CH. 8 CONNECT

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The Prius, 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

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nickel-metal hydride.

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

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

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Which is not a component of a fuel cell?

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A timer

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?

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I. The direct combustion of hydrogen and oxygen produces several different products, whereas the fuel cell produces only water \n II. Much less heat energy is produced in a fuel cell than via direct combustion of hydrogen and oxygen \n III. The fuel cell is more useful for producing electricity than direct combustion. \n IV. It is much easier to control the hydrogen and oxygen during direct combustion than during their reaction in a fuel cell

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I, II, and III only

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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 in as needed.

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

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\n

The electrochemical reaction of the battery must be reversible

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During the chemical reaction in an electrochemical cell,

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oxidation occurs at the anode.

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

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Boiling water breaks intermolecular attractions and electrolysis breaks covalent bonds

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Whenever a substance is oxidized,

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some other substance must be reduced.

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A NiCd battery uses nickel and cadmium to produce a potential difference. Using these equations, answer the below question. \n \n I. 2NiO(OH) (s) + 2H2O(l) + 2e− → 2Ni(OH)2(s) + 2OH−(aq) \n II. Cd(s) + 2OH−(aq) → Cd(OH)2 (s) + 2e− \n III. Cd(s) + 2NiO(OH)(s) + 2H2O(l) → 2Ni(OH)2(s) + Cd(OH)2(s) \n \n Which equation best represents the reduction half-reaction?

I

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

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

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

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

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Consider Ohm’s Law. Which of the following are correct?

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Voltage is proportional to current

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

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

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The current through a wire is most closely related to the

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rate of electron flow through a wire

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The opposite of a galvanic cell is

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an electrolytic cell.

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Which is an oxidation half-reaction?

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Zn → Zn2+ + 2e−

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

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

A NiCd battery uses nickel and cadmium to produce a potential difference. Using these equations, answer the below question. \n \n I. 2NiO(OH)(s) + 2H2O(l) + 2e− → 2Ni(OH)2(s) + 2OH−(aq) \n II. Cd(s) + 2OH−(aq) → Cd(OH)2(s) + 2e− \n III. Cd(s) + 2NiO(OH)(s) + 2H2O(l) → 2Ni(OH)2(s) + Cd(OH)2(s) \n \n Which equation represents the whole chemical reaction within the galvanic cell?

III

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Which type of widely used battery is not rechargeable?

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Zinc-manganese alkaline

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Chemical energy is converted directly into electrical energy in

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a galvanic cell.

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

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3+

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

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

What energy change is associated with the reaction to obtain one mole of H2 from one mole of water vapor? The balanced equation is 2 H2O(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 

\+249 kJ

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

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Mixture between 2+ and 3+