Question 1

Which of the following is true?

Accepted Answer

A)  Reactions with low activation energies are rapid. 
B)  The activation energy for an exothermic reaction is negative. 
C)  both a and b 
D)  neither a nor b 
A)  Reactions with low activation energies are rapid. 
B)  The activation energy for an exothermic reaction is negative. 
C)  both a and b 
D)  neither a nor b

Question 2

Acetic acid is the active ingredient in vinegar. In a solution of acetic acid the following equilibrium is established.   . The equilibrium constant for this reaction is 1.8 × 10-5. What is the equilibrium constant for the following reaction ?

Accepted Answer

A)  1.8 × 10-5 
B)  4.2 × 10-3 
C)  5.6 × 104 
D)  3.1 × 109 
A)  1.8 × 10-5 
B)  4.2 × 10-3 
C)  5.6 × 104 
D)  3.1 × 109

Question 3

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

Accepted Answer

A)  0.099 
B)  0.18 
C)  5.4 
D)  1.0 × 101 
A)  0.099 
B)  0.18 
C)  5.4 
D)  1.0 × 101

Question 4

Which of the following best describes the rates of chemical reaction?

Accepted Answer

A)  Most chemical reactions occur very slowly. 
B)  Most chemical reactions occur at moderate rates. 
C)  Most chemical reactions occur very rapidly. 
D)  Chemical reactions have a wide range of rates, from extremely fast to extremely slow. 
A)  Most chemical reactions occur very slowly. 
B)  Most chemical reactions occur at moderate rates. 
C)  Most chemical reactions occur very rapidly. 
D)  Chemical reactions have a wide range of rates, from extremely fast to extremely slow.

Question 5

If the endothermic reaction   has reached equilibrium, what is the effect of lowering the temperature of the reaction vessel?

Accepted Answer

A)  The reaction will shift left to right. 
B)  The reaction will shift right to left. 
C)  There will be no further reaction. 
D)  What happens depends on the temperature. 
A)  The reaction will shift left to right. 
B)  The reaction will shift right to left. 
C)  There will be no further reaction. 
D)  What happens depends on the temperature.

Question 6

Which of the following will change the numerical value of the equilibrium constant of a particular reaction?

Accepted Answer

A)  increasing the concentration of reactants 
B)  increasing the concentration of products 
C)  increasing the temperature 
D)  all of the above 
A)  increasing the concentration of reactants 
B)  increasing the concentration of products 
C)  increasing the temperature 
D)  all of the above

Question 7

The rate of reaction for the decomposition of hydrogen peroxide to yield water and oxygen is given by the equation: Rate = k[H2O2]. Which of the following is indicated by this equation?

Accepted Answer

A)  The rate of the reaction is unaffected by the concentration of H2O2. 
B)  The rate of the reaction will increase with increasing concentration of H2O2. 
C)  The rate of the reaction will decrease with increasing concentration of H2O2. 
D)  none of these 
A)  The rate of the reaction is unaffected by the concentration of H2O2. 
B)  The rate of the reaction will increase with increasing concentration of H2O2. 
C)  The rate of the reaction will decrease with increasing concentration of H2O2. 
D)  none of these

Question 8

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 insure drug release prior to the drug reaching the stomach 
C)  to insure drug release in the stomach 
D)  to insure drug release in the intestine 
A)  to control time release of the drug in the stomach 
B)  to insure drug release prior to the drug reaching the stomach 
C)  to insure drug release in the stomach 
D)  to insure drug release in the intestine

Question 9

Consider a sample of water in a closed, rigid container. Which of the following would indicate that the reaction   has reached equilibrium?

Accepted Answer

A)  The mass of the container remains constant. 
B)  The pressure in the container remains constant. 
C)  The volume of the container remains constant. 
D)  all of the above 
A)  The mass of the container remains constant. 
B)  The pressure in the container remains constant. 
C)  The volume of the container remains constant. 
D)  all of the above

Question 10

When considering the effect of a catalyst on a system to which Le Chatelier's Principle can be applied, which of the following is true?

Accepted Answer

A)  Addition of a catalyst has absolutely no effect on the reaction. 
B)  Addition of a catalyst speeds up the forward reaction. 
C)  Addition of a catalyst speeds up the reverse reaction. 
D)  Addition of a catalyst speeds up both the forward and reverse reaction by the same amount. 
A)  Addition of a catalyst has absolutely no effect on the reaction. 
B)  Addition of a catalyst speeds up the forward reaction. 
C)  Addition of a catalyst speeds up the reverse reaction. 
D)  Addition of a catalyst speeds up both the forward and reverse reaction by the same amount.

Question 11

In the reaction 2HgO(s) → 2Hg(l) + O2(g) we measure the evolution of gas to determine the rate of reaction. At the beginning of the reaction (at 0 minutes), 0.020 L of O2 is present. After 15 minutes the volume of O2 is 0.35 L. What is the rate of reaction?

Accepted Answer

A)  0.022 L/min 
B)  0.023 L/min 
C)  0.23 L/min 
D)  0.33 L/min 
A)  0.022 L/min 
B)  0.023 L/min 
C)  0.23 L/min 
D)  0.33 L/min

Question 12

Which of the following will change the numerical value of the equilibrium constant of a particular reaction?

Accepted Answer

A)  increasing the concentration of the products 
B)  increasing the temperature 
C)  both a and b 
D)  neither a nor b 
A)  increasing the concentration of the products 
B)  increasing the temperature 
C)  both a and b 
D)  neither a nor b

Question 13

A catalyst speeds up a chemical reaction as a result of which of the following?

Accepted Answer

A)  It increases the number of collisions between reacting molecules. 
B)  It makes the reaction more endothermic. 
C)  It makes the reaction more exothermic. 
D)  none of the above 
A)  It increases the number of collisions between reacting molecules. 
B)  It makes the reaction more endothermic. 
C)  It makes the reaction more exothermic. 
D)  none of the above

Question 14

A particular chemical reaction carried out at 40°C takes 2 hours. Approximately how long will it take to carry out the reaction at 20°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 15

Which of the following will change the numerical value of the equilibrium constant of a particular reaction?

Accepted Answer

A)  increasing the concentration of the reactants 
B)  increasing the concentration of the products 
C)  both a and b 
D)  neither a nor b 
A)  increasing the concentration of the reactants 
B)  increasing the concentration of the products 
C)  both a and b 
D)  neither a nor b

Question 16

Which of the following could be the equilibrium constant for a reaction which does not yield a significant concentration of products?

Accepted Answer

A)  1 × 10-15 
B)  1 × 10-2 
C)  1 × 102 
D)  1 × 1015 
A)  1 × 10-15 
B)  1 × 10-2 
C)  1 × 102 
D)  1 × 1015

Question 17

Which of the following is true of a reaction which has reached equilibrium?

Accepted Answer

A)  The reactants have been completely converted to products. 
B)  The rate of the forward reaction is faster than the rate of the reverse reaction. 
C)  The rate of the forward reaction is equal to the rate of the reverse reaction. 
D)  The rate of the forward reaction is slower than the rate of the reverse reaction. 
A)  The reactants have been completely converted to products. 
B)  The rate of the forward reaction is faster than the rate of the reverse reaction. 
C)  The rate of the forward reaction is equal to the rate of the reverse reaction. 
D)  The rate of the forward reaction is slower than the rate of the reverse reaction.

Question 18

The temperature effect on reaction rate is the result of which of the following?

Accepted Answer

A)  At higher temperatures there are more collisions. 
B)  At higher temperatures a larger fraction of the collisions are effective collisions. 
C)  both a and b 
D)  neither a nor b 
A)  At higher temperatures there are more collisions. 
B)  At higher temperatures a larger fraction of the collisions are effective collisions. 
C)  both a and b 
D)  neither a nor b

Question 19

In a particular chemical reaction 3 bonds are broken and 4 bonds are formed. Based only on this information, which of the following is true?

Accepted Answer

A)  The reaction has a high activation energy. 
B)  The reaction is endothermic. 
C)  the reaction is exothermic. 
D)  We cannot determine which of the above is true. 
A)  The reaction has a high activation energy. 
B)  The reaction is endothermic. 
C)  the reaction is exothermic. 
D)  We cannot determine which of the above is true.

Question 20

When the concentration of a reactant is decreased which of the following is true?

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.

Exam 7: Reaction Rates and Chemical Equilibrium

Which of the following is true?

Acetic acid is the active ingredient in vinegar. In a solution of acetic acid the following equilibrium is established. . The equilibrium constant for this reaction is 1.8 × 10-5. What is the equilibrium constant for the following reaction ?

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

Which of the following best describes the rates of chemical reaction?

If the endothermic reaction has reached equilibrium, what is the effect of lowering the temperature of the reaction vessel?

Which of the following will change the numerical value of the equilibrium constant of a particular reaction?

The rate of reaction for the decomposition of hydrogen peroxide to yield water and oxygen is given by the equation: Rate = k[H2O2]. Which of the following is indicated by this equation?

What is the purpose of the enteric coating of aspirin?

Consider a sample of water in a closed, rigid container. Which of the following would indicate that the reaction has reached equilibrium?

When considering the effect of a catalyst on a system to which Le Chatelier's Principle can be applied, which of the following is true?

In the reaction 2HgO(s) → 2Hg(l) + O2(g) we measure the evolution of gas to determine the rate of reaction. At the beginning of the reaction (at 0 minutes), 0.020 L of O2 is present. After 15 minutes the volume of O2 is 0.35 L. What is the rate of reaction?

Which of the following will change the numerical value of the equilibrium constant of a particular reaction?

A catalyst speeds up a chemical reaction as a result of which of the following?

A particular chemical reaction carried out at 40°C takes 2 hours. Approximately how long will it take to carry out the reaction at 20°C?

Which of the following will change the numerical value of the equilibrium constant of a particular reaction?

Which of the following could be the equilibrium constant for a reaction which does not yield a significant concentration of products?

Which of the following is true of a reaction which has reached equilibrium?

The temperature effect on reaction rate is the result of which of the following?

In a particular chemical reaction 3 bonds are broken and 4 bonds are formed. Based only on this information, which of the following is true?

When the concentration of a reactant is decreased which of the following is true?

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Acetic acid is the active ingredient in vinegar. In a solution of acetic acid the following equilibrium is established. . The equilibrium constant for this reaction is 1.8 × 10^-5. What is the equilibrium constant for the following reaction ?

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

The rate of reaction for the decomposition of hydrogen peroxide to yield water and oxygen is given by the equation: Rate = k[H₂O₂]. Which of the following is indicated by this equation?

In the reaction 2HgO(s) → 2Hg(l) + O₂(g) we measure the evolution of gas to determine the rate of reaction. At the beginning of the reaction (at 0 minutes), 0.020 L of O₂ is present. After 15 minutes the volume of O₂ is 0.35 L. What is the rate of reaction?