Chem 1050 Ch. 7 Energy Storage quiz

The opposite of a galvanic cell is

an electrolytic cell

Chemical energy is converted directly into electrical energy in

A galvanic cell

During the chemical reaction in an electrochemical cell,

Oxidation occurs at the anode

Which is an oxidation half-reaction?

Zn--Zn2+ 2e-

Whenever a substance is oxidized,

some other substance must be reduced.

The current through a wire is most closely related to the,

Rate of electron flow through a wire

Which is the cathode in this galvanic cell?

The solid silver electrode

In an electrochemical cell, the anode is

The electrode at which oxidation takes place

In this electrochemical cell, the reduction half-reaction is

Cu2+(aq) + 2e- -----Cu(s)

Which is not a necessary consideration from a battery designed to run a cell phone or portable MP3 player?

It must use liquid, aqueous solutions

What condition must be met for a battery to be rechargeable?

The electrochemical reaction of the battery must be reversible

What is the primary determinant of the voltage developed by a battery?

The nature of the materials in the reaction

Very small mercury batteries have been made and used in a multitude of applications. Why have they been replaced by other kinds of batteries for most applications?

Mercury is poisonous and difficult to dispose of

Which type of widely used battery is not rechargeable?

Zinc-manganese alkaline

Why can the lead-acid batteries in cars generate electricity for several years before running down?

The mechanical motion of engine drives an alternator that generates electricity to recharge the battery

What type of battery is widely used to store the excess energy generated by windmill farms and solar panels?

Lead acid

Which type of battery is best for use in heart (cardiac) pacemakers?

Lithium-iodine

In a fuel cell,

Reduction takes place at the cathode

A major advantage of a fuel cell over a standard battery is that

As long as oxygen and fuel are supplied, a fuel cell will not run down like a battery will

Which is not a component of a fuel cell?

A timer

Which is NOT an advantage of using a solid electrolyte in a fuel cell?

It eliminates the need for an oxidant; only a fuel is required

How does using hydrogen as the fuel in an electric power plant compare with using hydrogen as the fuel in a fuel cell?

A fuel cell using hydrogen operates at a higher overall efficiency than would a power plant burning hydrogen as a fuel

As fuel cells become more widely accepted and are used more, we will

Be able to generate electricity in places where we cannot now do so

How does the reaction of hydrogen and oxygen to produce energy in a fuel cell differ from their interaction during the direct combustion of hydrogen and oxygen?

I, II, and III only

What is the purpose of the hot KOH solution in the fuel cell?

It maintains electroneutrality by working as an electrolyte; allowing transfer of ions between the half cells where the hydrogen and oxygen react

A fuel cell does not run down like a standard battery because

The reactants in a battery must be stored inside the battery, whereas the reactants for a fuel cell flow as needed

In general, a modern hybrid vehicle is polluting than a standard vehicle because it runs on both a

Gasoline engine and an electric motor run by a rechargeable battery

The pruis, a hybrid car produced by Toyota, uses a battery that its maker claims should not have to be recharged or replaced during the lifetime of the car. The type of battery used in the Prius is

Nickel-metal hydride

What moves in the salt bridge from the cathode to the anode?

Anions

At present, it will be difficult and perhaps inappropriate to develop an economy based on burning hydrogen rather than natural gas or gasoline because

Although hydrogen is abundant, pure hydrogen is not found naturally on earth. Hydrogen is difficult or expensive to isolate and collect

What energy change is associated with the reaction to obtain one mole of H2 from one mole of water vapor? The balanced equation is 2H2O(g)*2H2(g)+O2(g) and the relevant bond energies are: H-H=436 kJ/mol; H-O=467 kJ/mol; O-O=146 kJ/mol; O O=498 kJ/mol.

+249 kJ

For safety and other practical reasons, the most logical use for hydrogen as a fuel in the near future is

In a fuel cell

Which has not been suggested as a reasonably practical way to store large amounts of hydrogen in relatively small spaces for its use as a fuel?

Liquefy hydrogen under pressure and store it much as we do with liquefied natural gas today

Batteries must be used in addition to solar cells when generating household electricity because

Batteries must store and then supply the energy when sunlight is not available

The aluminum-air battery is being considered for use in automobiles. In this battery, aluminum metal undergoes oxidation to Al3+ ions and forms Al(OH)3. O2 from the air undergoes reduction to OH- ions. Which half-reactions occur at the anode?

Formation of Al3+ ions from aluminum

A NiCd battery uses nickel and cadmium to produce a potential difference. Using these equations, answer the following questions. Which equation represents what takes place at the anode?

II

Which equation represents the whole chemical reaction within the galvanic cell?

III

Which equation best represents the reduction half-reaction?

I

Electrolysis is a process that

requires an electrical current to decompose water into hydrogen gas and oxygen gas.

Which of the following statements is not true about PEM fuel cell?

PEM fuel cells rely on inexpensive catalysts

Reforming processes can store hydrogen fuel in a liquid form as another molecule. Which of the following cannot be reformed into hydrogen?

Carbon Dioxide

Why doesn't water naturally become hydrogen and oxygen gas when exposed to light?

Water doesn't absorb the proper wavelength of light to split

How do the interactions that are broken in water when it is boiled compare with those broken when water is electrolyzed?

Boiling water breaks intermolecular attractions and electrolysis breaks covalent bonds

Why is it so expensive to ship hydrogen as a liquid as is often done with other gas?

Hydrogen has to be shipped at a very low temperature

Consider Ohm's law. Which of the following are correct?

Voltage is proportional to current

For the compound Fe3O4, what is the oxidation state of Fe?

Mixture between 2+ and 3+

For the compound FeCl3, what is the oxidation state of Fe?

3+

Which of the following automotive energy storage devices would give rise to the fastest acceleration from zero to 60 mph?

Supercapacitors

Batteries are still preferred over supercapacitors for portable electric applications. What factor(s) give rise to this preference?

Supercapacitors have low energy densities

What are the typical units for specific energy?

Wh/kg