Question 1

Which of the following is not true of effective collisions?

Accepted Answer

A)  The number of effective collisions does not affect the reaction rate. 
B)  The number of effective collisions increases as the temperature increases. 
C)  The number of effective collisions is dependent on the orientation of the molecules. 
D)  The number of effective collisions is dependent on the overall frequency of collisions. 
A)  The number of effective collisions does not affect the reaction rate. 
B)  The number of effective collisions increases as the temperature increases. 
C)  The number of effective collisions is dependent on the orientation of the molecules. 
D)  The number of effective collisions is dependent on the overall frequency of collisions.

Question 2

A particular chemical reaction carried out at 30°C takes 4 hours. Approximately how long will it take to carry out the reaction at 60°C?

Accepted Answer

A)  0.5 hour 
B)  1 hour 
C)  4 hours 
D)  8 hours 
A)  0.5 hour 
B)  1 hour 
C)  4 hours 
D)  8 hours

Question 3

Which of the following are generally included when writing an equilibrium constant expression?

Accepted Answer

A)  masses of pure liquids 
B)  masses of pure solids 
C)  concentrations of catalysts in solutions 
D)  concentrations of pure gases in solutions 
A)  masses of pure liquids 
B)  masses of pure solids 
C)  concentrations of catalysts in solutions 
D)  concentrations of pure gases in solutions

Question 4

When considering the effect of a catalyst on a system that has not reached equilibrium, which of the following is true?

Accepted Answer

A)  The addition of a catalyst has absolutely no effect on the reaction. 
B)  The addition of a catalyst speeds up the forward reaction. 
C)  The addition of a catalyst speeds up the reverse reaction. 
D)  The addition of a catalyst causes the system to reach equilibrium faster. 
A)  The addition of a catalyst has absolutely no effect on the reaction. 
B)  The addition of a catalyst speeds up the forward reaction. 
C)  The addition of a catalyst speeds up the reverse reaction. 
D)  The addition of a catalyst causes the system to reach equilibrium faster.

Question 5

Solid sodium chloride and solid silver nitrate react to form sodium nitrate and silver chloride. The reaction is extremely slow. However, if the sodium chloride and silver nitrate are first dissolved in water and the two solutions are mixed, the reaction occurs very rapidly. Which of the following explains the difference in reaction rates?

Accepted Answer

A)  Ions in solution have high mobility, and ions of opposite charges are attracted to each other. 
B)  The concentration of ions in solution is greater than the concentration of ions in the solid. 
C)  Sodium chloride solution does not react with solid silver nitrate. 
D)  Silver nitrate solution does not react with solid sodium chloride. 
A)  Ions in solution have high mobility, and ions of opposite charges are attracted to each other. 
B)  The concentration of ions in solution is greater than the concentration of ions in the solid. 
C)  Sodium chloride solution does not react with solid silver nitrate. 
D)  Silver nitrate solution does not react with solid sodium chloride.

Question 6

In writing the equilibrium constant expression, we use square brackets. What does the notation [A] represent?

Accepted Answer

A)  the mass of A 
B)  the number of moles of A 
C)  the molar concentration of A 
D)  the valency of A 
A)  the mass of A 
B)  the number of moles of A 
C)  the molar concentration of A 
D)  the valency of A

Question 7

The reaction H2O2(l) + 3I-(aq) + 2 H+(aq) → I3-(aq) + 2H2O(aq) occurs very rapidly. Based on this observation alone, what can we say about this reaction?

Accepted Answer

A)  The reaction probably occurs as a single fast step. 
B)  The reaction probably occurs as a series of steps, each of which is fast. 
C)  The reaction is endothermic. 
D)  The reaction is exothermic. 
A)  The reaction probably occurs as a single fast step. 
B)  The reaction probably occurs as a series of steps, each of which is fast. 
C)  The reaction is endothermic. 
D)  The reaction is exothermic.

Question 8

Which of the following is not true of the catalyst of a reaction?

Accepted Answer

A)  It causes a system to reach equilibrium slower than if the reaction were uncatalyzed. 
B)  The quantity of the catalyst remains the same before and after the reaction. 
C)  It has no effect on the equilibrium constant for the reaction. 
D)  Any of the these, as it depends on the reaction involved. 
A)  It causes a system to reach equilibrium slower than if the reaction were uncatalyzed. 
B)  The quantity of the catalyst remains the same before and after the reaction. 
C)  It has no effect on the equilibrium constant for the reaction. 
D)  Any of the these, as it depends on the reaction involved.

Question 9

Consider the following graph.   The graph is based on data collected from the following reaction.   Which curve on the graph represents the change in concentration of CH3COOC2H5 for the forward reaction?

Accepted Answer

A)  A 
B)  B 
C)  It is not possible to show the production of water. 
A)  A 
B)  B 
C)  It is not possible to show the production of water.

Question 10

The term "heterogeneous catalyst" means which of the following?

Accepted Answer

A)  a catalyst that does not have uniform composition 
B)  a catalyst that is of a different phase from the reactants 
C)  a catalyst that gets consumed completely in the course of the reaction 
D)  a catalyst that changes its composition in the course of the reaction 
A)  a catalyst that does not have uniform composition 
B)  a catalyst that is of a different phase from the reactants 
C)  a catalyst that gets consumed completely in the course of the reaction 
D)  a catalyst that changes its composition in the course of the reaction

Question 11

How does the rate of reaction change as the concentration of the product increases over the course of a reaction?

Accepted Answer

A)  The rate of reaction always decreases. 
B)  The rate of reaction usually decreases. 
C)  The rate of reaction always increases. 
D)  The rate of reaction usually increases. 
A)  The rate of reaction always decreases. 
B)  The rate of reaction usually decreases. 
C)  The rate of reaction always increases. 
D)  The rate of reaction usually increases.

Question 12

For the reaction   equilibrium is established at 25°C when [NOCl] = 2.6 M, [NO] = 0.34 M, and [Cl2] = 1.4 M. What is the equilibrium constant for this reaction?

Accepted Answer

A)  0.099 
B)  0.18 
C)  5.4 
D)  42.2 
A)  0.099 
B)  0.18 
C)  5.4 
D)  42.2

Question 13

Suppose the equilibrium constant for the chemical reaction is 3.3 × 107.   ​ What is the equilibrium constant for the following reaction?

Accepted Answer

A)  1.99 × 10-5 
B)  4.3 × 10-8 
C)  3.3 × 107 
D)  1.09 × 1015 
A)  1.99 × 10-5 
B)  4.3 × 10-8 
C)  3.3 × 107 
D)  1.09 × 1015

Question 14

If the exothermic reaction   has reached equilibrium, what is the effect of reducing the temperature of the reaction vessel?

Accepted Answer

A)  The reaction will shift from the left to the right. 
B)  The reaction will shift from the right to the left. 
C)  There will be no effect. 
D)  Whether the reaction will shift to the left or the right depends on the initial temperature. 
A)  The reaction will shift from the left to the right. 
B)  The reaction will shift from the right to the left. 
C)  There will be no effect. 
D)  Whether the reaction will shift to the left or the right depends on the initial temperature.

Question 15

For the exothermic reaction   making which of the following changes will ensure that the reaction will not shift either to the left or to the right?

Accepted Answer

A)  adding H2 and N2 and removing NH3 
B)  adding H2 and lowering the temperature 
C)  adding H2 and raising the temperature 
D)  adding H2 and decreasing the volume of the beaker 
A)  adding H2 and N2 and removing NH3 
B)  adding H2 and lowering the temperature 
C)  adding H2 and raising the temperature 
D)  adding H2 and decreasing the volume of the beaker

Question 16

Which of the following statements is true of the reaction A + B → 2C?

Accepted Answer

A)  B is consumed at the same rate that A is consumed. 
B)  C is produced at the same rate A is consumed. 
C)  C is produced at the same rate B is consumed. 
D)  B is produced at the same rate A is consumed. 
A)  B is consumed at the same rate that A is consumed. 
B)  C is produced at the same rate A is consumed. 
C)  C is produced at the same rate B is consumed. 
D)  B is produced at the same rate A is consumed.

Question 17

Which of the following is true of a reversible reaction?

Accepted Answer

A)  Equilibrium can only be reached by mixing the starting materials. 
B)  Equilibrium can only be reached by mixing the products. 
C)  Equilibrium can only be reached by mixing specific amounts of starting materials and products. 
D)  Equilibrium will always be reached as time progresses. 
A)  Equilibrium can only be reached by mixing the starting materials. 
B)  Equilibrium can only be reached by mixing the products. 
C)  Equilibrium can only be reached by mixing specific amounts of starting materials and products. 
D)  Equilibrium will always be reached as time progresses.

Question 18

Consider the following graph.   The graph is based on data collected from the following reaction.   At what point on the graph does the rate of the forward reaction equal the rate of the reverse reaction?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  The point of intersection of A and B 
A)  1 
B)  2 
C)  3 
D)  The point of intersection of A and B

Question 19

A particular reaction has an equilibrium constant of 1 × 1020. Which of the following best describes the relationship between the equilibrium constant and the reaction rate?

Accepted Answer

A)  Because the equilibrium constant is large, the reaction proceeds rapidly. 
B)  There is no relationship between the size of the equilibrium constant and the rate of the reaction. 
C)  Because the equilibrium constant is large, the reaction proceeds rapidly, and there is no relationship between the size of the equilibrium constant and the rate of the reaction. 
D)  None of these. 
A)  Because the equilibrium constant is large, the reaction proceeds rapidly. 
B)  There is no relationship between the size of the equilibrium constant and the rate of the reaction. 
C)  Because the equilibrium constant is large, the reaction proceeds rapidly, and there is no relationship between the size of the equilibrium constant and the rate of the reaction. 
D)  None of these.

Question 20

What is the purpose of the enteric coating of aspirin?

Accepted Answer

A)  to control time release of the drug in the stomach 
B)  to ensure drug release before the drug reaches the stomach 
C)  to ensure drug release in the stomach 
D)  to ensure drug release in the intestine 
A)  to control time release of the drug in the stomach 
B)  to ensure drug release before the drug reaches the stomach 
C)  to ensure drug release in the stomach 
D)  to ensure drug release in the intestine

Exam 7: Reaction Rates and Chemical Equilibrium

Which of the following is not true of effective collisions?

A particular chemical reaction carried out at 30°C takes 4 hours. Approximately how long will it take to carry out the reaction at 60°C?

Which of the following are generally included when writing an equilibrium constant expression?

When considering the effect of a catalyst on a system that has not reached equilibrium, which of the following is true?

In writing the equilibrium constant expression, we use square brackets. What does the notation [A] represent?

The reaction H2O2(l) + 3I-(aq) + 2 H+(aq) → I3-(aq) + 2H2O(aq) occurs very rapidly. Based on this observation alone, what can we say about this reaction?

Which of the following is not true of the catalyst of a reaction?

Consider the following graph. The graph is based on data collected from the following reaction. Which curve on the graph represents the change in concentration of CH3COOC2H5 for the forward reaction?

The term "heterogeneous catalyst" means which of the following?

How does the rate of reaction change as the concentration of the product increases over the course of a reaction?

For the reaction equilibrium is established at 25°C when [NOCl] = 2.6 M, [NO] = 0.34 M, and [Cl2] = 1.4 M. What is the equilibrium constant for this reaction?

Suppose the equilibrium constant for the chemical reaction is 3.3 × 107. ​ What is the equilibrium constant for the following reaction?

If the exothermic reaction has reached equilibrium, what is the effect of reducing the temperature of the reaction vessel?

For the exothermic reaction making which of the following changes will ensure that the reaction will not shift either to the left or to the right?

Which of the following statements is true of the reaction A + B → 2C?

Which of the following is true of a reversible reaction?

Consider the following graph. The graph is based on data collected from the following reaction. At what point on the graph does the rate of the forward reaction equal the rate of the reverse reaction?

A particular reaction has an equilibrium constant of 1 × 1020. Which of the following best describes the relationship between the equilibrium constant and the reaction rate?

What is the purpose of the enteric coating of aspirin?

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The reaction H₂O₂(l) + 3I^-(aq) + 2 H⁺(aq) → I₃^-(aq) + 2H₂O(aq) occurs very rapidly. Based on this observation alone, what can we say about this reaction?

Consider the following graph. The graph is based on data collected from the following reaction. Which curve on the graph represents the change in concentration of CH₃COOC₂H₅ for the forward reaction?

For the reaction equilibrium is established at 25°C when [NOCl] = 2.6 M, [NO] = 0.34 M, and [Cl₂] = 1.4 M. What is the equilibrium constant for this reaction?

Suppose the equilibrium constant for the chemical reaction is 3.3 × 10⁷. What is the equilibrium constant for the following reaction?

A particular reaction has an equilibrium constant of 1 × 10²⁰. Which of the following best describes the relationship between the equilibrium constant and the reaction rate?