chapter 11 Chemical Reactions

Question 1

The scientist who discovered oxygen was

a. Joseph Priestly
b. Johann Becher
c. Fritz Harber
d. Antoine Lavoisier

Answer 1

A. Joseph Pristly

Question 2

According to the phlogiston hypothesis

a. all substances that can be burned contain phlogiston
b. as a substance burns, the phlogiston it contains is turned into ask or powder
c. metals are considered to be solid forms of pure phlogiston
d. phlogiston must be present in air before a substance can be burned

Answer 2

A. all substances that can be burned contain phlogitson

Question 3

The phlogiston hypothesis was overthrown as a result of the experiment conducted by

a. Georg Stahl
b. Joseph Priestly
c. Antoine Lavoisier
d. Johann Becher

Answer 3

C. Antoine Lavoisier

Question 4

When heated in the presence of air, tin turns into white powder. The substances in the air that combines with the tin to form the white powder is

a. nitrogen
b. hydrogen
c. carbon dioxide
d. oxygen

Answer 4

D. oxygen

Question 5

in the preceding question, the tine has been

a. activated
b. oxidized
c. tempered
d. alloyed

Answer 5

B. oxidized

Question 6

The burning of coal, in which energy is liberated, is a(n)

a. exothermic reaction
b. endothermic reaction
c. catalytic reaction
d. equilibrium reaction

Answer 6

A. exothermic reaction

Question 7

A compound is usually relatively stable if

a. its decomposition is weakly exothermic
b. it liberates energy when decomposed
c. a great deal of energy is needed to decompose the compound
d. the PE of its electrons is high

Answer 7

C. a great deal of energy is needed to decompose the compund

Question 8

a good fuel is
a strong exothermic
b. cheap and abundant 
c. easy to transport
d. all of the above

Answer 8

D. all of the above

Question 9

a catalytic converter works by

a. trapping harmful gasses so they are not part of the exhaust
b. increasing the reactions temperature to increase the rate of combustion
c. increasing the concentration of exhaust gas to promote more complete combustion
d. promoting reaction the promote polluting gases into harmless ones by the action of certain metals

Answer 9

D. Promoting reaction the promote polluting gases into harmless ones by the action of certain metals

Question 10

Hydrogen is nit widely used as a fuel at present because

a. its combustion products are extremely “dirty”
b. it is currently to expensive for ordinary purposes
c. it has an extremely low heat of combustion
d. it is scarce

Answer 10

B. it is currently to expensive for ordinary purposes

Question 11

A disadvantage of the use of syngas is
A. the scarcity of the raw materials needed to produce syngas
B. its high sulfur content
C. problems related to transport and storage
D. its carbon monoxide content

Answer 11

D. its carbon monoxide content

Question 12

Which one of the following elements plays a major role in the formation of acid rain?
A. carbon
B. sulfur
C. chlorine
D. boron

Answer 12

B. sulfur

Question 13

the rate of a chemical reaction can be increased by
A. lowering the temperature of the reaction
B. reducing the concentrations of the reactants
C increasing the surface are of a solid reactant
D. lowering the activation energy

Answer 13

C. increasing the surface are a solid reactant

Question 14

Catalysts used by living organism to regulate their chemical processes are called
A. hormones
B. steroids
C. enzymes
D. lipids

Answer 14

C. enzymes

Question 15

a disadvantage is using fuel cells to power automobiles is
A. their relatively short life span
B. a high weight to electrical power ratio
C. the release of large amounts of CO2 into the atmosphere
D. the safe storage of hydrogen fuel needed for a moderately long trip

Answer 15

D. the safe storage of hydrogen fuel needed for a moderately long trip

Question 16

T/F

if a given chemical reaction is exothermic, the revise reaction will be endothermic

Answer 16

True

Question 17

T/F
The amount of heat liberated by an exothermic reaction is the same as the amount of heat absorbed by the reverse endothermic reaction.

Answer 17

True

Question 18

T/F

Chemical energy is really electron potential energy

Answer 18

True

Question 19

T/F

During an exothermic reaction, the original PE of the electron of the reating atoms is increased

Answer 19

False the original PE of the electrons of the reacting atoms is liberates and thereby reduced.

Question 20

T/F

Reaction rates increases with temperature mainly because the total number of molecular collisions increases.

Answer 20

False

Number of ACTIVATED molecules increases

Question 21

T/F

In an oxidation-reduction reaction, the oxidation of an element is always accompanied by the reduction of another.

Answer 21

True

Question 22

T/F

most acid rain is caused by the emissions of automibles

Answer 22

False

Most acid rain is caused by the EMISSION FROM COAL-BURNING POWER PLANTS AND METAL REFINERIES

Question 23

T/F

Using fossil fuels to produce hydrogen will help to reduce pollution and conserve resources

Answer 23

False

using fossil fuels to produce hydrogen will do NOTHING to reduce pollution and conserve resources.

Question 24

Rapid oxidation is called-

Answer 24

Combustion

Question 25

–number us equal to the number of atoms per mole of any element

Answer 25

Avogadro’s

Question 26

a(n) – is a compound of oxygen and another element

Answer 26

oxide

Question 27

– chemical reactions liberate energy; – reactions absorb energy

Answer 27

Exothermic enothermic

Question 28

The energy needed to start a chemical reaction is called – energy

Answer 28

activation

Question 29

–, a mixture of various hydrocarbons, is the source of most liquid fuels

Answer 29

petroleuim

Question 30

A(n)– is a substance that can change the rate of a chemical reaction without itself being permanently changed

Answer 30

catalyst

Question 31

In an oxidation-reaction reaction, – involves the loss of electrons and – involves the gain electron

Answer 31

oxidation reduction

Question 32

In the process of –, free elements are liberated from a liquid by the passage of an electric current

Answer 32

electroysis

Question 33

Dry-cell batteries, lithium ion batteries, and furl cells are all examples of – cells

Answer 33

electrochemical

Question 34

The current in the molten NaCl consists of
A. moving Na and Cl atoms
B. Moving Na+ and Cl- ions
C. Moving Cl- ions only
D. moving electrons

Answer 34

B. moving Na+ and Cl- ions