Question 1

In an energy diagram for a chemical reaction what species represents the highest energy?

Accepted Answer

A)  the catalyst 
B)  the products 
C)  the reactants 
D)  the transition state 
A)  the catalyst 
B)  the products 
C)  the reactants 
D)  the transition state

Question 2

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

Accepted Answer

A)  A catalyst which does not have uniform composition. 
B)  A catalyst which is of a different phase from that of the reaction it catalyzes. 
C)  both a and b 
D)  neither a nor b 
A)  A catalyst which does not have uniform composition. 
B)  A catalyst which is of a different phase from that of the reaction it catalyzes. 
C)  both a and b 
D)  neither a nor b

Question 3

For the exothermic reaction   which of the following changes could be carried out in such a way as to not cause the reaction to shift either to the left or to the right?

Accepted Answer

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

Question 4

The reaction H2O2(l) + 3 I-(aq) + 2 H+(aq) → I3-(aq) + 2 H2O(aq) occurs very rapidly. Based on this observation only, 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 5

For the exothermic reaction   which of the following changes could be carried out in such a way as to not cause the reaction to shift either to the left or to the right?

Accepted Answer

A)  raising the temperature and adding NH3 
B)  lowering the temperature and removing NH3 
C)  both 
A)  and b 
D)  neither a nor b 
A)  raising the temperature and adding NH3 
B)  lowering the temperature and removing NH3 
C)  both 
A)  and b 
D)  neither a nor b

Question 6

For the reaction A + B → 2 C, which of the following best describes how we can measure the reaction rate?

Accepted Answer

A)  The rate can be measured by measuring how fast A is consumed. 
B)  The rate can be measured by measuring how fast C is produced. 
C)  Either of the above procedures can be used. 
D)  Neither of the above procedures can be used. 
A)  The rate can be measured by measuring how fast A is consumed. 
B)  The rate can be measured by measuring how fast C is produced. 
C)  Either of the above procedures can be used. 
D)  Neither of the above procedures can be used.

Question 7

For the reaction   at 25°C equilibrium is established 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)  4.22 × 101 
A)  0.099 
B)  0.18 
C)  5.4 
D)  4.22 × 101

Question 8

What is the effect of increasing the temperature at which a reaction is carried out?

Accepted Answer

A)  In all cases the rate of reaction decreases. 
B)  In virtually all cases the rate of reaction decreases. 
C)  In all cases the rate of reaction increases. 
D)  In virtually all cases the rate of reaction increases. 
A)  In all cases the rate of reaction decreases. 
B)  In virtually all cases the rate of reaction decreases. 
C)  In all cases the rate of reaction increases. 
D)  In virtually all cases the rate of reaction increases.

Question 9

Which of the following is true?

Accepted Answer

A)  Decreasing the activation energy decreases the reaction rate. 
B)  Decreasing the activation energy increases the reaction rate. 
C)  The activation energy of an exothermic reaction is negative. 
D)  There is no relationship between activation energy and reaction rate. 
A)  Decreasing the activation energy decreases the reaction rate. 
B)  Decreasing the activation energy increases the reaction rate. 
C)  The activation energy of an exothermic reaction is negative. 
D)  There is no relationship between activation energy and reaction rate.

Question 10

A particular chemical reaction carried out at 20°C takes 2 hours. Approximately how long will it take to carry out the reaction at 40°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 11

Which of the following is the study of the rates of chemical reactions?

Accepted Answer

A)  kinetics 
B)  stoichiometry 
C)  thermodynamics 
D)  none of these 
A)  kinetics 
B)  stoichiometry 
C)  thermodynamics 
D)  none of these

Question 12

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)  None of the above will have a significant effect on the rate of reaction 
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)  None of the above will have a significant effect on the rate of reaction

Question 13

Consider a reaction such as A2(g) + B2 (g) → 2AB(g). What can we say about the mechanism of the reaction?

Accepted Answer

A)  If the reaction is fast it occurs in a single step. 
B)  If the reaction is fast it occurs in multiple steps. 
C)  If the reaction is slow it occurs in multiple steps. 
D)  We must examine each case individually. 
A)  If the reaction is fast it occurs in a single step. 
B)  If the reaction is fast it occurs in multiple steps. 
C)  If the reaction is slow it occurs in multiple steps. 
D)  We must examine each case individually.

Question 14

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)  It provides an alternative reaction pathway. 
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)  It provides an alternative reaction pathway.

Question 15

In a particular chemical reaction 2 bonds are broken and no 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 16

Which of the following does not result from increasing the temperature of a reaction?

Accepted Answer

A)  A larger fraction of the collisions are effective collisions. 
B)  The concentrations of the reactants are increased. 
C)  There are more collisions. 
D)  None, all of the above are a result of increasing the temperature. 
A)  A larger fraction of the collisions are effective collisions. 
B)  The concentrations of the reactants are increased. 
C)  There are more collisions. 
D)  None, all of the above are a result of increasing the temperature.

Question 17

Le Châtelier's Principle applies to which of the following systems?

Accepted Answer

A)  a system in which the reaction is moving left to right 
B)  a system in which the reaction is moving right to left 
C)  a system which has reached equilibrium 
D)  all of the above 
A)  a system in which the reaction is moving left to right 
B)  a system in which the reaction is moving right to left 
C)  a system which has reached equilibrium 
D)  all of the above

Question 18

Which of the following is true of fevers?

Accepted Answer

A)  An increase in body temperature never has beneficial effects. 
B)  A 1°C increase in temperature can be protective. 
C)  A 3°C increase in temperature is invariably fatal. 
D)  None of the above is true. 
A)  An increase in body temperature never has beneficial effects. 
B)  A 1°C increase in temperature can be protective. 
C)  A 3°C increase in temperature is invariably fatal. 
D)  None of the above is true.

Question 19

Given that the reaction N2(g) + 2 O2(g) → 2 NO2(g) is endothermic, which of the following is true of the reaction 2 NO2(g) → 2 N2(g) + 2 O2(g) ?

Accepted Answer

A)  Its activation energy is lower than that of N2(g) + 2 O2(g) → 2 NO2(g). 
B)  Its activation energy is the same as that of N2(g) + 2 O2(g) → 2 NO2(g). 
C)  Its activation energy is higher than that of N2(g) + 2 O2(g) → 2 NO2(g). 
D)  There is no relationship between its activation energy and that of N2(g) + 2 O2(g) → 2 NO2(g). 
A)  Its activation energy is lower than that of N2(g) + 2 O2(g) → 2 NO2(g). 
B)  Its activation energy is the same as that of N2(g) + 2 O2(g) → 2 NO2(g). 
C)  Its activation energy is higher than that of N2(g) + 2 O2(g) → 2 NO2(g). 
D)  There is no relationship between its activation energy and that of N2(g) + 2 O2(g) → 2 NO2(g).

Question 20

Consider the following energy diagram for a reaction.  
-Which of the following correctly represents this reaction?

Accepted Answer

A)  The energy of the products is less than that of the reactants so the reaction is endothermic. 
B)  The energy of the products is greater than that of the reactants so the reaction is endothermic. 
C)  The energy of the products is less than that of the reactants so the reaction is exothermic. 
D)  The energy of the products is greater than that of the reactants so the reaction is exothermic. 
A)  The energy of the products is less than that of the reactants so the reaction is endothermic. 
B)  The energy of the products is greater than that of the reactants so the reaction is endothermic. 
C)  The energy of the products is less than that of the reactants so the reaction is exothermic. 
D)  The energy of the products is greater than that of the reactants so the reaction is exothermic.

Exam 7: Reaction Rates and Chemical Equilibrium

In an energy diagram for a chemical reaction what species represents the highest energy?

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

For the exothermic reaction which of the following changes could be carried out in such a way as to not cause the reaction to shift either to the left or to the right?

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

For the exothermic reaction which of the following changes could be carried out in such a way as to not cause the reaction to shift either to the left or to the right?

For the reaction A + B → 2 C, which of the following best describes how we can measure the reaction rate?

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

What is the effect of increasing the temperature at which a reaction is carried out?

Which of the following is true?

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

Which of the following is the study of the rates of chemical 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 a reaction such as A2(g) + B2 (g) → 2AB(g). What can we say about the mechanism of the reaction?

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

In a particular chemical reaction 2 bonds are broken and no bonds are formed. Based only on this information, which of the following is true?

Which of the following does not result from increasing the temperature of a reaction?

Le Châtelier's Principle applies to which of the following systems?

Which of the following is true of fevers?

Given that the reaction N2(g) + 2 O2(g) → 2 NO2(g) is endothermic, which of the following is true of the reaction 2 NO2(g) → 2 N2(g) + 2 O2(g) ?

Consider the following energy diagram for a reaction. -Which of the following correctly represents this reaction?

Matter, Energy, and Measurement

Atoms

Chemical Bonds

Chemical Reactions

Gases, Liquids, and Solids

Solutions and Colloids

Acids and Bases

Nuclear Chemistry

Organic Chemistry

Alkanes

Alkenes and Alkynes

Benzene and Its Derivatives

Alcohols, Ethers, and Thiols

Chirality: the Handedness of Molecules

Amines

Aldehydes and Ketones

Carboxylic Acids

Carboxylic Anhydrides, Esters, and Amides

Carbohydrates

Lipids

Proteins

Enzymes

Chemical Communications: Neurotransmitters and Hormones

Nucleotides, Nucleic Acids, and Heredity

Gene Expression and Protein Synthesis

Bioenergetics: How the Body Converts Food to Energy

Specific Catabolic Pathways: Carbohydrate, Lipid, and Protein Metabolism

Biosynthetic Pathways

Nutrition

Immunochemistry

Body Fluids

Filters

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

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

Consider a reaction such as A₂(g) + B₂ (g) → 2AB(g). What can we say about the mechanism of the reaction?

Given that the reaction N₂(g) + 2 O₂(g) → 2 NO₂(g) is endothermic, which of the following is true of the reaction 2 NO₂(g) → 2 N₂(g) + 2 O₂(g) ?