A) 6.02 $\times$ 10-2 
B) 7.25 $\times$ 10-3 
C) 3.62 $\times$ 10-3 
D) 1.31 $\times$ 10-5 
E) None of these choices is correct. 
A) 6.02 $\times$ 10-2 
B) 7.25 $\times$ 10-3 
C) 3.62 $\times$ 10-3 
D) 1.31 $\times$ 10-5 
E) None of these choices is correct.

Exam 17: Equilibrium: the Extent of Chemical Reactions

Write the mass-action expression,Qc,for the following chemical reaction. Fe3+(aq)+ 3OH-(aq) Fe(OH)3(s)

The reaction of nitric oxide to form dinitrogen oxide and nitrogen dioxide is exothermic. 3NO(g) N2O(g)+ NO2(g)+ heat What effect will be seen if the temperature of the system at equilibrium is raised by 25°C?

Write the mass-action expression,Qc,for the following chemical reaction. 3ClO2-(aq) 2ClO3-(aq)+ Cl-(aq)

Consider the following two equilibria and their respective equilibrium constants: (1)NO(g)+ O2(g) NO2(g) (2)2NO2(g) 2NO(g)+ O2(g) Which one of the following is the correct relationship between the equilibrium constants K1 and K2?

The following reaction is at equilibrium in a sealed container. Which,if any,of the following actions will increase the value of the equilibrium constant,Kc?

Write the mass-action expression,Qc,for the following chemical reaction. Zn(s)+ 2Ag+(aq) Zn2+(aq)+ 2Ag(s)

A container was charged with hydrogen,nitrogen,and ammonia gases at 120°C and the system was allowed to reach equilibrium.What will happen if the volume of the container is increased at constant temperature? 3H2(g)+ N2(g) 2NH3(g)

Ammonium iodide dissociates reversibly to ammonia and hydrogen iodide. NH4I(s) NH3(g)+ HI(g) At 400°C,Kp = 0.215.Calculate the partial pressure of ammonia at equilibrium when a sufficient quantity of ammonium iodide is heated to 400°C.

The reaction system POCl3(g) POCl(g)+ Cl2(g) Is at equilibrium.Which of the following statements describes the behavior of the system if POCl is added to the container?

Changing the amount of reactant or product in an equilibrium reaction will always change the equilibrium position,regardless of the physical state of the substance involved.

There is a direct correlation between the speed of a reaction and its equilibrium constant.

In order to write the correct mass-action expression for a reaction one must

Nitrogen dioxide can dissociate to nitric oxide and oxygen. Under which reaction conditions would you expect to produce the largest amount of oxygen?

Magnesium carbonate dissociates to magnesium oxide and carbon dioxide at elevated temperatures. MgCO3(s) MgO(s)+ CO2(g) A reaction vessel contains these compounds in equilibrium at 300°C.What will happen if the volume of the container is reduced by 25% at 300°C?

At 450°C,tert-butyl alcohol decomposes into water and isobutene. (CH3)3COH(g) (CH3)2CCH2(g)+ H2O(g) A reaction vessel contains these compounds at equilibrium.What will happen if the volume of the container is reduced by 50% at constant temperature?

The equilibrium constant,Kp ,for the reaction CO(g)+ H2O(g) CO2(g)+ H2(g) At 986°C is 0.63.A rigid cylinder at that temperature contains 1.2 atm of carbon monoxide,0.20 atm of water vapor,0.30 atm of carbon dioxide,and 0.27 atm of hydrogen.Is the system at equilibrium?

Consider the reversible reaction: 2NO2(g) N2O4(g) If the concentrations of both NO2 and N2O4 are 0.016 mol L-1,what is the value of Qc?

For some gas-phase reactions,Kp = Kc.

The equilibrium constant for reaction (1)below is 276.Under the same conditions,what is the equilibrium constant of reaction (2)? (1) X2(g)+ Y2(g) XY(g) (2)2XY(g) X2(g)+ Y2(g)

Keys to the Study of Chemistry

The Components of Matter

Stoichiometry of Formulas and Equations

Three Major Classes of Chemical Reactions

Gases and the Kinetic-Molecular Theory

Thermochemistry: Energy Flow and Chemical Change

Quantum Theory and Atomic Structure

Electron Configuration and Chemical Periodicity

Models of Chemical Bonding

The Shapes of Molecules

Theories of Covalent Bonding

Intermolecular Forces: Liquids,solids,and Phase Changes

The Properties of Solutions

The Main-Group Elements: Applying Principles of Bonding and Structure

Organic Compounds and the Atomic Properties of Carbon

Kinetics: Rates and Mechanisms of Chemical Reactions

Acid-Base Equilibria

Ionic Equilibria in Aqueous Systems

Thermodynamics: Entropy, free Energy, and the Direction of Chemical Reactions

Electrochemistry: Chemical Change and Electrical Work

The Transition Elements and Their Coordination Compounds

Nuclear Reactions and Their Applications

Filters

Write the mass-action expression,Q_c,for the following chemical reaction. Fe³⁺(aq)+ 3OH^-(aq) Fe(OH)₃(s)

The reaction of nitric oxide to form dinitrogen oxide and nitrogen dioxide is exothermic. 3NO(g) N₂O(g)+ NO₂(g)+ heat What effect will be seen if the temperature of the system at equilibrium is raised by 25°C?

Write the mass-action expression,Q_c,for the following chemical reaction. 3ClO₂^-(aq) 2ClO₃^-(aq)+ Cl^-(aq)

Consider the following two equilibria and their respective equilibrium constants: (1)NO(g)+ O₂(g) NO₂(g) (2)2NO₂(g) 2NO(g)+ O₂(g) Which one of the following is the correct relationship between the equilibrium constants K₁ and K₂?

The following reaction is at equilibrium in a sealed container. Which,if any,of the following actions will increase the value of the equilibrium constant,K_c?

Write the mass-action expression,Q_c,for the following chemical reaction. Zn(s)+ 2Ag⁺(aq) Zn²⁺(aq)+ 2Ag(s)

A container was charged with hydrogen,nitrogen,and ammonia gases at 120°C and the system was allowed to reach equilibrium.What will happen if the volume of the container is increased at constant temperature? 3H₂(g)+ N₂(g) 2NH₃(g)

Ammonium iodide dissociates reversibly to ammonia and hydrogen iodide. NH₄I(s) NH₃(g)+ HI(g) At 400°C,K_p = 0.215.Calculate the partial pressure of ammonia at equilibrium when a sufficient quantity of ammonium iodide is heated to 400°C.

The reaction system POCl₃(g) POCl(g)+ Cl₂(g) Is at equilibrium.Which of the following statements describes the behavior of the system if POCl is added to the container?

Magnesium carbonate dissociates to magnesium oxide and carbon dioxide at elevated temperatures. MgCO₃(s) MgO(s)+ CO₂(g) A reaction vessel contains these compounds in equilibrium at 300°C.What will happen if the volume of the container is reduced by 25% at 300°C?

At 450°C,tert-butyl alcohol decomposes into water and isobutene. (CH₃)₃COH(g) (CH₃)₂CCH₂(g)+ H₂O(g) A reaction vessel contains these compounds at equilibrium.What will happen if the volume of the container is reduced by 50% at constant temperature?

The equilibrium constant,K_p ,for the reaction CO(g)+ H₂O(g) CO₂(g)+ H₂(g) At 986°C is 0.63.A rigid cylinder at that temperature contains 1.2 atm of carbon monoxide,0.20 atm of water vapor,0.30 atm of carbon dioxide,and 0.27 atm of hydrogen.Is the system at equilibrium?

Consider the reversible reaction: 2NO₂(g) N₂O₄(g) If the concentrations of both NO₂ and N₂O₄ are 0.016 mol L^-1,what is the value of Q_c?

For some gas-phase reactions,K_p = K_c.

The equilibrium constant for reaction (1)below is 276.Under the same conditions,what is the equilibrium constant of reaction (2)? (1) X₂(g)+ Y₂(g) XY(g) (2)2XY(g) X₂(g)+ Y₂(g)