Question 1

Drug manufacturers use which of the following when making time release drugs?

Accepted Answer

A)  control of the thickness of a drug coating 
B)  control of the size 
C)  both a and b 
D)  neither a nor b 
A)  control of the thickness of a drug coating 
B)  control of the size 
C)  both a and b 
D)  neither a nor b

Question 2

In writing the equilibrium constant expression we use square brackets. The notation [A] means which of the following?

Accepted Answer

A)  the mass of A 
B)  the number of moles of A 
C)  the molar concentration of A 
D)  none of the above 
A)  the mass of A 
B)  the number of moles of A 
C)  the molar concentration of A 
D)  none of the above

Question 3

If a particular reactant is involved in the slowest step of a multi-step reaction what will be the effect of increasing its concentration?

Accepted Answer

A)  The reaction rate will decrease. 
B)  The reaction rate will increase. 
C)  The reaction rate will be unaffected. 
A)  The reaction rate will decrease. 
B)  The reaction rate will increase. 
C)  The reaction rate will be unaffected.

Question 4

For the reaction   which of the following is the equilibrium constant expression?

Accepted Answer

A)  K = [H2][O2]/[H2O] 
B)  K = [H2O]/[H2][O2] 
C)  K = [H2O]2/[H2]2[O2] 
D)  K = [H2]2[O2]/[H2O]2 
A)  K = [H2][O2]/[H2O] 
B)  K = [H2O]/[H2][O2] 
C)  K = [H2O]2/[H2]2[O2] 
D)  K = [H2]2[O2]/[H2O]2

Question 5

Which of the following describes the effect of raising the temperature of an exothermic reaction which has not yet reached equilibrium?

Accepted Answer

A)  The rate of reaction slows and less product is produced. 
B)  The rate of reaction slows, but more product is produced. 
C)  The rate of reaction speeds up, but less product is produced. 
D)  The rate of reaction speeds up and more product is produced. 
A)  The rate of reaction slows and less product is produced. 
B)  The rate of reaction slows, but more product is produced. 
C)  The rate of reaction speeds up, but less product is produced. 
D)  The rate of reaction speeds up and more product is produced.

Question 6

Consider a sample of water in a closed container. When the reaction   has reached equilibrium what can we say about any specific water molecule?

Accepted Answer

A)  If it was present in the liquid it will always remain in the liquid phase. 
B)  If it was present in the vapor it will always remain in the vapor phase. 
C)  It will sometimes be in the liquid phase and sometimes in the vapor phase. 
D)  Both a and b are true. 
A)  If it was present in the liquid it will always remain in the liquid phase. 
B)  If it was present in the vapor it will always remain in the vapor phase. 
C)  It will sometimes be in the liquid phase and sometimes in the vapor phase. 
D)  Both a and b are true.

Question 7

Which of the following is true of the rates of most chemical reactions?

Accepted Answer

A)  The initial rate is cannot be measured. 
B)  The initial rate is faster than the rate later in time. 
C)  The initial rate is the same as the rate later in time. 
D)  The initial rate is slower than the rate later in time. 
A)  The initial rate is cannot be measured. 
B)  The initial rate is faster than the rate later in time. 
C)  The initial rate is the same as the rate later in time. 
D)  The initial rate is slower than the rate later in time.

Question 8

For the reaction A + B → 2 C, which of the following statements is true?

Accepted Answer

A)  B is consumed at the same rate that A is consumed. 
B)  C is produced at twice the rate A is consumed. 
C)  both a and b 
D)  neither a nor b 
A)  B is consumed at the same rate that A is consumed. 
B)  C is produced at twice the rate A is consumed. 
C)  both a and b 
D)  neither a nor b

Question 9

If a reaction occurs very rapidly, even at a relatively low temperature, which of the following is probably true?

Accepted Answer

A)  The reaction is endothermic. 
B)  The reaction is exothermic. 
C)  The reaction has a low activation energy. 
D)  The reaction occurs as a single step. 
A)  The reaction is endothermic. 
B)  The reaction is exothermic. 
C)  The reaction has a low activation energy. 
D)  The reaction occurs as a single step.

Question 10

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)  Provided one is prepared to wait long enough, equilibrium will always be reached if any combination of starting materials and products are mixed. 
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)  Provided one is prepared to wait long enough, equilibrium will always be reached if any combination of starting materials and products are mixed.

Question 11

What is the effect of adding H2O(l) to a container in which the reaction has reached equilibrium?

Accepted Answer

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

Question 12

Which of the following is true of all multi-step reactions?

Accepted Answer

A)  They involve more than two reactant molecules. 
B)  They are endothermic. 
C)  they are exothermic. 
D)  The rate of reaction is determined by the slowest step. 
A)  They involve more than two reactant molecules. 
B)  They are endothermic. 
C)  they are exothermic. 
D)  The rate of reaction is determined by the slowest step.

Question 13

If a chemist wishes to carry out a reaction in which one reactant is a solid and one is a liquid, which of the following will be most effective in speeding up the reaction?

Accepted Answer

A)  adding more liquid reactant 
B)  grinding the solid to a form a powder 
C)  placing a larger crystal of the solid in the same volume of liquid reactant 
D)  All of the above will be equally effective. 
A)  adding more liquid reactant 
B)  grinding the solid to a form a powder 
C)  placing a larger crystal of the solid in the same volume of liquid reactant 
D)  All of the above will be equally effective.

Question 14

Consider the following energy diagram for a reaction.  
-Which letter represents the activation energy for the reaction?

Accepted Answer

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

Question 15

For which of the following reactions is it important that the species collide with the correct orientation?

Accepted Answer

A)  2 NO(g) + O2(g) → 2 NO2(g) 
B)  HCl(g) + H2O(l) → H3O+(aq) + Cl-(aq) 
C)  both of them 
D)  neither of them 
A)  2 NO(g) + O2(g) → 2 NO2(g) 
B)  HCl(g) + H2O(l) → H3O+(aq) + Cl-(aq) 
C)  both of them 
D)  neither of them

Question 16

Which of the following is the best definition of a catalyst?

Accepted Answer

A)  A catalyst is a material which speeds up the rate of a chemical reaction. 
B)  A catalyst is a material which speeds up the rate of a chemical reaction without participating in the reaction. 
C)  A catalyst is a material which speeds up the rate of a chemical reaction without being consumed during the reaction. 
D)  All of the above are equally good definitions. 
A)  A catalyst is a material which speeds up the rate of a chemical reaction. 
B)  A catalyst is a material which speeds up the rate of a chemical reaction without participating in the reaction. 
C)  A catalyst is a material which speeds up the rate of a chemical reaction without being consumed during the reaction. 
D)  All of the above are equally good definitions.

Question 17

Which of the following could be the equilibrium constant for a reaction which proceeds very far in the direction of the 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 18

For the reaction   at 472°C equilibrium is established when [H2] =0.0200M, [N2] = 0.0100M and [NH3] = 5.37 × 10-8M. What is the equilibrium constant for the reverse reaction?

Accepted Answer

A)  3.72 × 103 
B)  2.77 × 107 
C)  1.39 × 109 
D)  6.94 × 1010 
A)  3.72 × 103 
B)  2.77 × 107 
C)  1.39 × 109 
D)  6.94 × 1010

Question 19

Which of the following is generally not included when writing an equilibrium constant expression?

Accepted Answer

A)  liquids 
B)  solids 
C)  both a and b 
D)  neither a nor b 
A)  liquids 
B)  solids 
C)  both a and b 
D)  neither a nor b

Question 20

Given that the reaction 2 H2(g) + O2(g) → 2 H2O(g) is exothermic, which of the following is true of the reaction 2 H2O(g) → 2 H2(g) + O2(g) ?

Accepted Answer

A)  Its activation energy is lower than that of 2 H2(g) + O2(g ) → 2 H2O(g). 
B)  Its activation energy is the same as that of 2 H2(g) + O2(g ) → 2 H2O(g). 
C)  Its activation energy is higher than that of 2 H2(g) + O2(g ) → 2 H2O(g). 
D)  There is no relationship between its activation energy and that of 2 H2(g) + O2(g ) → 2 H2O(g). 
A)  Its activation energy is lower than that of 2 H2(g) + O2(g ) → 2 H2O(g). 
B)  Its activation energy is the same as that of 2 H2(g) + O2(g ) → 2 H2O(g). 
C)  Its activation energy is higher than that of 2 H2(g) + O2(g ) → 2 H2O(g). 
D)  There is no relationship between its activation energy and that of 2 H2(g) + O2(g ) → 2 H2O(g).

Exam 7: Reaction Rates and Chemical Equilibrium

Drug manufacturers use which of the following when making time release drugs?

In writing the equilibrium constant expression we use square brackets. The notation [A] means which of the following?

If a particular reactant is involved in the slowest step of a multi-step reaction what will be the effect of increasing its concentration?

For the reaction which of the following is the equilibrium constant expression?

Which of the following describes the effect of raising the temperature of an exothermic reaction which has not yet reached equilibrium?

Consider a sample of water in a closed container. When the reaction has reached equilibrium what can we say about any specific water molecule?

Which of the following is true of the rates of most chemical reactions?

For the reaction A + B → 2 C, which of the following statements is true?

If a reaction occurs very rapidly, even at a relatively low temperature, which of the following is probably true?

Which of the following is true of a reversible reaction?

What is the effect of adding H2O(l) to a container in which the reaction has reached equilibrium?

Which of the following is true of all multi-step reactions?

If a chemist wishes to carry out a reaction in which one reactant is a solid and one is a liquid, which of the following will be most effective in speeding up the reaction?

Consider the following energy diagram for a reaction. -Which letter represents the activation energy for the reaction?

For which of the following reactions is it important that the species collide with the correct orientation?

Which of the following is the best definition of a catalyst?

Which of the following could be the equilibrium constant for a reaction which proceeds very far in the direction of the products?

For the reaction at 472°C equilibrium is established when [H2] =0.0200M, [N2] = 0.0100M and [NH3] = 5.37 × 10-8M. What is the equilibrium constant for the reverse reaction?

Which of the following is generally not included when writing an equilibrium constant expression?

Given that the reaction 2 H2(g) + O2(g) → 2 H2O(g) is exothermic, which of the following is true of the reaction 2 H2O(g) → 2 H2(g) + O2(g) ?

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What is the effect of adding H₂O(l) to a container in which the reaction has reached equilibrium?

For the reaction at 472°C equilibrium is established when [H₂] =0.0200M, [N₂] = 0.0100M and [NH₃] = 5.37 × 10^-8M. What is the equilibrium constant for the reverse reaction?

Given that the reaction 2 H₂(g) + O₂(g) → 2 H₂O(g) is exothermic, which of the following is true of the reaction 2 H₂O(g) → 2 H₂(g) + O₂(g) ?