chem 106 ch 7 study guide

Which is not a component of a fuel cell? A. A timer B. An anode C. A cathode D. An electrolyte

A. A timer

Which type of widely used battery is not rechargeable? A. Zinc-manganese alkaline B. Lithium-ion C .Lead-acid (storage batteries) D. Nickel-cadmium (NiCad)

A. Zinc-manganese alkaline

Chemical energy is converted directly into electrical energy in A. a galvanic cell. B. an electrical power plant. C. an electrolytic cell. D. an automobile's engine.

A. a galvanic cell.

A major advantage of a fuel cell over a standard battery is that A. as long as oxygen and fuel are supplied, a fuel cell will not run down like a battery will. B. a fuel cell generates electricity without the need for an oxidation-reduction reaction. C. a fuel cell is 100 percent efficient at generating electricity, whereas a battery is less than 1 percent efficient. D. as it generates electricity, a fuel cell produces more fuel than it us

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

As fuel cells become more widely accepted and are used more, we will A. become less dependent on electrical energy. B. become more dependent on fossil fuels and less dependent on renewable resources for power generation. C. be able to generate electricity in places where we cannot now do so. D. use coal as our primary energy sour

C. be able to generate electricity in places where we cannot now do so.

How do the interactions that are broken in water when it is boiled compare with those broken when water is electrolyzed? A. Boiling water breaks intermolecular attractions and electrolysis breaks covalent bonds B. Boiling water breaks covalent bonds and electrolysis breaks intermolecular attractions C. Boiling water and electrolysis of water break covalent bonds D. Boiling water and electrolysis of water break intermolecular forces

A. Boiling water breaks intermolecular attractions and electrolysis breaks covalent bonds

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? A. Liquefy hydrogen under pressure and store it much as we do with liquefied natural gas today B. Absorb hydrogen onto activated charcoal; then heat the mixture to release the hydrogen C. Store it in the form of ionic metal hydrides, such as LiH, which release hydrogen gas when they react with water D. Encapsulate hydrogen molecules in fullerene molecules (large, carbon-based molecules that can act like cages) that may be heated later to release the hydrogen

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

Which of the following statements is not true about PEM fuel cells? A. PEM fuel cells rely on inexpensive catalysts B. PEM fuels cells are cleaner than gasoline powered vehicles C. PEM fuel cells have safe and efficient fuel storage D. PEM fuel cells have limited driving rang

A. PEM fuel cells rely on inexpensive catalysts

In general, a modern hybrid vehicle is less polluting than a standard vehicle because it runs on both a A. gasoline engine and an electric motor run by a rechargeable battery. B. gasoline engine and a fuel cell. C. fuel cell and an electric motor run by a rechargeable battery. D. gasoline engine and a cleaner diesel engine

A. gasoline engine and an electric motor run by a rechargeable battery.

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=O = 498 kJ/mol. A. -249 kJ B. +249 kJ C. -436 kJ D. +436 kJ

B. +249 kJ

Which type of battery is best for use in heart (cardiac) pacemakers? A. Alkaline B. Lithium-iodine C. Mercury D. Nickel-cadmium

B. Lithium-iodine

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? A. Mercury has become far too expensive to use in batteries B. Mercury is poisonous and difficult to dispose of C. These batteries cannot generate enough current for any modern devices D. Though they may be made very small, they are far too heavy to use in most applications

B. Mercury is poisonous and difficult to dispose of

Why can the lead-acid batteries used in cars generate electricity for several years before running down? A. A lead-acid battery is so large that it holds large quantities of the chemicals whose electrochemical interaction creates the electricity B. The mechanical motion of the engine drives an alternator that generates electricity to recharge the battery C. These batteries are used only to generate the electricity that makes the first spark plug "spark." Therefore, they are hardly used at all when a car is started, and never when it is driven D. The electrons they generate, not the chemical components, provide almost all of the electr

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

Which is an oxidation half-reaction? A. 2 H2+ O22 H2O B. Zn Zn2++ 2 e C. 2 HCl + Ba(OH)22 H2O + BaCl2 D. Cl2+ 2 e 2 Cl

B. Zn Zn2++ 2 e ̄ ̄

The opposite of a galvanic cell is A. a battery. B. an electrolytic cell. C. a fuel cell. D. a photovoltaic (solar) cell

B. an electrolytic cell.

For safety and other practical reasons, the most logical use for hydrogen as a fuel in the near future is A. in an electric power plant. B. in a fuel cell. C. for running an automobile. D. for nuclear fusion

B. in a fuel cell.

In a fuel cell, A. there is oxidation, but no reduction. B. reduction takes place at the cathode. C. there is direct conversion of mechanical energy into electricity. D. a chemical reaction produces heat, which then produces electricity

B. reduction takes place at the cathode.

Electrolysis is a process that A. produces an electrical current while decomposing water into hydrogen gas and oxygen gas. B. requires an electrical current to decompose water into hydrogen gas and oxygen gas. C. produces heat energy while decomposing water into hydrogen gas and oxygen gas. D. requires heat energy to decompose water into hydrogen gas and oxygen gas

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

How does using hydrogen as the fuel in an electric power plant compare with using hydrogen as the fuel in a fuel cell? A. H2 used as a fuel in a power plant must be more pure than the H2 used in a fuel cell B. Burning H2 in a power plant produces many more pollutants than using H2 in a fuel cell C. A fuel cell using hydrogen operates at a higher overall efficiency than would a power plant burning hydrogen as a fuel D. Using H2 in a fuel cell generates far more heat than burning it in a power plan

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

Which type of battery is widely used to store the excess energy generated by windmill farms and solar panels? A. Alkaline B. Lithium ion C. Lead acid D. Nickel-metal hydrid

C. Lead acid

At present, it will be difficult and perhaps inappropriate to develop an economy based on burning hydrogen rather than natural gas or gasoline because A. hydrogen is a dirty fuel. Burning hydrogen produces significantly more pollutants than burning natural gas or gasoline. B. hydrogen is not anefficient fuel. Per gram, hydrogen has about the lowest heat of combustion of any known substance, much lower than natural gas or gasoline. C. although hydrogen is abundant, pure hydrogen is not found naturally on earth. Hydrogen is difficult or expensive to isolate and collect. D. being such a light element, hydrogen will not flow through pipelines the way natural gas or gasoline do. Hydrogen cannot easily be delivered from where it is produced to the places where it is needed.

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

What condition must be met for a battery to be rechargeable? A. Either its anode or its cathode must generate a gas as a result of the electrochemical reaction B. It must generate electricity via an acid-base reaction rather than via an oxidation-reduction reaction C. The battery must be open to the outside so that it can vent any internal pressure that builds up from gases within it D. The electrochemical reaction of the battery must be reversible

D. The electrochemical reaction of the battery must be reversible

Batteries must be used in addition to solar cells when generating household electricity because A. solar cells can generate electricity only via the output of a battery. B. solar cells can generate only a small fraction of the total energy needed by a household at any one time. C. solar cells generate so much electricity that they will overheat if they cannot transfer the excess electricity somewhere to dissipate the extra heat. D. batteries must store and then supply the energy when sunlight is not avail

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

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 A. alkaline. B. lead acid. C. nickel-cadmium. D. nickel-metal hydride

D. nickel-metal hydride

During the chemical reaction in an electrochemical cell, A. a substance is oxidized and gains electrons. B. electrons travel from the cathode to the anode. C. oxidation takes place alone, without an accompanying reduction. D. oxidation occurs at the anode

D. oxidation occurs at the anode