Question 1

Choose the correct equilibrium constant expression for the equilibrium 
CO(g)+ Cl2(g)   COCl2(g).

Accepted Answer

A) K =   
B) K =   
C) K =   
D) K =   
E) K =   
A) K =   
B) K =   
C) K =   
D) K =   
E) K =   A

Question 2

Which of the following correctly expresses Ka for the weak acid HF(aq)?

Accepted Answer

A) Ka = [HF] 
B) Ka =   
C) Ka =   
D) Ka = [H+][F-] 
E) Ka =   
A) Ka = [HF] 
B) Ka =   
C) Ka =   
D) Ka = [H+][F-] 
E) Ka =   B

Question 3

1.9 mole of NOCl is placed in a 1.00 L vessel at a certain temperature.It reacts until equilibrium is reached according to the equation 2 NOCl(g)   2 NO(g)+ Cl2(g)At equilibrium,[NO] = 0.60 M.Calculate the value of K.

Accepted Answer

A) 0.60 
B) 0.14 
C) 0.064 
D) 0.030 
E) 0.36 
A) 0.60 
B) 0.14 
C) 0.064 
D) 0.030 
E) 0.36 C

Question 4

If one is trying to change the amount of reactants and products in a gaseous equilibrium system,which of the following will probably not have the desired effect?

Accepted Answer

A) addition of a catalyst 
B) addition of a reactant 
C) removal of a product 
D) altering the temperature 
E) changing the volume of the container 
A) addition of a catalyst 
B) addition of a reactant 
C) removal of a product 
D) altering the temperature 
E) changing the volume of the container

Question 5

Calculate the molar solubility of magnesium fluoride (Ksp = 6.9 × 10-9)in a solution that also 0.010 M NaF.

Accepted Answer

A) 6.9 × 10-5 M 
B) 6.9 × 10-7 M 
C) 6.9 × 10-11 M 
D) 1.7 × 10-5 M 
E) 3.5 × 10-7 M 
A) 6.9 × 10-5 M 
B) 6.9 × 10-7 M 
C) 6.9 × 10-11 M 
D) 1.7 × 10-5 M 
E) 3.5 × 10-7 M

Question 6

What will happen to the position of equilibrium if the volume of the system is decreased in the reaction shown? 
N2(g)+ 3 H2   2 NH3(g)

Accepted Answer

A) It will shift to the left 
B) There will be no shift in the position of equilibrium 
C) The position will shift left and then return to its original place 
D) It will shift to the right 
E) It will shift so that the system volume is increased again 
A) It will shift to the left 
B) There will be no shift in the position of equilibrium 
C) The position will shift left and then return to its original place 
D) It will shift to the right 
E) It will shift so that the system volume is increased again

Question 7

In writing the expression for the equilibrium constant for a reaction,which of the following should not be done?

Accepted Answer

A) The concentration of products is placed in the numerator. 
B) The concentration of reactants is placed in the denominator. 
C) There are terms for liquids, gases and solutions are included but not solids. 
D) The coefficients from the chemical reaction are the exponents for the concentration term. 
E) All of these are correct and should be observed. 
A) The concentration of products is placed in the numerator. 
B) The concentration of reactants is placed in the denominator. 
C) There are terms for liquids, gases and solutions are included but not solids. 
D) The coefficients from the chemical reaction are the exponents for the concentration term. 
E) All of these are correct and should be observed.

Question 8

What is the pH of a 0.20 M solution of nitrous acid? Ka = 4.5 × 10-4

Accepted Answer

A) 9.02 
B) 4.66 
C) 4.05 
D) 2.02 
E) 0.70 
A) 9.02 
B) 4.66 
C) 4.05 
D) 2.02 
E) 0.70

Question 9

Which of the following is the primary reason for a higher reaction rate at higher temperatures?

Accepted Answer

A) Molecules move faster at higher temperatures, producing more violent collisions 
B) Electrons occupy higher principal energy levels and are therefore more reactive 
C) There is a larger fraction of molecules with sufficient energy to react 
D) Molecules increase in size with increasing temperature, providing more surface area for potential collisions 
E) The higher temperature creates a lower activation energy, so more molecules can pass over the potential energy barrier 
A) Molecules move faster at higher temperatures, producing more violent collisions 
B) Electrons occupy higher principal energy levels and are therefore more reactive 
C) There is a larger fraction of molecules with sufficient energy to react 
D) Molecules increase in size with increasing temperature, providing more surface area for potential collisions 
E) The higher temperature creates a lower activation energy, so more molecules can pass over the potential energy barrier

Question 10

If an aluminum nitrate solution is added to a sodium fluoride solution the following equilibrium will be reached: Al3+(aq)+ 6 F-(aq)   AlF63-(aq).For this equilibrium,K = 5.0 × 1023.Choose the correct equilibrium constant and the correct direction favored at equilibrium.

Accepted Answer

A) K =   reverse 
B) K =   forward 
C) K =   reverse 
D) K =   forward 
E) K =   forward 
A) K =   reverse 
B) K =   forward 
C) K =   reverse 
D) K =   forward 
E) K =   forward

Question 11

How does a catalyst alter the rate of a reaction?

Accepted Answer

A) Catalysts replace part of the reactants 
B) Catalysts provide the activation energy needed 
C) A catalyst interferes with the attainment of chemical equilibrium 
D) Catalysts provide more heat to the reaction, and the increased temperature leads to an increased reaction rate 
E) Catalysts provide a reaction pathway with a lower energy of activation 
A) Catalysts replace part of the reactants 
B) Catalysts provide the activation energy needed 
C) A catalyst interferes with the attainment of chemical equilibrium 
D) Catalysts provide more heat to the reaction, and the increased temperature leads to an increased reaction rate 
E) Catalysts provide a reaction pathway with a lower energy of activation

Question 12

Choose the correct equilibrium constant expression for the hypothetical equilibrium 
2 A(g)+ 3 B(g)   4 C(g)+ 5 D(g).

Accepted Answer

A) K =   
B) K =   
C) K =   
D) K =   
E) K =   
A) K =   
B) K =   
C) K =   
D) K =   
E) K =

Question 13

Which of the following conditions is not found in a system that is at equilibrium?

Accepted Answer

A) Reactants and products are being converted into one another continually 
B) The forward rate of reaction is equal to the rate of the reverse reaction 
C) The concentration of reactants is equal to the concentration of the products 
D) The system is closed and isolated from its surroundings 
E) The reaction can be represented by an equation with a double arrow 
A) Reactants and products are being converted into one another continually 
B) The forward rate of reaction is equal to the rate of the reverse reaction 
C) The concentration of reactants is equal to the concentration of the products 
D) The system is closed and isolated from its surroundings 
E) The reaction can be represented by an equation with a double arrow

Question 14

Which of the following statements is/are correct?
i.The forward reaction in an equilibrium reaction is exactly the reverse of the reverse reaction
ii.A dynamic equilibrium is established when two molecules collide
iii.As reactant concentrations in a chemical equilibrium reaction decrease,the forward reaction rate declines

Accepted Answer

A) ii only 
B) i and ii 
C) i and iii 
D) ii and iii 
E) i, ii, and iii 
A) ii only 
B) i and ii 
C) i and iii 
D) ii and iii 
E) i, ii, and iii

Question 15

Consider the hypothetical reaction A + 2 B   AB2 at equilibrium.Which is true?

Accepted Answer

A) The reverse reaction rate is at a maximum 
B) The concentration of A must equal the concentration of B 
C) The concentration of A must equal one-half the concentration of B 
D) The forward reaction rate is equal to the reverse reaction rate 
E) The forward reaction rate is equal to the equilibrium reaction rate 
A) The reverse reaction rate is at a maximum 
B) The concentration of A must equal the concentration of B 
C) The concentration of A must equal one-half the concentration of B 
D) The forward reaction rate is equal to the reverse reaction rate 
E) The forward reaction rate is equal to the equilibrium reaction rate

Question 16

What will happen if the temperature is decreased after equilibrium has been established in the reaction below? 
2 C2H6(g)+ 7 O2(g)   4 CO2(g)+ 6 H2O(g)+ 2855 kJ

Accepted Answer

A) There will be no change in the system 
B) The concentration of ethane will increase 
C) The partial pressure of oxygen will increase 
D) The number of water molecules will decrease 
E) More carbon dioxide will form 
A) There will be no change in the system 
B) The concentration of ethane will increase 
C) The partial pressure of oxygen will increase 
D) The number of water molecules will decrease 
E) More carbon dioxide will form

Question 17

If the position of equilibrium shifts to the left,what will happen?

Accepted Answer

A) The concentration of products will increase 
B) The concentration of reactants will increase 
C) The temperature will rise 
D) The temperature will decrease 
E) The concentrations of both products and reactants will increase 
A) The concentration of products will increase 
B) The concentration of reactants will increase 
C) The temperature will rise 
D) The temperature will decrease 
E) The concentrations of both products and reactants will increase

Question 18

Consider the hypothetical reaction A2 + B2   2 AB When will the forward reaction rate be at a maximum,and when will the reverse reaction rate be at a maximum?

Accepted Answer

A) The forward reaction rate will be at a maximum when equilibrium is established, and the reverse reaction rate will be at a maximum when equilibrium is established 
B) The forward reaction rate will be at a maximum when equilibrium is established, and the reverse reaction rate will be at a maximum at time zero 
C) The forward reaction rate will be at a maximum at time zero, and the reverse reaction rate will be at a maximum when equilibrium is established 
D) The forward reaction rate will be at a maximum between time zero and when equilibrium is established, and the reverse reaction rate will be at a maximum when equilibrium is established 
E) The forward reaction rate will be at a maximum when equilibrium is established, and the reverse reaction rate will be at a maximum between time zero and when equilibrium is established 
A) The forward reaction rate will be at a maximum when equilibrium is established, and the reverse reaction rate will be at a maximum when equilibrium is established 
B) The forward reaction rate will be at a maximum when equilibrium is established, and the reverse reaction rate will be at a maximum at time zero 
C) The forward reaction rate will be at a maximum at time zero, and the reverse reaction rate will be at a maximum when equilibrium is established 
D) The forward reaction rate will be at a maximum between time zero and when equilibrium is established, and the reverse reaction rate will be at a maximum when equilibrium is established 
E) The forward reaction rate will be at a maximum when equilibrium is established, and the reverse reaction rate will be at a maximum between time zero and when equilibrium is established

Question 19

Consider the following reaction coordinate diagram.   Which numbered point represents the transition state of the reaction?

Accepted Answer

A) 1 
B) 2 
C) 3 
D) 4 
E) 5 
A) 1 
B) 2 
C) 3 
D) 4 
E) 5

Question 20

Consider the following reaction coordinate diagram.   The energy value corresponding to which point(s)will change if a catalyst is added to this reaction?

Accepted Answer

A) 1 and 5 
B) 1, 3, and 5 
C) 2, 3, and 4 
D) 2 and 4 
E) All will change their energy value. 
A) 1 and 5 
B) 1, 3, and 5 
C) 2, 3, and 4 
D) 2 and 4 
E) All will change their energy value.

Choose the correct equilibrium constant expression for the equilibrium CO(g)+ Cl₂(g) COCl₂(g).

Which of the following correctly expresses K_a for the weak acid HF(aq)?

1.9 mole of NOCl is placed in a 1.00 L vessel at a certain temperature.It reacts until equilibrium is reached according to the equation 2 NOCl(g) 2 NO(g)+ Cl₂(g)At equilibrium,[NO] = 0.60 M.Calculate the value of K.

If one is trying to change the amount of reactants and products in a gaseous equilibrium system,which of the following will probably not have the desired effect?

Calculate the molar solubility of magnesium fluoride (K_sp = 6.9 × 10^-9)in a solution that also 0.010 M NaF.

What will happen to the position of equilibrium if the volume of the system is decreased in the reaction shown? N₂(g)+ 3 H₂ 2 NH₃(g)

In writing the expression for the equilibrium constant for a reaction,which of the following should not be done?

What is the pH of a 0.20 M solution of nitrous acid? K_a = 4.5 × 10^-4

Which of the following is the primary reason for a higher reaction rate at higher temperatures?

If an aluminum nitrate solution is added to a sodium fluoride solution the following equilibrium will be reached: Al³⁺(aq)+ 6 F^-(aq) AlF₆^3-(aq).For this equilibrium,K = 5.0 × 10²³.Choose the correct equilibrium constant and the correct direction favored at equilibrium.

How does a catalyst alter the rate of a reaction?

Choose the correct equilibrium constant expression for the hypothetical equilibrium 2 A(g)+ 3 B(g) 4 C(g)+ 5 D(g).

Which of the following conditions is not found in a system that is at equilibrium?

Consider the hypothetical reaction A + 2 B AB₂ at equilibrium.Which is true?

What will happen if the temperature is decreased after equilibrium has been established in the reaction below? 2 C₂H₆(g)+ 7 O₂(g) 4 CO₂(g)+ 6 H₂O(g)+ 2855 kJ

If the position of equilibrium shifts to the left,what will happen?

Consider the hypothetical reaction A₂ + B₂ 2 AB When will the forward reaction rate be at a maximum,and when will the reverse reaction rate be at a maximum?

Consider the following reaction coordinate diagram. Which numbered point represents the transition state of the reaction?

Consider the following reaction coordinate diagram. The energy value corresponding to which point(s)will change if a catalyst is added to this reaction?

Matter and Energy

Measurement and Chemical Calculations

Introduction to Gases

Atomic Theory: The Nuclear Model of the Atom

Chemical Nomenclature

Chemical Formula Relationships

Chemical Reactions

Chemical Change

Quantity Relationships in Chemical Reactions

Atomic Theory: The Quantum Model of the Atom

Chemical Bonding

Structure and Shape

The Ideal Gas Law and Its Applications

Gases, Liquids, and Solids

Solutions

Acidbase Proton Transferreactions

Oxidationreduction Electron Transferreactions

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Filters

Exam 18: Chemical Equilibrium

Choose the correct equilibrium constant expression for the equilibrium CO(g)+ Cl2(g) COCl2(g).

Which of the following correctly expresses Ka for the weak acid HF(aq)?

1.9 mole of NOCl is placed in a 1.00 L vessel at a certain temperature.It reacts until equilibrium is reached according to the equation 2 NOCl(g) 2 NO(g)+ Cl2(g)At equilibrium,[NO] = 0.60 M.Calculate the value of K.

If one is trying to change the amount of reactants and products in a gaseous equilibrium system,which of the following will probably not have the desired effect?

Calculate the molar solubility of magnesium fluoride (Ksp = 6.9 × 10-9)in a solution that also 0.010 M NaF.

What will happen to the position of equilibrium if the volume of the system is decreased in the reaction shown? N2(g)+ 3 H2 2 NH3(g)

In writing the expression for the equilibrium constant for a reaction,which of the following should not be done?

What is the pH of a 0.20 M solution of nitrous acid? Ka = 4.5 × 10-4

Which of the following is the primary reason for a higher reaction rate at higher temperatures?

If an aluminum nitrate solution is added to a sodium fluoride solution the following equilibrium will be reached: Al3+(aq)+ 6 F-(aq) AlF63-(aq).For this equilibrium,K = 5.0 × 1023.Choose the correct equilibrium constant and the correct direction favored at equilibrium.

How does a catalyst alter the rate of a reaction?

Choose the correct equilibrium constant expression for the hypothetical equilibrium 2 A(g)+ 3 B(g) 4 C(g)+ 5 D(g).

Which of the following conditions is not found in a system that is at equilibrium?

Consider the hypothetical reaction A + 2 B AB2 at equilibrium.Which is true?

What will happen if the temperature is decreased after equilibrium has been established in the reaction below? 2 C2H6(g)+ 7 O2(g) 4 CO2(g)+ 6 H2O(g)+ 2855 kJ

If the position of equilibrium shifts to the left,what will happen?

Consider the hypothetical reaction A2 + B2 2 AB When will the forward reaction rate be at a maximum,and when will the reverse reaction rate be at a maximum?

Consider the following reaction coordinate diagram. Which numbered point represents the transition state of the reaction?

Consider the following reaction coordinate diagram. The energy value corresponding to which point(s)will change if a catalyst is added to this reaction?

Matter and Energy

Measurement and Chemical Calculations

Introduction to Gases

Atomic Theory: The Nuclear Model of the Atom

Chemical Nomenclature

Chemical Formula Relationships

Chemical Reactions

Chemical Change

Quantity Relationships in Chemical Reactions

Atomic Theory: The Quantum Model of the Atom

Chemical Bonding

Structure and Shape

The Ideal Gas Law and Its Applications

Gases, Liquids, and Solids

Solutions

Acidbase Proton Transferreactions

Oxidationreduction Electron Transferreactions

Nuclear Chemistry

Organic Chemistry

Biochemistry

Filters

Choose the correct equilibrium constant expression for the equilibrium CO(g)+ Cl₂(g) COCl₂(g).

Which of the following correctly expresses K_a for the weak acid HF(aq)?

1.9 mole of NOCl is placed in a 1.00 L vessel at a certain temperature.It reacts until equilibrium is reached according to the equation 2 NOCl(g) 2 NO(g)+ Cl₂(g)At equilibrium,[NO] = 0.60 M.Calculate the value of K.

Calculate the molar solubility of magnesium fluoride (K_sp = 6.9 × 10^-9)in a solution that also 0.010 M NaF.

What will happen to the position of equilibrium if the volume of the system is decreased in the reaction shown? N₂(g)+ 3 H₂ 2 NH₃(g)

What is the pH of a 0.20 M solution of nitrous acid? K_a = 4.5 × 10^-4

If an aluminum nitrate solution is added to a sodium fluoride solution the following equilibrium will be reached: Al³⁺(aq)+ 6 F^-(aq) AlF₆^3-(aq).For this equilibrium,K = 5.0 × 10²³.Choose the correct equilibrium constant and the correct direction favored at equilibrium.

Consider the hypothetical reaction A + 2 B AB₂ at equilibrium.Which is true?

What will happen if the temperature is decreased after equilibrium has been established in the reaction below? 2 C₂H₆(g)+ 7 O₂(g) 4 CO₂(g)+ 6 H₂O(g)+ 2855 kJ

Consider the hypothetical reaction A₂ + B₂ 2 AB When will the forward reaction rate be at a maximum,and when will the reverse reaction rate be at a maximum?