Chapter 16:
Energy and Chemical Change
Practice Test
1.
How much heat is absorbed in the complete reaction of 3.00 grams of SiO
2
with excess carbon in the reaction below?
Δ
H
° for the reaction is +624.7 kJ.
SiO
2
(g) + 3C(s) → SiC(s) + 2CO(g)
a.
31.2 kJ
b.
1.13 × 10
5
kJv
c.
366 kJ
d.
5.06 kJ
Hint
2.
Calculate the Δ
G
° for the reaction below.
2C
2
H
2
(g) + 5O
2
(g) → 4CO
2
(g) + 2H
2
O(l)
Δ
G
° (kJ/mol) 209.2 0 -394.4 -237.2
a.
-1409 kJ
b.
-1643 kJ
c.
-2470 kJ
d.
-2599 kJ
Hint
3.
A body in motion possesses kinetic energy because of its __________.
a.
position
b.
motion
c.
inertia
d.
composition
Hint
4.
Calculate the amount of heat absorbed by 10.0 grams of ice at -15.0°C as it is converted to liquid water at 50.0°C. The specific heat of H
2
O(s) = 2.09 J/(g•°C). The specific heat of H
2
O(l) = 4.18 J/(g•°C). The heat of fusion is 333 J/g.
a.
2.83 kJ
b.
0.676 kJ
c.
0.170 kJ
d.
5.73 kJ
Hint
5.
The same amount of heat is added to a 10-g sample of each of the following metals. If each metal is initially at 20.0°C, which metal will reach the highest temperature?
a.
copper 0.385 J/(g•°C)
b.
gold 0.129 J/(g•°C)
c.
calcium 0.653 J/(g•°C)
d.
beryllium 1.82 J/(g•°C)
Hint
6.
Calculate the entropy change for the reaction below.
N
2
(g) + 3H
2
(g) → 2NH
3
(g)
S
° (J/mol•K) 191.5 130.6 192.3
a.
-198.7 J/K
b.
-129.7 J/K
c.
76.32 J/K
d.
303.2 J/K
Hint
7.
Chemical reactions and physical changes that absorb energy from their surroundings are __________.
a.
endothermic
b.
mesothermic
c.
exothermic
d.
isothermic
Hint
8.
For the reaction below, the enthalpy change is +624.7 kJ. How would you classify this reaction?
SiO
2
(g) + 3C(s) → SiC(s) + 2CO(g)
a.
exothermic reaction, heat is lost from the system
b.
endothermic reaction, heat is gained by the system
c.
exothermic reaction, heat is gained by the system
d.
endothermic reaction, heat is lost from the system
Hint
9.
How much heat energy is liberated when 11.0 grams of manganese is used in the formation of Mn
2
O
3
?
Δ
H
f
° for Mn
2
O
3
is -962.3 kJ/mol
a.
460 kJ
b.
289 kJ
c.
192 kJ
d.
96.3 kJ
Hint
10.
Given the following information,
SO
3
(g) + H
2
O(l) → H
2
SO
4
(l) Δ
H
° = -133 kJ
Pb(s) + PbO
2
(s) + 2H
2
SO
4
(l) → 2PbSO
4
(s) + 2H
2
O(l) Δ
H
° = -509 kJ
calculate the Δ
H
° for the reaction below.
Pb(s) + PbO
2
(s) + 2SO
3
(g) → 2PbSO
4
(s)
a.
-376 kJ
b.
-642 kJ
c.
+376 kJ
d.
-775 kJ
Hint
11.
If 5.0 grams of copper cools from 35.0°C to 22.6°C and loses 23.6 joules of heat, what is the specific heat of copper?
a.
0.62 J/(g•°C)
b.
0.38 J/(g•°C)
c.
0.076 J/(g•°C)
d.
3.8 × 10
2
J/(g•°C)
Hint
12.
From the following data,
H
2
(g) + Cl
2
(g) → 2HCl(g) Δ
H
°v = -185 kJ
2H
2
(g) + O
2
(g) → 2H
2
O(g) Δ
H
° = -483.7 kJ
calculate Δ
H
° for the following reaction.
4HCl(g) + O
2
(g) → 2Cl
2
(g) + 2H
2
O(g)
a.
+299 kJ
b.
-114 kJ
c.
+114 kJ
d.
-299 kJ
Hint
13.
Calculate the enthalpy for the reaction below
2ZnS(s) + 3O
2
(g) → 2ZnO(s) + 2SO
2
(g)
Δ
H
f
° (kJ/mol) -206.0 0 -348.3 -296.8
a.
-270.6 kJ
b.
+270.6 kJ
c.
-878.2 kJ
d.
+878.2 kJ
Hint
14.
Which of the following substances has an enthalpy value of 0 at 298 K and 1 atmosphere of pressure?
a.
HCl(aq)
b.
NaOH(s)
c.
Na(s)
d.
CO
2
(g)
Hint
15.
At one atmosphere pressure and the melting point of a substance, which statement is true about this general equation?
solid 3 liquid
a.
Δ
H
= 0 for the process
b.
Δ
G
= 0 for the process
c.
Both Δ
H
and Δ
S
= 0 for the process
d.
Δ
S
= 0 for the process
Hint
16.
Calculate Δ
H
° for the following reaction.
Fe
3
O
4
(s) + CO(g) → 3FeO(s) + CO
2
(g)
Δ
H
° (kJ/mol) -1118 -110.5 -272 -393.5
a.
-263 kJ
b.
54 kJ
c.
19 kJ
d.
-50 kJ
Hint
17.
A process can never be spontaneous when it is _________.
a.
exothermic, and there is an increase in disorder
b.
endothermic, and there is an increase in disorder
c.
exothermic, and there is an increase in disorder
d.
endothermic, and there is a decrease in disorder
Hint
18.
In the chemical reaction between aqueous solutions of hydrochloric acid (HCl) and sodium hydroxide (NaOH), what is the chemical system?
a.
aqueous HCl and NaOH
b.
HCl + NaOH → NaCl + H
2
O
c.
HCl and water
d.
NaOH and water
Hint
19.
Which of the following occurs with an increase in entropy?
a.
twenty nickels taken from a box and arranged tails up on a table
b.
the reaction PCl
3
(g) + Cl
2
(g) → PCl
5
(g)
c.
precipitation of silver chloride from a solution of silver ions and chloride ions
d.
evaporation of carbon tetrachloride
Hint
20.
Which of the following processes occurs with a decrease in entropy?
a.
boiling water
b.
freezing of water
c.
sublimation of dry ice
d.
dissolving salt in water
Hint
