Question 1

If a particular reactant is involved in the slowest step of a multistep reaction, then 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 2

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)  raising the temperature and adding NH3 
B)  lowering the temperature and removing NH3 
C)  raising the temperature and adding NH3 and lowering the temperature and removing NH3 
D)  none of these 
A)  raising the temperature and adding NH3 
B)  lowering the temperature and removing NH3 
C)  raising the temperature and adding NH3 and lowering the temperature and removing NH3 
D)  none of these

Question 3

The rate of reaction for the decomposition of hydrogen peroxide to yield water and oxygen is represented by the following 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 O2. 
B)  The rate of the reaction will increase with the increasing concentration of H2O2. 
C)  The rate of the reaction will decrease with the increasing concentration of O2. 
D)  None of these are indicated by the equation. 
A)  The rate of the reaction is unaffected by the concentration of O2. 
B)  The rate of the reaction will increase with the increasing concentration of H2O2. 
C)  The rate of the reaction will decrease with the increasing concentration of O2. 
D)  None of these are indicated by the equation.

Question 4

What is the effect of decreasing 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 5

In a particular chemical reaction, two bonds are broken and no bonds are formed. Based on this information alone, 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 statements 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 statements is true.

Question 6

Consider the following graph.   The graph is based on data collected from the following reaction.   If Curve B presently represents C2H5OH, how would the graph change if this line represented CH3COOH?

Accepted Answer

A)  The slope of the line would greater. 
B)  The slope of the line would be less. 
C)  The line would be the same. 
D)  This condition cannot be predicted. 
A)  The slope of the line would greater. 
B)  The slope of the line would be less. 
C)  The line would be the same. 
D)  This condition cannot be predicted.

Question 7

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

Accepted Answer

A)  The reaction is endothermic. 
B)  The reaction is exothermic. 
C)  The reaction has a low activation energy. 
D)  The reaction must be a single-step reaction. 
A)  The reaction is endothermic. 
B)  The reaction is exothermic. 
C)  The reaction has a low activation energy. 
D)  The reaction must be a single-step reaction.

Question 8

Given that the reaction 2Na2O (s) → 4Na(s) + 2O2(g) is endothermic, which of the following is true of the reaction 4Na(s) + 2O2(g) → 2Na2O(s)?

Accepted Answer

A)  Its activation energy is lower than that of 2Na2O(s) → 4Na(s) + 2O2(g). 
B)  Its activation energy is the same as that of 2Na2O(s) → 4Na(s) + 2O2(g). 
C)  Its activation energy is higher than that of 2Na2O(s) → 4Na(s) + 2O2(g). 
D)  There is no relationship between its activation energy and that of 2Na2O(s) → 4Na(s) + 2O2(g). 
A)  Its activation energy is lower than that of 2Na2O(s) → 4Na(s) + 2O2(g). 
B)  Its activation energy is the same as that of 2Na2O(s) → 4Na(s) + 2O2(g). 
C)  Its activation energy is higher than that of 2Na2O(s) → 4Na(s) + 2O2(g). 
D)  There is no relationship between its activation energy and that of 2Na2O(s) → 4Na(s) + 2O2(g).

Question 9

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

Accepted Answer

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

Question 10

How does a decrease in temperature affect an endothermic reaction that has not reached equilibrium?

Accepted Answer

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

Question 11

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 12

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)  At higher temperatures, there are more collisions and a larger fraction of the collisions are effective collisions. 
D)  None of these. 
A)  At higher temperatures, there are more collisions. 
B)  At higher temperatures, a larger fraction of the collisions are effective collisions. 
C)  At higher temperatures, there are more collisions and a larger fraction of the collisions are effective collisions. 
D)  None of these.

Question 13

Which of the following is an example of an equilibrium situation?

Accepted Answer

A)  an unsaturated solution 
B)  a saturated solution 
C)  a supersaturated solution 
D)  all of these 
A)  an unsaturated solution 
B)  a saturated solution 
C)  a supersaturated solution 
D)  all of these

Question 14

Which of the following symbols is used to denote a reversible reaction?

Accepted Answer

A)  → 
B)  ← 
C)  ⇌ 
D)  ↔ 
A)  → 
B)  ← 
C)  ⇌ 
D)  ↔

Question 15

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 1.5 × 10-5. What is the equilibrium constant for the following reaction?

Accepted Answer

A)  1.8 × 10-5 
B)  4.2 × 10-3 
C)  6.6 × 104 
D)  3.1 × 109 
A)  1.8 × 10-5 
B)  4.2 × 10-3 
C)  6.6 × 104 
D)  3.1 × 109

Question 16

For the reaction   equilibrium is established at 472°C when [H2] =0.0400 M, [N2] = 0.0200 M, and [NH3] = 1.074 × 10-7M. What is the equilibrium constant for this reaction?

Accepted Answer

A)  4.69 × 10-4 
B)  9.012 × 10-9 
C)  6.21 × 10-10 
D)  7.41 × 10-11 
A)  4.69 × 10-4 
B)  9.012 × 10-9 
C)  6.21 × 10-10 
D)  7.41 × 10-11

Question 17

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 18

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

Accepted Answer

A)  4 × 10-1 
B)  1 × 10-2 
C)  1 × 102 
D)  1 × 10-15 
A)  4 × 10-1 
B)  1 × 10-2 
C)  1 × 102 
D)  1 × 10-15

Question 19

Which of the following is true of activation energy?

Accepted Answer

A)  Reactions with low activation energies are rapid. 
B)  The activation energy for an exothermic reaction is negative. 
C)  The activation energy is the energy difference between the reactants and the products. 
D)  Reactions with low activation energies have lower number of effective collisions. 
A)  Reactions with low activation energies are rapid. 
B)  The activation energy for an exothermic reaction is negative. 
C)  The activation energy is the energy difference between the reactants and the products. 
D)  Reactions with low activation energies have lower number of effective collisions.

Question 20

For 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 min), 0.070 L of O2 is present. After 15 min, the volume of O2 is 0.40 L. What is the rate of reaction?

Accepted Answer

A)  0.022 L/min 
B)  0.033 L/min 
C)  0.23 L/min 
D)  0.33 L/min 
A)  0.022 L/min 
B)  0.033 L/min 
C)  0.23 L/min 
D)  0.33 L/min

Exam 7: Reaction Rates and Chemical Equilibrium

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

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?

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

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

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

Consider the following graph. The graph is based on data collected from the following reaction. If Curve B presently represents C2H5OH, how would the graph change if this line represented CH3COOH?

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

Given that the reaction 2Na2O (s) → 4Na(s) + 2O2(g) is endothermic, which of the following is true of the reaction 4Na(s) + 2O2(g) → 2Na2O(s)?

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

How does a decrease in temperature affect an endothermic reaction that has not reached equilibrium?

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

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

Which of the following is an example of an equilibrium situation?

Which of the following symbols is used to denote a reversible reaction?

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 1.5 × 10-5. What is the equilibrium constant for the following reaction?

For the reaction equilibrium is established at 472°C when [H2] =0.0400 M, [N2] = 0.0200 M, and [NH3] = 1.074 × 10-7M. What is the equilibrium constant for this reaction?

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

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

Which of the following is true of activation energy?

For 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 min), 0.070 L of O2 is present. After 15 min, the volume of O2 is 0.40 L. What is the rate of 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, Alkynes, and Aromatic Compounds

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

Consider the following graph. The graph is based on data collected from the following reaction. If Curve B presently represents C₂H₅OH, how would the graph change if this line represented CH₃COOH?

Given that the reaction 2Na₂O (s) → 4Na(s) + 2O₂(g) is endothermic, which of the following is true of the reaction 4Na(s) + 2O₂(g) → 2Na₂O(s)?

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

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 1.5 × 10^-5. What is the equilibrium constant for the following reaction?

For the reaction equilibrium is established at 472°C when [H₂] =0.0400 M, [N₂] = 0.0200 M, and [NH₃] = 1.074 × 10^-7M. What is the equilibrium constant for this reaction?

For 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 min), 0.070 L of O₂ is present. After 15 min, the volume of O₂ is 0.40 L. What is the rate of reaction?