Question 1

How does p-type silicon differ from pure silicon?

Accepted Answer

A) There are other elements with more valence electrons than silicon in the silicon matrix. 
B) There are extra positive charges in the silicon matrix. 
C) There are no positive charges available. 
D) There are other elements with less valence electrons than silicon in the silicon matrix. 
E) There are extra silicon atoms resulting in distortion of the silicon matrix. 
A) There are other elements with more valence electrons than silicon in the silicon matrix. 
B) There are extra positive charges in the silicon matrix. 
C) There are no positive charges available. 
D) There are other elements with less valence electrons than silicon in the silicon matrix. 
E) There are extra silicon atoms resulting in distortion of the silicon matrix.

Question 2

Zinc, Zn, is more easily oxidized than copper, Cu. What happens the moment after metal strips of these metals come into contact with each other?

Accepted Answer

A) The zinc metal immediately begins depositing electrons onto the surface of the copper, thus coating the copper with a white powder of zinc oxide, ZnO. 
B) The zinc metal begins to turn a greenish color indicating the presence of the formation of cupric oxide, CuO. 
C) The surface of the copper appears moist and cloudy as the zinc metal oxidizes and gets dissolved into   ions. 
D) Nothing happens. An immediate build up of charge in either material prevents continued oxidation-reduction from occurring. 
A) The zinc metal immediately begins depositing electrons onto the surface of the copper, thus coating the copper with a white powder of zinc oxide, ZnO. 
B) The zinc metal begins to turn a greenish color indicating the presence of the formation of cupric oxide, CuO. 
C) The surface of the copper appears moist and cloudy as the zinc metal oxidizes and gets dissolved into   ions. 
D) Nothing happens. An immediate build up of charge in either material prevents continued oxidation-reduction from occurring.

Question 3

Which direction do the photo-ejected electrons in a photovoltaic cell travel?

Accepted Answer

A) from the n-type, through a wire, to the p-type, and then back across the junction to the n-type silicon 
B) from the p-type, through a wire, to the n-type, and then back across the junction to the p-type silicon 
C) from the n-type, across the junction, into the p-type silicon 
D) from the p-type, across the junction, into the n-type silicon 
E) none of the above 
A) from the n-type, through a wire, to the p-type, and then back across the junction to the n-type silicon 
B) from the p-type, through a wire, to the n-type, and then back across the junction to the p-type silicon 
C) from the n-type, across the junction, into the p-type silicon 
D) from the p-type, across the junction, into the n-type silicon 
E) none of the above

Question 4

Why might coating a metal with another metal that is easier to oxidize prevent the first metal from being oxidized?

Accepted Answer

A) It doesn't prevent it, but helps to slow it down. 
B) All of the oxidizing agent is consumed by reacting with the easily oxidized metal. 
C) The metal that is coated is protected from moisture and oxygen so it doesn't react. 
D) The metal that is acting as the coating is protected from moisture and oxygen. 
E) all of the above 
A) It doesn't prevent it, but helps to slow it down. 
B) All of the oxidizing agent is consumed by reacting with the easily oxidized metal. 
C) The metal that is coated is protected from moisture and oxygen so it doesn't react. 
D) The metal that is acting as the coating is protected from moisture and oxygen. 
E) all of the above

Question 5

Water is 88.88 percent oxygen by mass. Oxygen is exactly what a fire needs to grow brighter and stronger. So why doesn't a fire grow brighter and stronger when water is added to it?

Accepted Answer

A) Oxygen in water is already "reduced" from the hydrogen atoms, so this oxygen atom no longer has a great attraction for additional electrons. 
B) The oxygen is chemically bound to hydrogen atoms. 
C) Oxygen in water is completely different from oxygen   , which is what is required for combustion. 
D) all of the above 
A) Oxygen in water is already "reduced" from the hydrogen atoms, so this oxygen atom no longer has a great attraction for additional electrons. 
B) The oxygen is chemically bound to hydrogen atoms. 
C) Oxygen in water is completely different from oxygen   , which is what is required for combustion. 
D) all of the above

Question 6

When lightning strikes, nitrogen molecules,   , and oxygen molecules,   , in the air react to form nitrates,   ⁻, which come down in the rain to help fertilize the soil. Is this this an example of oxidation or reduction?

Accepted Answer

A) The formation of nitrates is an example of oxidation. 
B) The formation of nitrates is an example of reduction. 
C) Both. The nitrogen is oxidized as it reacts with the oxygen while the oxygen is reduced. 
D) Neither. Although the bonds of both the   and   molecules are broken to form the   , neither oxidation nor reduction occurs. 
A) The formation of nitrates is an example of oxidation. 
B) The formation of nitrates is an example of reduction. 
C) Both. The nitrogen is oxidized as it reacts with the oxygen while the oxygen is reduced. 
D) Neither. Although the bonds of both the   and   molecules are broken to form the   , neither oxidation nor reduction occurs.

Question 7

Which of the following materials is most likely to act as an oxidizing agent?

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 8

Clorox is a laundry bleaching agent used to remove stains from white clothes. Suggest why the name begins with Clor- and ends with -ox.

Accepted Answer

A) Clor- because it has chlorine, -ox because it is as strong as an ox. 
B) The active ingredient contains chlorine atoms, which behave as strong oxidizing agents. 
C) Chlor- because it has chlorine ions, -ox because it is reduced. 
D) Chlor- because it has chlorine ions, -ox because it uses oxygen. 
A) Clor- because it has chlorine, -ox because it is as strong as an ox. 
B) The active ingredient contains chlorine atoms, which behave as strong oxidizing agents. 
C) Chlor- because it has chlorine ions, -ox because it is reduced. 
D) Chlor- because it has chlorine ions, -ox because it uses oxygen.

Question 9

What type of chemical reaction is involved in converting a metal salt into native metal?

Accepted Answer

A) an oxidation-reduction reaction 
B) an acid-base reaction 
C) an ion exchange reaction 
D) a phase change 
E) none of the above 
A) an oxidation-reduction reaction 
B) an acid-base reaction 
C) an ion exchange reaction 
D) a phase change 
E) none of the above

Question 10

The zinc within a copper penny does not oxidize because ________.

Accepted Answer

A) zinc is an inert metal 
B) it is not exposed to oxygen 
C) of an impossible build up of charge 
D) of a lack of water 
A) zinc is an inert metal 
B) it is not exposed to oxygen 
C) of an impossible build up of charge 
D) of a lack of water

Question 11

In a battery, the following two oxidation-reduction reactions are taking place: rxn A: Zn + 2 OH- → ZnO + H2O + 2e-
Rxn B: 2 MnO2 + H2O + 2e- → Mn2O3 + 2 OH-
What is undergoing oxidation?

Accepted Answer

A) Zn 
B) ZnO 
C) MnO2 
D) H2O 
E) OH- 
A) Zn 
B) ZnO 
C) MnO2 
D) H2O 
E) OH-

Question 12

Some car batteries require the periodic addition of water. Does adding the water increase or decrease the battery's ability to provide electric power to start the car?

Accepted Answer

A) It will decrease the battery's ability to provide electrical power because it will dilute the amount of ions in contact with the electrode. 
B) It will increase the battery's ability to provide electrical power because it will decrease the number of ions in contact with the electrode. 
C) It will decrease the battery's ability to provide electrical power because water increases the surface area of the electrode in contact with the solution. 
D) It will increase the battery's ability to provide electrical power because of the positive effect of diluting the ionic solution. 
A) It will decrease the battery's ability to provide electrical power because it will dilute the amount of ions in contact with the electrode. 
B) It will increase the battery's ability to provide electrical power because it will decrease the number of ions in contact with the electrode. 
C) It will decrease the battery's ability to provide electrical power because water increases the surface area of the electrode in contact with the solution. 
D) It will increase the battery's ability to provide electrical power because of the positive effect of diluting the ionic solution.

Question 13

What element is oxidized in the following equation and what element is reduced?   + 2 Ag → Sn + 2 Ag⁺

Accepted Answer

A) The tin ion,   , is oxidized, while the silver, Ag, is reduced. 
B) The tin ion,   , is reduced, while the silver, Ag, is oxidized. 
C) Both the tin ion,   , and the silver, Ag, are reduced. 
D) Both the tin ion,   , and the silver, Ag, are oxidized. 
A) The tin ion,   , is oxidized, while the silver, Ag, is reduced. 
B) The tin ion,   , is reduced, while the silver, Ag, is oxidized. 
C) Both the tin ion,   , and the silver, Ag, are reduced. 
D) Both the tin ion,   , and the silver, Ag, are oxidized.

Question 14

Why is the air over an open flame always moist?

Accepted Answer

A) The hot flame vaporizes the water in the air above the flame. 
B) One of the products of combustion is water vapor. 
C) Warm air contains more humidity than cold air. 
D) None of the above is true. 
A) The hot flame vaporizes the water in the air above the flame. 
B) One of the products of combustion is water vapor. 
C) Warm air contains more humidity than cold air. 
D) None of the above is true.

Question 15

Copper atoms have a greater tendency to be reduced than iron atoms do. Was this good news or bad news for the Statue of Liberty, whose copper exterior was originally held together by steel rivets?

Accepted Answer

A) This was good news since the steel rivets prevented the copper from eroding. 
B) Electrons will preferentially flow from the iron to the copper and then onto oxygen. Corrosion is thus accelerated around the interface of these two metals. 
C) This combination of metals have no effect on each other and that is why engineers chose to use them together. 
D) This combination of metals caused the copper to oxidize and turn green. 
A) This was good news since the steel rivets prevented the copper from eroding. 
B) Electrons will preferentially flow from the iron to the copper and then onto oxygen. Corrosion is thus accelerated around the interface of these two metals. 
C) This combination of metals have no effect on each other and that is why engineers chose to use them together. 
D) This combination of metals caused the copper to oxidize and turn green.

Question 16

The following set of redox reactions takes place as shown.   If you had two containers filled with the ion solution described above with a wire connecting a piece of iron (in container A)and a piece of copper (in container B)and a salt-bridge connecting the two containers, which way do the electrons flow?

Accepted Answer

A) There is no continuous flow of electrons. 
B) The electrons flow from container A to container B. 
C) The electrons flow from container B to container A. 
D) The electrons flow back and forth between the two containers. 
E) The electrons only move in the containers they originate in. 
A) There is no continuous flow of electrons. 
B) The electrons flow from container A to container B. 
C) The electrons flow from container B to container A. 
D) The electrons flow back and forth between the two containers. 
E) The electrons only move in the containers they originate in.

Question 17

What element is behaves as the oxidizing agent in the following equation and what element behaves as the reducing agent?   + 2 Ag → Sn + 2 Ag⁺

Accepted Answer

A) The tin ion,   , is the oxidizing agent while silver, Ag, is the reducing agent. 
B) The tin ion, Sn2+, is the reducing agent while silver, Ag, is the oxidizing agent. 
C) The tin, Sn, is the reducing agent while silver ion, Ag⁺, is the oxidizing agent. 
D) The tin, Sn, is the oxidizing agent while silver ion,Ag⁺, is the reducing agent. 
A) The tin ion,   , is the oxidizing agent while silver, Ag, is the reducing agent. 
B) The tin ion, Sn2+, is the reducing agent while silver, Ag, is the oxidizing agent. 
C) The tin, Sn, is the reducing agent while silver ion, Ag⁺, is the oxidizing agent. 
D) The tin, Sn, is the oxidizing agent while silver ion,Ag⁺, is the reducing agent.

Question 18

In a battery, the following two oxidation-reduction reactions are taking place: rxn A: Zn + 2 OH- → ZnO + H2O + 2e-
Rxn B: 2 MnO2 + H2O + 2e- → Mn2O3 + 2 OH-
What is undergoing reduction?

Accepted Answer

A) Zn 
B) ZnO 
C) MnO2 
D) H2O 
E) OH- 
A) Zn 
B) ZnO 
C) MnO2 
D) H2O 
E) OH-

Question 19

The following set of redox reactions takes place as shown.   If you had two containers filled with the ion solution described above with only a wire connecting a piece of iron (in container A)and a piece of copper (in container B), describe what happens.

Accepted Answer

A) A little bit of iron is converted into iron ions and a little bit of copper ion is converted into copper metal. 
B) All of the iron is transformed into iron ions and all of the copper is transformed into copper ions. 
C) All of the iron is transformed into iron ions and all of the copper ions are transformed into copper metal. 
D) All of the iron ions are transformed into iron metal and all of the copper is transformed into copper ions. 
E) All of the iron ions are transformed into iron metal and all of the copper is transformed into copper metal. 
A) A little bit of iron is converted into iron ions and a little bit of copper ion is converted into copper metal. 
B) All of the iron is transformed into iron ions and all of the copper is transformed into copper ions. 
C) All of the iron is transformed into iron ions and all of the copper ions are transformed into copper metal. 
D) All of the iron ions are transformed into iron metal and all of the copper is transformed into copper ions. 
E) All of the iron ions are transformed into iron metal and all of the copper is transformed into copper metal.

Question 20

Which of the following metals would be the easiest to reduce to its native form from an ore?

Accepted Answer

A) Zn 
B) Ni 
C) Fe 
D) Ti 
E) K 
A) Zn 
B) Ni 
C) Fe 
D) Ti 
E) K

How does p-type silicon differ from pure silicon?

Zinc, Zn, is more easily oxidized than copper, Cu. What happens the moment after metal strips of these metals come into contact with each other?

Which direction do the photo-ejected electrons in a photovoltaic cell travel?

Why might coating a metal with another metal that is easier to oxidize prevent the first metal from being oxidized?

Water is 88.88 percent oxygen by mass. Oxygen is exactly what a fire needs to grow brighter and stronger. So why doesn't a fire grow brighter and stronger when water is added to it?

When lightning strikes, nitrogen molecules, , and oxygen molecules, , in the air react to form nitrates, ⁻, which come down in the rain to help fertilize the soil. Is this this an example of oxidation or reduction?

Which of the following materials is most likely to act as an oxidizing agent?

Clorox is a laundry bleaching agent used to remove stains from white clothes. Suggest why the name begins with Clor- and ends with -ox.

What type of chemical reaction is involved in converting a metal salt into native metal?

The zinc within a copper penny does not oxidize because ________.

In a battery, the following two oxidation-reduction reactions are taking place: rxn A: Zn + 2 OH^- → ZnO + H₂O + 2e^- Rxn B: 2 MnO₂ + H₂O + 2e^- → Mn₂O₃ + 2 OH^- What is undergoing oxidation?

Some car batteries require the periodic addition of water. Does adding the water increase or decrease the battery's ability to provide electric power to start the car?

What element is oxidized in the following equation and what element is reduced? + 2 Ag → Sn + 2 Ag⁺

Why is the air over an open flame always moist?

Copper atoms have a greater tendency to be reduced than iron atoms do. Was this good news or bad news for the Statue of Liberty, whose copper exterior was originally held together by steel rivets?

What element is behaves as the oxidizing agent in the following equation and what element behaves as the reducing agent? + 2 Ag → Sn + 2 Ag⁺

In a battery, the following two oxidation-reduction reactions are taking place: rxn A: Zn + 2 OH^- → ZnO + H₂O + 2e^- Rxn B: 2 MnO₂ + H₂O + 2e^- → Mn₂O₃+ 2 OH^- What is undergoing reduction?

The following set of redox reactions takes place as shown. If you had two containers filled with the ion solution described above with only a wire connecting a piece of iron (in container A)and a piece of copper (in container B), describe what happens.

Which of the following metals would be the easiest to reduce to its native form from an ore?

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

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Exam 11: Oxidations and Reductions Charge the World

How does p-type silicon differ from pure silicon?

Zinc, Zn, is more easily oxidized than copper, Cu. What happens the moment after metal strips of these metals come into contact with each other?

Which direction do the photo-ejected electrons in a photovoltaic cell travel?

Why might coating a metal with another metal that is easier to oxidize prevent the first metal from being oxidized?

Water is 88.88 percent oxygen by mass. Oxygen is exactly what a fire needs to grow brighter and stronger. So why doesn't a fire grow brighter and stronger when water is added to it?

When lightning strikes, nitrogen molecules, , and oxygen molecules, , in the air react to form nitrates, ⁻, which come down in the rain to help fertilize the soil. Is this this an example of oxidation or reduction?

Which of the following materials is most likely to act as an oxidizing agent?

Clorox is a laundry bleaching agent used to remove stains from white clothes. Suggest why the name begins with Clor- and ends with -ox.

What type of chemical reaction is involved in converting a metal salt into native metal?

The zinc within a copper penny does not oxidize because ________.

In a battery, the following two oxidation-reduction reactions are taking place: rxn A: Zn + 2 OH- → ZnO + H2O + 2e- Rxn B: 2 MnO2 + H2O + 2e- → Mn2O3 + 2 OH- What is undergoing oxidation?

Some car batteries require the periodic addition of water. Does adding the water increase or decrease the battery's ability to provide electric power to start the car?

What element is oxidized in the following equation and what element is reduced? + 2 Ag → Sn + 2 Ag⁺

Why is the air over an open flame always moist?

Copper atoms have a greater tendency to be reduced than iron atoms do. Was this good news or bad news for the Statue of Liberty, whose copper exterior was originally held together by steel rivets?

What element is behaves as the oxidizing agent in the following equation and what element behaves as the reducing agent? + 2 Ag → Sn + 2 Ag⁺

In a battery, the following two oxidation-reduction reactions are taking place: rxn A: Zn + 2 OH- → ZnO + H2O + 2e- Rxn B: 2 MnO2 + H2O + 2e- → Mn2O3 + 2 OH- What is undergoing reduction?

The following set of redox reactions takes place as shown. If you had two containers filled with the ion solution described above with only a wire connecting a piece of iron (in container A)and a piece of copper (in container B), describe what happens.

Which of the following metals would be the easiest to reduce to its native form from an ore?

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

In a battery, the following two oxidation-reduction reactions are taking place: rxn A: Zn + 2 OH^- → ZnO + H₂O + 2e^- Rxn B: 2 MnO₂ + H₂O + 2e^- → Mn₂O₃ + 2 OH^- What is undergoing oxidation?

In a battery, the following two oxidation-reduction reactions are taking place: rxn A: Zn + 2 OH^- → ZnO + H₂O + 2e^- Rxn B: 2 MnO₂ + H₂O + 2e^- → Mn₂O₃+ 2 OH^- What is undergoing reduction?