Question 1

Which of A-D is a disadvantage in using hydrogen fuel cells instead of gasoline engines in vehicles?

Accepted Answer

A) It is difficult to store hydrogen safely. 
B) No distribution network of hydrogen fuel is in place. 
C) Hydrogen fuel must be produced, most likely from water, by using another energy source. 
D) Hydrogen fuel is not really a source of energy but rather is a way to store energy. 
E) All of the above. 
A) It is difficult to store hydrogen safely. 
B) No distribution network of hydrogen fuel is in place. 
C) Hydrogen fuel must be produced, most likely from water, by using another energy source. 
D) Hydrogen fuel is not really a source of energy but rather is a way to store energy. 
E) All of the above.

Question 2

How do fuel cells differ from traditional electrochemical cells (batteries)?

Accepted Answer

A) The supply of reactants is continually renewed. 
B) The cell potentials generally are lower. 
C) The cell potentials generally are higher. 
D) Fuel cells are closed systems; batteries are open systems. 
E) Fuel cells do not involve oxidation-reduction reactions. 
A) The supply of reactants is continually renewed. 
B) The cell potentials generally are lower. 
C) The cell potentials generally are higher. 
D) Fuel cells are closed systems; batteries are open systems. 
E) Fuel cells do not involve oxidation-reduction reactions.

Question 3

If the free-energy change of the following voltaic cell   is F1F1F1S1F1F1F10147.2 kJ, what is the standard potential of the cell?

Accepted Answer

A) (F1F1F1S1F1F1F100.763 V) 
B) (F1F1F1S1F1F1F100.763 V) 
C) (F1F1F1S1F1F1F101.53 V) 
D) (F1F1F1S1F1F1F101.53 V) 
E) (F1F1F1S1F1F1F102.12 V) 
A) (F1F1F1S1F1F1F100.763 V) 
B) (F1F1F1S1F1F1F100.763 V) 
C) (F1F1F1S1F1F1F101.53 V) 
D) (F1F1F1S1F1F1F101.53 V) 
E) (F1F1F1S1F1F1F102.12 V)

Question 4

Which statement about a voltaic cell is not correct?

Accepted Answer

A) Electrons are produced as a product at the cathode. 
B) Reduction occurs at the cathode. 
C) Usually the cathode is a metal strip. 
D) In the external circuit, electrons flow toward the cathode. 
E) Chemical species can have their oxidation numbers decreased at the cathode. 
A) Electrons are produced as a product at the cathode. 
B) Reduction occurs at the cathode. 
C) Usually the cathode is a metal strip. 
D) In the external circuit, electrons flow toward the cathode. 
E) Chemical species can have their oxidation numbers decreased at the cathode.

Question 5

How many kilograms of aluminum metal can be produced by the electrolysis of Al2O3 using a current of 100 amperes for 24 hours?

Accepted Answer

A) 0.81 kg 
B) 2.4 kg 
C) 810 kg 
D) 2.2 F1F1F1S1F1F1F10 1013 kg 
E) 7.5 F1F1F1S1F1F1F10 1012 kg 
A) 0.81 kg 
B) 2.4 kg 
C) 810 kg 
D) 2.2 F1F1F1S1F1F1F10 1013 kg 
E) 7.5 F1F1F1S1F1F1F10 1012 kg

Question 6

Which cell diagram is correct for the following electrochemical cell?

Accepted Answer

A) Al(s)|Al3F1F1F1S1F1F1F10(aq) (0.50 M )||Ni(s)| Ni2F1F1F1S1F1F1F10(aq) (0.30 M ) 
B) Ni(s)|Al3F1F1F1S1F1F1F10(aq) (0.50 M )|Ni2F1F1F1S1F1F1F10(aq) (0.30 M )|Al(s) 
C) Al(s)|Al3F1F1F1S1F1F1F10(aq) (0.50 M )||Ni2F1F1F1S1F1F1F10(aq) (0.30 M )|Ni(s) 
D) Ni2F1F1F1S1F1F1F10(aq) (0.30 M )|Ni(s)||Al3F1F1F1S1F1F1F10(aq) (0.50 M )|Al(s) 
E) Ni(s)|Ni2F1F1F1S1F1F1F10(aq) (0.30 M )||Al(s)|Al3F1F1F1S1F1F1F10(aq) (0.50 M ) 
A) Al(s)|Al3F1F1F1S1F1F1F10(aq) (0.50 M )||Ni(s)| Ni2F1F1F1S1F1F1F10(aq) (0.30 M ) 
B) Ni(s)|Al3F1F1F1S1F1F1F10(aq) (0.50 M )|Ni2F1F1F1S1F1F1F10(aq) (0.30 M )|Al(s) 
C) Al(s)|Al3F1F1F1S1F1F1F10(aq) (0.50 M )||Ni2F1F1F1S1F1F1F10(aq) (0.30 M )|Ni(s) 
D) Ni2F1F1F1S1F1F1F10(aq) (0.30 M )|Ni(s)||Al3F1F1F1S1F1F1F10(aq) (0.50 M )|Al(s) 
E) Ni(s)|Ni2F1F1F1S1F1F1F10(aq) (0.30 M )||Al(s)|Al3F1F1F1S1F1F1F10(aq) (0.50 M )

Question 7

What is true when a battery (voltaic cell) is dead ?

Accepted Answer

A)    F1F1F1S1F1F1F10 0 and Q F1F1F1S1F1F1F10 K 
B) Ecell F1F1F1S1F1F1F10 0 and Q F1F1F1S1F1F1F10 K 
C) Ecell F1F1F1S1F1F1F10 0 and Q F1F1F1S1F1F1F10 0 
D)    F1F1F1S1F1F1F10 0 and Q F1F1F1S1F1F1F10 0 
E) Ecell F1F1F1S1F1F1F10 0 and K F1F1F1S1F1F1F10 0 
A)    F1F1F1S1F1F1F10 0 and Q F1F1F1S1F1F1F10 K 
B) Ecell F1F1F1S1F1F1F10 0 and Q F1F1F1S1F1F1F10 K 
C) Ecell F1F1F1S1F1F1F10 0 and Q F1F1F1S1F1F1F10 0 
D)    F1F1F1S1F1F1F10 0 and Q F1F1F1S1F1F1F10 0 
E) Ecell F1F1F1S1F1F1F10 0 and K F1F1F1S1F1F1F10 0

Question 8

Does pH have an effect on the cell potential (Ecell) for the following oxidation-reduction reaction?

Accepted Answer

A) Yes, because Ecell values for all redox reactions depend on the pH. 
B) Yes, because Ecell values for redox reactions involving the hydronium ion depend on the pH. 
C) No, because Ecell values for redox reactions depend only on the major species in the reaction, in this case, Fe2F1F1F1S1F1F1F10, MnO4F1F1F1S1F1F1F10, Fe3F1F1F1S1F1F1F10, and Mn2F1F1F1S1F1F1F10. 
D) No, because Ecell values for redox reactions depend on concentrations and temperatures but not on pH. 
E) No, because Ecell values for redox reactions do not depend on the pH. 
A) Yes, because Ecell values for all redox reactions depend on the pH. 
B) Yes, because Ecell values for redox reactions involving the hydronium ion depend on the pH. 
C) No, because Ecell values for redox reactions depend only on the major species in the reaction, in this case, Fe2F1F1F1S1F1F1F10, MnO4F1F1F1S1F1F1F10, Fe3F1F1F1S1F1F1F10, and Mn2F1F1F1S1F1F1F10. 
D) No, because Ecell values for redox reactions depend on concentrations and temperatures but not on pH. 
E) No, because Ecell values for redox reactions do not depend on the pH.

Question 9

If 15 g of aluminum from an empty soda can could be used as an anode of a battery, how long could it supply a current of 10 amps?

Accepted Answer

A) 45 hr 
B) 15 hr 
C) 5.4 hr 
D) 4.5 hr 
E) 1.5 hr 
A) 45 hr 
B) 15 hr 
C) 5.4 hr 
D) 4.5 hr 
E) 1.5 hr

Question 10

A typical D battery has a capacity of 12 ampere-hours (A F1F1F1S1F1F1F10 hr). How many electrons can such a battery supply?

Accepted Answer

A) 4.3 F1F1F1S1F1F1F10 104 
B) 2.7 F1F1F1S1F1F1F10 1023 
C) 4.2 F1F1F1S1F1F1F10 106 
D) 3.6 F1F1F1S1F1F1F10 1023 
E) 4.1 F1F1F1S1F1F1F10 1018 
A) 4.3 F1F1F1S1F1F1F10 104 
B) 2.7 F1F1F1S1F1F1F10 1023 
C) 4.2 F1F1F1S1F1F1F10 106 
D) 3.6 F1F1F1S1F1F1F10 1023 
E) 4.1 F1F1F1S1F1F1F10 1018

Question 11

Zinc-air batteries are actively being researched because one reactant (oxygen) is provided in infinite supply for free. The standard cell potential for this battery is 1.65 V. Calculate the cell potential when the partial pressure of oxygen in the cell is 0.190 atm and the temperature is 25.0F1F1F1S1F1F1F10C. The reaction in the cell converts Zn(s) and O2(g) into ZnO(s).

Accepted Answer

A) 1.61 V 
B) 1.62 V 
C) 1.64 V 
D) 1.66 V 
E) 1.69 V 
A) 1.61 V 
B) 1.62 V 
C) 1.64 V 
D) 1.66 V 
E) 1.69 V

Question 12

Consider the following chemical reaction used to construct a voltaic cell   Which one of the following statements is correct?

Accepted Answer

A) MnCl2 is produced at the anode. 
B) ClF1F1F1S1F1F1F10 ions are reduced at the cathode. 
C) MnO2 is the reducing agent. 
D) Three moles of electrons are transferred in this reaction. 
E) Electrons travel from ClF1F1F1S1F1F1F10 to Mn4F1F1F1S1F1F1F10. 
A) MnCl2 is produced at the anode. 
B) ClF1F1F1S1F1F1F10 ions are reduced at the cathode. 
C) MnO2 is the reducing agent. 
D) Three moles of electrons are transferred in this reaction. 
E) Electrons travel from ClF1F1F1S1F1F1F10 to Mn4F1F1F1S1F1F1F10.

Question 13

A pH meter uses an electrode arrangement that provides a voltage that depends on [HF1F1F1S1F1F1F10], in accord with the Nernst equation. The following plot illustrates this dependence. What effect would changing temperature have on the measurement and this plot?

Accepted Answer

A) A change of temperature would have no effect. 
B) An increase in temperature would increase the slope. 
C) An increase in temperature would decrease the slope. 
D) An increase in temperature would increase the y intercept. 
E) An increase in temperature would decrease the y intercept. 
A) A change of temperature would have no effect. 
B) An increase in temperature would increase the slope. 
C) An increase in temperature would decrease the slope. 
D) An increase in temperature would increase the y intercept. 
E) An increase in temperature would decrease the y intercept.

Question 14

An electrochemical cell with a standard hydrogen electrode and a cathode consisting of a metallic chromium electrode, Cr(s), in contact with a 1.00 M chromium solution, Cr3F1F1F1S1F1F1F10(aq), was constructed. The voltage produced by this cell was measured at 25F1F1F1S1F1F1F10C. Which statements describe the results of this measurement, assuming the conditions are ideal? The cell voltage with the appropriate sign equals ________
I. the cell potential.
II. the electromotive force.
III. the standard cell potential.
IV. the standard reduction potential for Cr/Cr3F1F1F1S1F1F1F10.

Accepted Answer

A) I only 
B) I and II 
C) I, II, and III 
D) I, II, III, and IV 
E) III only 
A) I only 
B) I and II 
C) I, II, and III 
D) I, II, III, and IV 
E) III only

Question 15

A typical 1.5 V AAA battery has a capacity of 1 ampere-hour (A F1F1F1S1F1F1F10 hr). How much energy can such a battery supply?

Accepted Answer

A) 5,400 J 
B) 1.5 J 
C) 3,600 J 
D) 1,800 J 
E) 90 J 
A) 5,400 J 
B) 1.5 J 
C) 3,600 J 
D) 1,800 J 
E) 90 J

Question 16

The diagram below represents a voltaic cell. Which one of the statements about this cell is not correct? Zn(s)|Zn2F1F1F1S1F1F1F10(1.0 M)||Cu2F1F1F1S1F1F1F10(1.0 M)|Cu(s)

Accepted Answer

A) The mass of the zinc electrode decreases during discharge. 
B) The copper electrode is the anode. 
C) Electrons flow through the external circuit from the zinc electrode to the copper electrode. 
D) Reduction occurs at the copper electrode during discharge. 
E) The concentration of copper ions decreases during discharge. 
A) The mass of the zinc electrode decreases during discharge. 
B) The copper electrode is the anode. 
C) Electrons flow through the external circuit from the zinc electrode to the copper electrode. 
D) Reduction occurs at the copper electrode during discharge. 
E) The concentration of copper ions decreases during discharge.

Question 17

Lead is a toxic metal. The U.S. Environmental Protection Agency limits the concentration of lead ions in drinking water to less than 5 F1F1F1S1F1F1F10 10F1F1F1S1F1F1F108 M. Assess the feasibility of monitoring of lead in drinking water using a voltaic cell based on the following half-reactions.   EF1F1F1S1F1F1F10 F1F1F1S1F1F1F10 F1F1F1S1F1F1F100.762 V   EF1F1F1S1F1F1F10 F1F1F1S1F1F1F10 F1F1F1S1F1F1F100.126 V If the zinc ion concentration were 0.100 M, what lead ion concentration at 298 K would decrease the cell potential by 10 mV from the standard cell potential?

Accepted Answer

A) 0.012 M 
B) 0.22 M 
C) 0.046 M 
D) 0.15 M 
E) 0.022 M 
A) 0.012 M 
B) 0.22 M 
C) 0.046 M 
D) 0.15 M 
E) 0.022 M

Question 18

An electrochemical cell has both a silver anode and a silver cathode. The solutions of silver nitrate in contact with the electrodes have different concentrations. Which statement(s) correctly describe this cell?
I.The cell potential is 0.
II. The cell potential is negative.
III. The cell potential is positive.
IV. No electrons will flow through the external circuit.

Accepted Answer

A) I only 
B) II only 
C) III only 
D) I and IV 
E) II and IV 
A) I only 
B) II only 
C) III only 
D) I and IV 
E) II and IV

Question 19

The diagram below represents a voltaic cell. In this cell, the electron flow is from ________ Cd(s)|Cd2F1F1F1S1F1F1F10(aq)||Fe2F1F1F1S1F1F1F10(aq),Fe3F1F1F1S1F1F1F10(aq)|Pt(s)

Accepted Answer

A) Pt to Cd2F1F1F1S1F1F1F10. 
B) Pt to Cd. 
C) Fe2F1F1F1S1F1F1F10 to Cd2F1F1F1S1F1F1F10. 
D) Cd2F1F1F1S1F1F1F10 to Fe3F1F1F1S1F1F1F10. 
E) Cd to Fe3F1F1F1S1F1F1F10. 
A) Pt to Cd2F1F1F1S1F1F1F10. 
B) Pt to Cd. 
C) Fe2F1F1F1S1F1F1F10 to Cd2F1F1F1S1F1F1F10. 
D) Cd2F1F1F1S1F1F1F10 to Fe3F1F1F1S1F1F1F10. 
E) Cd to Fe3F1F1F1S1F1F1F10.

Question 20

Because of recent advances in recovery technology, the supply of natural gas, which is mostly methane, has increased significantly. If 1 mole of methane is consumed in a fuel cell powering an automobile, estimate the maximum amount of work that can be produced by the electric motor.
The data in the table below may be helpful.

Accepted Answer

Use the standard free-energies of format

Which of A-D is a disadvantage in using hydrogen fuel cells instead of gasoline engines in vehicles?

How do fuel cells differ from traditional electrochemical cells (batteries)?

If the free-energy change of the following voltaic cell is 147.2 kJ, what is the standard potential of the cell?

Which statement about a voltaic cell is not correct?

How many kilograms of aluminum metal can be produced by the electrolysis of Al₂O₃ using a current of 100 amperes for 24 hours?

Which cell diagram is correct for the following electrochemical cell?

What is true when a battery (voltaic cell) is dead ?

Does pH have an effect on the cell potential (E_cell) for the following oxidation-reduction reaction?

If 15 g of aluminum from an empty soda can could be used as an anode of a battery, how long could it supply a current of 10 amps?

A typical D battery has a capacity of 12 ampere-hours (A  hr). How many electrons can such a battery supply?

Consider the following chemical reaction used to construct a voltaic cell Which one of the following statements is correct?

A pH meter uses an electrode arrangement that provides a voltage that depends on [H^], in accord with the Nernst equation. The following plot illustrates this dependence. What effect would changing temperature have on the measurement and this plot?

A typical 1.5 V AAA battery has a capacity of 1 ampere-hour (A  hr). How much energy can such a battery supply?

The diagram below represents a voltaic cell. Which one of the statements about this cell is not correct? Zn(s)|Zn²^(1.0 M)||Cu²^(1.0 M)|Cu(s)

The diagram below represents a voltaic cell. In this cell, the electron flow is from ________ Cd(s)|Cd²^(aq)||Fe²^(aq),Fe³^(aq)|Pt(s)

Matter and Energy: The Origin of the Universe

Atoms, Ions, and Molecules: Matter Starts Here

Stoichiometry: Mass, Formulas, and Reactions

Solution Chemistry: The Hydrosphere

Thermochemistry: Energy Changes in Reactions

Properties of Gases: The Air We Breathe

A Quantum Model of Atoms: Waves and Particles

Chemical Bonds: What Makes a Gas a Greenhouse Gas

Molecular Geometry: Shape Determines Function

Intermolecular Forces: The Uniqueness of Water

Solutions: Properties and Behavior

Solids: Crystals, Alloys, and Polymers

Chemical Kinetics: Reactions in the Atmosphere

Chemical Equilibrium: How Much Product Does a Reaction Really Make

Acidbase Equilibria: Proton Transfer in Biological Systems

Additional Aqueous Equilibria: Chemistry and the Oceans

Thermodynamics: Spontaneous and Nonspontaneous Reactions and Processes

Nuclear Chemistry: Applications to Energy and Medicine

Organic and Biological Molecules: the Compounds of Life

The Main Group Elements: Life and the Periodic Table

Transition Metals: Biological and Medical Applications

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Exam 18: Electrochemistry: The Quest for Clean Energy

Which of A-D is a disadvantage in using hydrogen fuel cells instead of gasoline engines in vehicles?

How do fuel cells differ from traditional electrochemical cells (batteries)?

If the free-energy change of the following voltaic cell is 147.2 kJ, what is the standard potential of the cell?

Which statement about a voltaic cell is not correct?

How many kilograms of aluminum metal can be produced by the electrolysis of Al2O3 using a current of 100 amperes for 24 hours?

Which cell diagram is correct for the following electrochemical cell?

What is true when a battery (voltaic cell) is dead ?

Does pH have an effect on the cell potential (Ecell) for the following oxidation-reduction reaction?

If 15 g of aluminum from an empty soda can could be used as an anode of a battery, how long could it supply a current of 10 amps?

A typical D battery has a capacity of 12 ampere-hours (A  hr). How many electrons can such a battery supply?

Consider the following chemical reaction used to construct a voltaic cell Which one of the following statements is correct?

A pH meter uses an electrode arrangement that provides a voltage that depends on [H], in accord with the Nernst equation. The following plot illustrates this dependence. What effect would changing temperature have on the measurement and this plot?

A typical 1.5 V AAA battery has a capacity of 1 ampere-hour (A  hr). How much energy can such a battery supply?

The diagram below represents a voltaic cell. Which one of the statements about this cell is not correct? Zn(s)|Zn2(1.0 M)||Cu2(1.0 M)|Cu(s)

The diagram below represents a voltaic cell. In this cell, the electron flow is from ________ Cd(s)|Cd2(aq)||Fe2(aq),Fe3(aq)|Pt(s)

Matter and Energy: The Origin of the Universe

Atoms, Ions, and Molecules: Matter Starts Here

Stoichiometry: Mass, Formulas, and Reactions

Solution Chemistry: The Hydrosphere

Thermochemistry: Energy Changes in Reactions

Properties of Gases: The Air We Breathe

A Quantum Model of Atoms: Waves and Particles

Chemical Bonds: What Makes a Gas a Greenhouse Gas

Molecular Geometry: Shape Determines Function

Intermolecular Forces: The Uniqueness of Water

Solutions: Properties and Behavior

Solids: Crystals, Alloys, and Polymers

Chemical Kinetics: Reactions in the Atmosphere

Chemical Equilibrium: How Much Product Does a Reaction Really Make

Acidbase Equilibria: Proton Transfer in Biological Systems

Additional Aqueous Equilibria: Chemistry and the Oceans

Thermodynamics: Spontaneous and Nonspontaneous Reactions and Processes

Nuclear Chemistry: Applications to Energy and Medicine

Organic and Biological Molecules: the Compounds of Life

The Main Group Elements: Life and the Periodic Table

Transition Metals: Biological and Medical Applications

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How many kilograms of aluminum metal can be produced by the electrolysis of Al₂O₃ using a current of 100 amperes for 24 hours?

Does pH have an effect on the cell potential (E_cell) for the following oxidation-reduction reaction?

A pH meter uses an electrode arrangement that provides a voltage that depends on [H^], in accord with the Nernst equation. The following plot illustrates this dependence. What effect would changing temperature have on the measurement and this plot?

The diagram below represents a voltaic cell. Which one of the statements about this cell is not correct? Zn(s)|Zn²^(1.0 M)||Cu²^(1.0 M)|Cu(s)

The diagram below represents a voltaic cell. In this cell, the electron flow is from ________ Cd(s)|Cd²^(aq)||Fe²^(aq),Fe³^(aq)|Pt(s)