Question 1

Why don't the electrodes of a fuel cell deteriorate the way the electrodes of a battery do?

Accepted Answer

A) As long as fuel is supplied, fuel cells don't run down, but car batteries die when the electron-producing chemicals are consumed. 
B) Fuel cell electrodes are made of graphite, which does not deteriorate. 
C) Fuel cell electrodes are self-replenishing thanks to the KOH-containing paste. 
D) Fuel cell do not use electrodes, so there are none to deteriorate. 
A) As long as fuel is supplied, fuel cells don't run down, but car batteries die when the electron-producing chemicals are consumed. 
B) Fuel cell electrodes are made of graphite, which does not deteriorate. 
C) Fuel cell electrodes are self-replenishing thanks to the KOH-containing paste. 
D) Fuel cell do not use electrodes, so there are none to deteriorate.

Question 2

The following set of redox reactions takes place when iron is dipped into a solution of copper ions. Fe → Fe2+ + 2e-
Cu2+ + 2e- → Cu
Which of the following describes what is happening with the electrons in the solution?

Accepted Answer

A) The iron metal is releasing electrons and they are traveling to the copper ions. 
B) The copper is releasing electrons and they are traveling to the iron ions. 
C) The iron ions are gaining electrons from the copper metal. 
D) The copper ions are releasing electrons and they are traveling to the iron metal. 
E) none of the above 
A) The iron metal is releasing electrons and they are traveling to the copper ions. 
B) The copper is releasing electrons and they are traveling to the iron ions. 
C) The iron ions are gaining electrons from the copper metal. 
D) The copper ions are releasing electrons and they are traveling to the iron metal. 
E) none of the above

Question 3

Jewelry is often manufactured by electroplating an expensive metal such as gold over a cheaper metal. A setup for this process can be sketched as follows:   What would happen if the battery connections were suddenly reversed?

Accepted Answer

A) The ring would continue to electroplate with gold. 
B) Gold ions in solution would get reduced and settle to the bottom of the container. 
C) Gold ions in solution would begin to electroplate onto the gold electrode. 
D) All electrolysis would stop. 
A) The ring would continue to electroplate with gold. 
B) Gold ions in solution would get reduced and settle to the bottom of the container. 
C) Gold ions in solution would begin to electroplate onto the gold electrode. 
D) All electrolysis would stop.

Question 4

How are most metals found in nature?

Accepted Answer

A) as ionic compounds 
B) as free ions 
C) as native metals 
D) as covalent compounds 
E) all of the above 
A) as ionic compounds 
B) as free ions 
C) as native metals 
D) as covalent compounds 
E) all of the above

Question 5

Which of the following statements about electrochemistry is not true?

Accepted Answer

A) It is the study of how electrical energy and chemical reactions are related. 
B) It involves the use of a set of oxidation-reduction reactions to produce electrical current. 
C) It involves the use of electrical current to produce an oxidation-reduction reaction. 
D) It is the study of how electrons are transferred from one chemical compound to another. 
E) All of the above are true. 
A) It is the study of how electrical energy and chemical reactions are related. 
B) It involves the use of a set of oxidation-reduction reactions to produce electrical current. 
C) It involves the use of electrical current to produce an oxidation-reduction reaction. 
D) It is the study of how electrons are transferred from one chemical compound to another. 
E) All of the above are true.

Question 6

Why might disposing of a lead-acid battery, nickel-cadmium battery or mercury battery in a landfill be a bad thing?

Accepted Answer

A) Cadmium, mercury, and lead are all toxic metals and could leak out of the landfill. 
B) Cadmium, mercury, and lead are all very reactive and generate highly unstable compounds. 
C) Cadmium, mercury, and lead are all radioactive and release radiation. 
D) all of the above 
E) none of the above 
A) Cadmium, mercury, and lead are all toxic metals and could leak out of the landfill. 
B) Cadmium, mercury, and lead are all very reactive and generate highly unstable compounds. 
C) Cadmium, mercury, and lead are all radioactive and release radiation. 
D) all of the above 
E) none of the above

Question 7

Thin-film photovoltaic cells are ________.

Accepted Answer

A) composed of crystalline silicon 
B) easy to mass produce 
C) sensitive to only narrow regions of the visible spectrum 
D) very expensive to produce 
E) none of the above 
A) composed of crystalline silicon 
B) easy to mass produce 
C) sensitive to only narrow regions of the visible spectrum 
D) very expensive to produce 
E) none of the above

Question 8

Which of the following statements best describes an anode?

Accepted Answer

A) the negatively charged electrode of a battery or electrochemical apparatus 
B) the place where oxidation is taking place in a battery or electrochemical apparatus 
C) the place from which electrons are flowing away from 
D) all of the above 
E) none of the above 
A) the negatively charged electrode of a battery or electrochemical apparatus 
B) the place where oxidation is taking place in a battery or electrochemical apparatus 
C) the place from which electrons are flowing away from 
D) all of the above 
E) none of the above

Question 9

Which of the following species is the reducing agent? 2 CuBr → 2Cu + Br2

Accepted Answer

A) Cu 
B) CuBr 
C) Cu+ 
D) Br- 
E) Br2 
A) Cu 
B) CuBr 
C) Cu+ 
D) Br- 
E) Br2

Question 10

One of the products of combustion is water. Why doesn't this water extinguish the combustion?

Accepted Answer

A) While areas of combustion are being extinguished, new areas are combusting. 
B) Combustion only produces micro amounts of water. 
C) The chemical combustion reaction is happening too fast for the water to have an effect on the fire. 
D) This water is in the gaseous phase and merely floats away from the fire. 
A) While areas of combustion are being extinguished, new areas are combusting. 
B) Combustion only produces micro amounts of water. 
C) The chemical combustion reaction is happening too fast for the water to have an effect on the fire. 
D) This water is in the gaseous phase and merely floats away from the fire.

Question 11

Sodium metal is ________.

Accepted Answer

A) oxidized in the production of aluminum 
B) reduced in the production of aluminum 
C) both oxidized and reduced in the production of aluminum 
D) neither oxidized nor reduced in the production of aluminum 
A) oxidized in the production of aluminum 
B) reduced in the production of aluminum 
C) both oxidized and reduced in the production of aluminum 
D) neither oxidized nor reduced in the production of aluminum

Question 12

The general chemical equation for photosynthesis is shown below. Through this reaction is the carbon oxidized or reduced? How can you tell? 6   + 6   O →   + 6

Accepted Answer

A) Oxidized, since carbon is in the +4 oxidation state in   but in the +6 oxidation state in the product,   , glucose. 
B) Reduced, since in carbon dioxide there are two oxygen atoms for every one carbon but within the product,   , (glucose), there is only one oxygen for every one carbon. 
C) Neither, since carbon does not change its oxidation state and is neither oxidized nor reduced. 
D) Both, since the carbon atoms within the glucose molecules display two different charge states. 
A) Oxidized, since carbon is in the +4 oxidation state in   but in the +6 oxidation state in the product,   , glucose. 
B) Reduced, since in carbon dioxide there are two oxygen atoms for every one carbon but within the product,   , (glucose), there is only one oxygen for every one carbon. 
C) Neither, since carbon does not change its oxidation state and is neither oxidized nor reduced. 
D) Both, since the carbon atoms within the glucose molecules display two different charge states.

Question 13

In the above diagram, which atom is oxidized, the darker colored atom or the lighter colored atom?

Accepted Answer

A) Both of the atoms are oxidized. 
B) Neither of the atoms is oxidized. 
C) Only the darker colored atom is oxidized. 
D) Only the lighter colored atom is oxidized. 
A) Both of the atoms are oxidized. 
B) Neither of the atoms is oxidized. 
C) Only the darker colored atom is oxidized. 
D) Only the lighter colored atom is oxidized.

Question 14

Which of the following statements is untrue about oxidation and reduction processes?

Accepted Answer

A) An oxidation can happen without a reduction. 
B) It involves the exchange of electrons. 
C) Often ions are generated or consumed. 
D) Electrons are often involved in oxidation and reduction reactions. 
E) All of the above are true. 
A) An oxidation can happen without a reduction. 
B) It involves the exchange of electrons. 
C) Often ions are generated or consumed. 
D) Electrons are often involved in oxidation and reduction reactions. 
E) All of the above are true.

Question 15

Rust has a tendency to form when iron in contact with water reacts according to the following reaction: 4 Fe + 3 O2 → 2 Fe2O3
What is happening at the anodic region?

Accepted Answer

A) Iron is being oxidized. 
B) Oxygen is being oxidized. 
C) Oxygen is being reduced. 
D) Iron is being reduced. 
E) none of the above 
A) Iron is being oxidized. 
B) Oxygen is being oxidized. 
C) Oxygen is being reduced. 
D) Iron is being reduced. 
E) none of the above

Question 16

How does a blast furnace work?

Accepted Answer

A) A reductant is added that reacts with oxygen atoms at high temperature. 
B) The high temperature reduces the metal. 
C) The high temperature oxidizes the metal 
D) An oxidant is added that reacts with iron atoms at high temperature. 
E) none of the above 
A) A reductant is added that reacts with oxygen atoms at high temperature. 
B) The high temperature reduces the metal. 
C) The high temperature oxidizes the metal 
D) An oxidant is added that reacts with iron atoms at high temperature. 
E) none of the above

Question 17

Which of the following materials is most likely to undergo reduction?

Accepted Answer

A) Na 
B) Na+ 
C) Cl2 
D) Cl- 
E) both A and B 
A) Na 
B) Na+ 
C) Cl2 
D) Cl- 
E) both A and B

Question 18

Which of the following species is undergoing reduction? 2 CuBr → 2Cu + Br2

Accepted Answer

A) Cu 
B) CuBr 
C) Cu+ 
D) Br- 
E) Br2 
A) Cu 
B) CuBr 
C) Cu+ 
D) Br- 
E) Br2

Why don't the electrodes of a fuel cell deteriorate the way the electrodes of a battery do?

The following set of redox reactions takes place when iron is dipped into a solution of copper ions. Fe → Fe²⁺ + 2e- Cu²⁺ + 2e- → Cu Which of the following describes what is happening with the electrons in the solution?

Jewelry is often manufactured by electroplating an expensive metal such as gold over a cheaper metal. A setup for this process can be sketched as follows: What would happen if the battery connections were suddenly reversed?

How are most metals found in nature?

Which of the following statements about electrochemistry is not true?

Why might disposing of a lead-acid battery, nickel-cadmium battery or mercury battery in a landfill be a bad thing?

Thin-film photovoltaic cells are ________.

Which of the following statements best describes an anode?

Which of the following species is the reducing agent? 2 CuBr → 2Cu + Br₂

One of the products of combustion is water. Why doesn't this water extinguish the combustion?

Sodium metal is ________.

The general chemical equation for photosynthesis is shown below. Through this reaction is the carbon oxidized or reduced? How can you tell? 6 + 6 O → + 6

In the above diagram, which atom is oxidized, the darker colored atom or the lighter colored atom?

Which of the following statements is untrue about oxidation and reduction processes?

Rust has a tendency to form when iron in contact with water reacts according to the following reaction: 4 Fe + 3 O₂ → 2 Fe₂O₃ _{What is happening at the anodic region?}

How does a blast furnace work?

Which of the following materials is most likely to undergo reduction?

Which of the following species is undergoing reduction? 2 CuBr → 2Cu + Br₂

About Science

Particles of Matter

Elements of Chemistry

Subatomic Particles

The Atomic Nucleus

How Atoms Bond

How Molecules Mix

How Water Behaves

How Chemicals React

Acids and Bases in Our Environment

Organic Compounds

Nutrients of Life

Medicinal Chemistry

Optimizing Food Production

Protection Water and Air Resources

Capturing Energy

Filters

Exam 11: Oxidations and Reductions Charge the World

Why don't the electrodes of a fuel cell deteriorate the way the electrodes of a battery do?

The following set of redox reactions takes place when iron is dipped into a solution of copper ions. Fe → Fe2+ + 2e- Cu2+ + 2e- → Cu Which of the following describes what is happening with the electrons in the solution?

Jewelry is often manufactured by electroplating an expensive metal such as gold over a cheaper metal. A setup for this process can be sketched as follows: What would happen if the battery connections were suddenly reversed?

How are most metals found in nature?

Which of the following statements about electrochemistry is not true?

Why might disposing of a lead-acid battery, nickel-cadmium battery or mercury battery in a landfill be a bad thing?

Thin-film photovoltaic cells are ________.

Which of the following statements best describes an anode?

Which of the following species is the reducing agent? 2 CuBr → 2Cu + Br2

One of the products of combustion is water. Why doesn't this water extinguish the combustion?

Sodium metal is ________.

The general chemical equation for photosynthesis is shown below. Through this reaction is the carbon oxidized or reduced? How can you tell? 6 + 6 O → + 6

In the above diagram, which atom is oxidized, the darker colored atom or the lighter colored atom?

Which of the following statements is untrue about oxidation and reduction processes?

Rust has a tendency to form when iron in contact with water reacts according to the following reaction: 4 Fe + 3 O2 → 2 Fe2O3 What is happening at the anodic region?

How does a blast furnace work?

Which of the following materials is most likely to undergo reduction?

Which of the following species is undergoing reduction? 2 CuBr → 2Cu + Br2

About Science

Particles of Matter

Elements of Chemistry

Subatomic Particles

The Atomic Nucleus

How Atoms Bond

How Molecules Mix

How Water Behaves

How Chemicals React

Acids and Bases in Our Environment

Organic Compounds

Nutrients of Life

Medicinal Chemistry

Optimizing Food Production

Protection Water and Air Resources

Capturing Energy

Filters

The following set of redox reactions takes place when iron is dipped into a solution of copper ions. Fe → Fe²⁺ + 2e- Cu²⁺ + 2e- → Cu Which of the following describes what is happening with the electrons in the solution?

Which of the following species is the reducing agent? 2 CuBr → 2Cu + Br₂

Rust has a tendency to form when iron in contact with water reacts according to the following reaction: 4 Fe + 3 O₂ → 2 Fe₂O₃ _{What is happening at the anodic region?}

Which of the following species is undergoing reduction? 2 CuBr → 2Cu + Br₂