Exam 4 Review

Would like to ensure that I have to right answers to the practice problems for exam review. Thanks.

Question 1
Which one of the following is NOT one of the five gaseous components in highest concentration in the atmosphere?

CH4
CO2
N2
Ar
O2

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Question 2
Which region of the atmosphere contains the ozone layer?

thermosphere
mesosphere
stratosphere
troposphere

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Question 3
Which choice lists two health effects expected from the depletion of the ozone layer?

asthma
lung cancer
skin cancer
cataracts
emphysema
1 and 5
2 and 3
3 and 5
3 and 4
4 and 5

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Question 4
The compound CFCl3 is used as a(n) ______.

enzyme
anesthetic
gaseous fuel
refrigerant
CFC replacement

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Question 5
Acid rain is less of a threat to lakes and streams in areas where the rock is limestone (CaCO3). Which of the following is the equation for neutralization of acid by limestone?

CaCO3 + OH- CaOH + CO2
CaCO3 + 2H3O+ Ca2+ + CO2 + 3H2O
CaCO3 + H3O Ca + CO2 + H2O
CaCO3 + OH- Ca2+ + CO2 + H2O
CaCO3 + 2H3O+ Ca2+ + CO2 + 2H2O

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Question 6
Peroxyacetyl nitrate, called PAN for short, is a powerful lachrymator. A lachrymator is a(n) ________.

greenhouse gas
product of incomplete combustion
agent that induces drowsiness
tear producer
cancer causing agent

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Question 7
Which of the following species has the highest entropy (So) at 25oC?

CH3OH(l)
CO(g)
MgCO3(s)
H2O(l)
Ni(s)

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Question 8
Which response includes all the following processes that are accompanied by an increase in entropy?

2SO2(g) + O2(g) SO3(g)
H2O(l) H2O(s)
Br2(l) Br2(g)
H2O2(l) H2O(l) + ½O2(g)
1, 2, 3, 4
1, 2
2, 3, 4
3, 4
1, 4

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Question 9
Arrange the following reactions according to increasing S (lowest highest).

H2O(g) H2O(l)
2NO(g) N2(g) + O2(g)
MgCO3(s) MgO(s) + CO2(g)
1 < 2 < 3
2 < 3 < 1
3 < 2 < 1
2 < 1 < 3
1 < 3 < 2

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Question 10
Arrange the following reactions according to increasing S.

CH4(g) + H2O(g) CO(g) + 3H2(g)
C(s) + O2(g) CO2(g)
H2O2(l) H2O(l) + ½O2(g)
3 < 2 < 1
2 < 1 < 3
2 < 3 < 1
3 < 1 < 2
1 < 3 < 2

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Question 11

Given the following absolute entropies, determine So for the reaction

SO3(g) + H2O(l) H2SO4(l)

So (J/K mol)
SO3 256.2
H2O 69.9
H2SO4 156.9

So = 169.3 J/K
So = 1343.2 J/K
So = -169.3 J/K
So = -29.4 J/K
So = 29.4 J/K

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Question 12
A negative sign for G indicates that, at constant T and P, ________.

the reaction is exothermic
the reaction is endothermic
the reaction is fast
the reaction is spontaneous
S must be > 0

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Question 13

Given the following free energies of formation, calculate Go for the reaction

3NO2(g) + H2O(l) 2HNO3(l) + NO(g)

G (kJ/mol)
H2O(l) -237.2
HNO3(l) -79.9
NO(g) 86.7
NO2(g) 51.8

8.7 kJ
192 kJ
-414 kJ
-192 kJ
-155 kJ

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Question 14
The element oxygen was prepared by Joseph Priestley in 1774 by heating mercury(II) oxide.

HgO(s) Hg(l) + ½O2(g) Ho = 90.84 kJ

Use the data given below to estimate the temperature at which this reaction will become spontaneous under standard state conditions.

So(Hg) = 76.02 J/K mol
So(O2) = 205.0 J/K mol
So(HgO) = 70.29 J/K mol

108 K
430 K
620 K
775 K
840 K

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Question 15
At 1500oC, the equilibrium constant is KP = 1.4 x 10-7 for the reaction

CO(g) + 2H2(g) CH3OH(g)

Calculate Go for this reaction at 1500oC.

105 kJ
1.07 kJ
-233 kJ
-105 kJ
233 kJ

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Question 16

Given the following free energies of formation, calculate KP for the reaction below at 298 K.

SO2(g) + NO2(g) SO3(g) + NO(g)

G (kJ/mol)
SO2(g) -300.4 kJ/mol
SO3(g) -370.4 kJ/mol
NO(g) 86.7 kJ/mol
NO2(g) 51.8 kJ/mol

6.99 x 10-7
5.71 x 10-8
14.2
475
1.43 x 106

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Question 17
Using tabulated values in the textbook, determine the equilibrium constant KP for the following reaction at 25oC.

N2(g) + 3H2(g) 2NH3(g)

1.5 x 10-6
6.6 x 105
8.28 x 10-2
2.60
13.4

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Question 18
Nitrosyl chloride (NOCl) decomposes at elevated temperatures according to the equation

2NOCL(g) 2NO(g) + Cl2(g)

Use the following information to calculate KP for this reaction at 227oC:

Ho = 81.2 kJ
So = 128 J/K

1.60 x 10-2
2.1 x 10-7
62.8
4.9 x 106
3.20 x 109

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Question 19
Determine the equilibrium constant (KP) for the following reaction at 25oC:

CO(g) + H2O(g) CO2(g) + H2(g) Go = -28.5 kJ

2.9 x 10-60
1.0 x 10-4
1.2
1.0 x 105
3.4 x 1059

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Question 20
A spontaneous endothermic reaction always ________.

causes the surroundings to get colder
bursts into flame
requires a spark to initiate it
releases heat to the surroundings