Question 1

In a battery, the following oxidation-reduction reactions are taking place: Mn₂O₃ + ZnO → 2 MnO₂ + Zn What is undergoing an oxidation as written?

Accepted Answer

The answer of In a battery, the following oxidation-reduction reactions...

Question 2

In one type of fuel cell, the following oxidation-reduction reactions are taking place: 2 H₂+ O₂ → 2 H₂O What is the oxidant?

Accepted Answer

The oxidant is the reactant being reduced, which is O₂ since it gains electrons to form O₂O.

Question 3

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

In Rxn B, MnO2 is gaining electrons (2e-) to form Mn2O3, which is the definition of reduction (gain of electrons).

Question 4

In a battery, the following two oxidation-reduction reactions are taking place: rxn A: Zn → Zn⁺² + 2e^- Rxn B: 2 NH₄⁺ + 2e^- → 2 NH₃ + H₂ Which reaction is taking place at the cathode?

Accepted Answer

Rxn B involves the reduction of H+ ions, which is happening at the cathode. In contrast, rxn A involves the oxidation of Zn, which is happening at the anode. Therefore, only rxn B is taking place at the cathode.

Question 5

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

Accepted Answer

Lead-acid, nickel-cadmium, and mercury batteries all contain toxic metals that could potentially leak out of a landfill and contaminate the surrounding environment. Disposing of these batteries in a landfill is not an environmentally responsible choice.

Question 6

In one type of fuel cell the following oxidation-reduction reactions are taking place: 2 H₂ + O₂ → 2 H₂O What is the fuel?

Accepted Answer

The fuel is the substance that is being oxidized in the fuel cell. In this case, the only substance being oxidized is H₂, so the answer is A. The other substances in the reaction are the oxidizing agent (O) and the product of the reaction (H₂O).

Question 7

In a battery, if the following oxidation-reduction reactions takes place normally: Mn₂O₃ + ZnO → 2 MnO₂ + Zn What reaction would be taking place if you were charging the battery?

Accepted Answer

The given reaction is the discharge reaction of the battery where Mn₂O₃ gets oxidized to MnO₂ and ZnO gets reduced to Zn. When we charge the battery, the opposite reaction takes place which is the oxidation of MnO₂ and the reduction of Zn back to ZnO. Therefore, the correct reaction for charging the battery would be 2 MnO₂ + Zn → Mn₂O₃ + ZnO. Option A is the only one that shows the reverse reaction, hence it is the correct answer. Options B and C do show individual reactions but they don't represent the overall reaction of charging the battery. Option D is incorrect because option B and C are not the complete reaction, and option A is already the correct answer. Option E is also incorrect because there is a specific reaction that takes place while charging the battery.

Question 8

In a battery, the following oxidation-reduction reactions are taking place: Mn₂O₃ + ZnO → 2 MnO₂ + Zn What is being formed at the cathode?

Accepted Answer

At the cathode, reduction takes place, which means electrons are gained. In the given reaction, ZnO is reduced to form Zn, which means Zn is being formed at the cathode. Therefore, option A is the correct answer.

Question 9

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

In reaction A, Zn is being oxidized since it loses electrons (2e-) and forms ZnO. In reaction B, H₂O is being reduced since it gains electrons (2e-) and forms Mn₂O₃.

Question 10

Your car lights were left on while you were shopping, and now your car battery is dead. Has the pH of the battery fluid increased or decreased?

Accepted Answer

The answer of Your car lights were left on while...

Question 11

What is one of the advantages of a fuel cell?

Accepted Answer

Fuel cells have the advantage of being able to run for a long time as long as fuel is added continuously. They are also more efficient than combustion and have lower emissions of pollutants. Therefore, all of the given options are advantages of a fuel cell.

Question 12

In a battery, the following oxidation-reduction reaction is taking place: Mn₂O₃ + ZnO → 2 MnO₂+ Zn What is undergoing reduction as written?

Accepted Answer

Reduction is the gain of electrons. In the given reaction, ZnO is gaining electrons to form Zn, hence undergoing reduction.

Question 13

Why is recycling of aluminum better for the environment than electrolysis of bauxite (an aluminum ore)?

Accepted Answer

It takes significantly less energy to recycle aluminum than to extract it from bauxite through electrolysis. This means that less fossil fuels are burned to power the process, resulting in lower greenhouse gas emissions and a smaller environmental impact overall. Additionally, recycling aluminum helps reduce the amount of waste in landfills, where it can take hundreds of years to degrade.

Question 14

How is electrolysis different from what is going on chemically inside a battery?

Accepted Answer

Electrolysis and battery operation are essentially the same process, but reversed. In a battery, chemical energy is converted into electrical energy by a spontaneous redox reaction. In electrolysis, electrical energy is used to drive a non-spontaneous redox reaction in order to produce chemical changes. Both processes involve the movement of electrons through a circuit, but the direction of electron flow is reversed.

Question 15

In a battery, the following oxidation-reduction reactions are taking place: Mn₂O₃ + ZnO → 2 MnO₂ + Zn What is being formed at the anode?

Accepted Answer

The answer of In a battery, the following oxidation-reduction reactions...

Question 16

Why does a battery that has thick zinc walls last longer than one that has thin zinc walls?

Accepted Answer

The zinc walls in a battery are part of the chemical reaction that generates electricity. As the battery is used, the zinc is gradually converted into zinc ions, meaning that thicker zinc walls can provide more material for the reaction, thereby allowing the battery to last longer.

Question 17

For the following electrolysis reaction: 2 AlOF₃^-2 + C → 2 Al + CO₂ + F^- Where would the aluminum form?

Accepted Answer

Aluminum will form at the cathode because it gains electrons during electrolysis.

Question 18

What is one of the drawbacks to using fuel cells?

Accepted Answer

Fuel cells often use hydrogen as a fuel, which is difficult to store and transport safely due to its high flammability and the fact that it is a gas at room temperature. This makes handling the fuel for fuel cells a significant drawback.

Question 19

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

Accepted Answer

Fuel cells continuously convert fuel into electricity as long as there is a supply of fuel and oxygen, unlike batteries which store a finite amount of energy and deteriorate as their chemical reactants are consumed.

Question 20

What is the primary difference between a fuel cell and a battery?

Accepted Answer

The primary difference between a fuel cell and a battery is that fuel cells can be refueled and do not run down like batteries which need to be recharged.

Quiz 18: Two Classes of Chemical Reactions

In a battery, the following oxidation-reduction reactions are taking place: Mn₂O₃ + ZnO → 2 MnO₂ + Zn What is undergoing an oxidation as written?

In one type of fuel cell, the following oxidation-reduction reactions are taking place: 2 H₂+ O₂ → 2 H₂O What is the oxidant?

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?

In a battery, the following two oxidation-reduction reactions are taking place: rxn A: Zn → Zn⁺² + 2e^- Rxn B: 2 NH₄⁺ + 2e^- → 2 NH₃ + H₂ Which reaction is taking place at the cathode?

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

In one type of fuel cell the following oxidation-reduction reactions are taking place: 2 H₂ + O₂ → 2 H₂O What is the fuel?

In a battery, if the following oxidation-reduction reactions takes place normally: Mn₂O₃ + ZnO → 2 MnO₂ + Zn What reaction would be taking place if you were charging the battery?

In a battery, the following oxidation-reduction reactions are taking place: Mn₂O₃ + ZnO → 2 MnO₂ + Zn What is being formed at the cathode?

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?

Your car lights were left on while you were shopping, and now your car battery is dead. Has the pH of the battery fluid increased or decreased?

What is one of the advantages of a fuel cell?

In a battery, the following oxidation-reduction reaction is taking place: Mn₂O₃ + ZnO → 2 MnO₂+ Zn What is undergoing reduction as written?

Why is recycling of aluminum better for the environment than electrolysis of bauxite (an aluminum ore) ?

How is electrolysis different from what is going on chemically inside a battery?

In a battery, the following oxidation-reduction reactions are taking place: Mn₂O₃ + ZnO → 2 MnO₂ + Zn What is being formed at the anode?

Why does a battery that has thick zinc walls last longer than one that has thin zinc walls?

For the following electrolysis reaction: 2 AlOF₃^-2 + C → 2 Al + CO₂ + F^- Where would the aluminum form?

What is one of the drawbacks to using fuel cells?

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

What is the primary difference between a fuel cell and a battery?

Quiz 18: Two Classes of Chemical Reactions

In a battery, the following oxidation-reduction reactions are taking place: Mn2O3 + ZnO → 2 MnO2 + Zn What is undergoing an oxidation as written?

In one type of fuel cell, the following oxidation-reduction reactions are taking place: 2 H2 + O2 → 2 H2O What is the oxidant?

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?

In a battery, the following two oxidation-reduction reactions are taking place: rxn A: Zn → Zn+2 + 2e- Rxn B: 2 NH4+ + 2e- → 2 NH3 + H2 Which reaction is taking place at the cathode?

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

In one type of fuel cell the following oxidation-reduction reactions are taking place: 2 H2 + O2 → 2 H2O What is the fuel?

In a battery, if the following oxidation-reduction reactions takes place normally: Mn2O3 + ZnO → 2 MnO2 + Zn What reaction would be taking place if you were charging the battery?

In a battery, the following oxidation-reduction reactions are taking place: Mn2O3 + ZnO → 2 MnO2 + Zn What is being formed at the cathode?

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?

Your car lights were left on while you were shopping, and now your car battery is dead. Has the pH of the battery fluid increased or decreased?

What is one of the advantages of a fuel cell?

In a battery, the following oxidation-reduction reaction is taking place: Mn2O3 + ZnO → 2 MnO2 + Zn What is undergoing reduction as written?

Why is recycling of aluminum better for the environment than electrolysis of bauxite (an aluminum ore) ?

How is electrolysis different from what is going on chemically inside a battery?

In a battery, the following oxidation-reduction reactions are taking place: Mn2O3 + ZnO → 2 MnO2 + Zn What is being formed at the anode?

Why does a battery that has thick zinc walls last longer than one that has thin zinc walls?

For the following electrolysis reaction: 2 AlOF3-2 + C → 2 Al + CO2 + F- Where would the aluminum form?

What is one of the drawbacks to using fuel cells?

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

What is the primary difference between a fuel cell and a battery?

In a battery, the following oxidation-reduction reactions are taking place: Mn₂O₃ + ZnO → 2 MnO₂ + Zn What is undergoing an oxidation as written?

In one type of fuel cell, the following oxidation-reduction reactions are taking place: 2 H₂+ O₂ → 2 H₂O What is the oxidant?

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?

In a battery, the following two oxidation-reduction reactions are taking place: rxn A: Zn → Zn⁺² + 2e^- Rxn B: 2 NH₄⁺ + 2e^- → 2 NH₃ + H₂ Which reaction is taking place at the cathode?

In one type of fuel cell the following oxidation-reduction reactions are taking place: 2 H₂ + O₂ → 2 H₂O What is the fuel?

In a battery, if the following oxidation-reduction reactions takes place normally: Mn₂O₃ + ZnO → 2 MnO₂ + Zn What reaction would be taking place if you were charging the battery?

In a battery, the following oxidation-reduction reactions are taking place: Mn₂O₃ + ZnO → 2 MnO₂ + Zn What is being formed at the cathode?

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 oxidation-reduction reaction is taking place: Mn₂O₃ + ZnO → 2 MnO₂+ Zn What is undergoing reduction as written?

In a battery, the following oxidation-reduction reactions are taking place: Mn₂O₃ + ZnO → 2 MnO₂ + Zn What is being formed at the anode?

For the following electrolysis reaction: 2 AlOF₃^-2 + C → 2 Al + CO₂ + F^- Where would the aluminum form?