Chapter 20:
Chemical Reactions and Energy
Practice Test
1.
Burning 1.00 g of a subtance with a molar mass of 42.0 g/mol raises the temperature of 100.0 g of water from 17.2
o
C to 47.2
o
C. What is the heat of combustion of the substance?
a.
-890 kJ/mol
b.
422 kJ/mol
c.
-527 kJ/mol
d.
-2.71 kJ/mol
Hint
2.
Plants appear green because their leaves _____________.
a.
reflect UV light
b.
reflect green and yellow light
c.
absorb green and yellow light
d.
reflect red and blue light
Hint
3.
Most of the reactions that occur during photosynthesis are _______________.
a.
thermoneutral
b.
exothermic
c.
endothermic
d.
double replacement
Hint
4.
If C
w
equals 4.184 J/(gx
o
C), how much heat does 235 g of water gain when its temperature rises from 20.4
o
C to 39.6
o
C?
a.
1.27 × 10
6
J
b.
18.9 kJ
c.
6,630 J
d.
0.438 kJ
Hint
5.
An exothermic reaction is one that __________.
a. produces smoke
b. absorbs heat
c. neither releases nor absorbs heat
d. releases heat
Hint
6.
This high-energy compound is formed during the light reactions of photosynthesis.
a.
carbon dioxide
b.
ATP
c.
glucose
d.
sucrose
Hint
7.
A reaction is always spontaneous in the forward direction when its ________________.
a.
energy decreases and entropy decreases
b.
energy decreases and entropy decreases
c.
energy decreases and entropy increases
d.
energy increases and entropy increases
Hint
8.
This substance provides the carbon and oxygen for the sugars produced by photosynthesis.
a.
ethanol
b.
formaldehyde
c.
carbon dioxide
d.
methane
Hint
9.
In photosynthesis, ________________ are formed.
a.
glucose and oxygen
b.
sucrose and water
c.
fructose and nitrogen
d.
glucose and carbon dioxide
Hint
10.
The maximum energy reached during a reaction's uncatalyzed pathway is ______________ the maximum energy reached during its catalyzed pathway.
a.
slightly less than
b.
equal to
c.
much less than
d.
greater than
Hint
11.
A system's ____________ describes its degree of disorder.
a.
enthalpy
b.
volume
c.
entropy
d.
energy
Hint
12.
An exothermic reaction has a ______________
H.
a.
zero
b.
negative
c.
positive
d.
high
Hint
13.
Oil and natural gas are called _____________.
a.
esters
b.
fossil fuels
c.
petroleum
d.
polymers
Hint
14.
An instant cold pack utilizes an _____________________ reaction.
a.
exothermic synthesis
b.
endothermic dissolution
c.
exothermic combustion
d.
endothermic combustion
Hint
15.
A coal-fired power plant converts ___________________.
a.
chemical energy to electricity
b.
electricity to wind energy
c.
geothermal energy to electricity
d.
kinetic energy to potential energy
Hint
16.
The low entropy of living things is maintained partially by ____________.
a.
an increase in the entropy of the surroundings
b.
a decrease in the entropy of the surroundings
c.
an increase in the energy of the living things
d.
a decrease in the energy of the universe
Hint
17.
The _______________ in photosynthetic bacteria is/are found on membranes spread throughout the cells.
a.
Calories
b.
chlorophyll
c.
grana
d.
rhizomes
Hint
18.
Both exothermic and endothermic reactions require ________________.
a.
activation energy
b.
gaseous reactants
c.
solid products
d.
precipitation
Hint
19.
Any time energy is produced or is converted from one form to another, some is lost as _________.
a.
heat
b.
hydrogen and oxygen
c.
temperature
d.
mass
Hint
20.
One Calorie equals _____________.
a.
one joule
b.
one calorie
c.
one BTU
d.
one kilocalorie
Hint
