Question 1
Question
The first law of thermodynamics can be given as __________.
Answer
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A) ΔE = q + w
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B)
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C) for any spontaneous process, the entropy of the universe increases
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D) the entropy of a pure crystalline substance at absolute zero is zero
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E) ΔS = qrev/T at constant temperature
Question 2
Question
Of the following, only __________ is not a state function.
Question 3
Question
When a system is at equilibrium, __________.
Answer
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A) the reverse process is spontaneous but the forward process is not
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B) the forward and the reverse processes are both spontaneous
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C) the forward process is spontaneous but the reverse process is not
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D) the process is not spontaneous in either direction
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E) both forward and reverse processes have stopped
Question 4
Question
A reversible process is one that __________.
Answer
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A) can be reversed with no net change in either system or surroundings
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B) happens spontaneously
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C) is spontaneous in both directions
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D) must be carried out at low temperature
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E) must be carried out at high temperature
Question 5
Question
Which of the following statements is true?
Answer
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A) Processes that are spontaneous in one direction are spontaneous in the opposite direction.
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B) Processes are spontaneous because they occur at an observable rate.
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C) Spontaneity can depend on the temperature.
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D) All of the statements are true.
Question 6
Question
For an isothermal process, ΔS = __________.
Answer
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A) q
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B) qrev/T
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C) qrev
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D) Tqrev
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E) q + w
Question 7
Question
Which one of the following is always positive when a spontaneous process occurs?
Answer
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A) ΔSsystem
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B) ΔSsurroundings
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C) ΔSuniverse
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D) ΔHuniverse
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E) ΔHsurroundings
Question 8
Question
The second law of thermodynamics states that __________.
Answer
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A) ΔE = q + w
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B)
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C) for any spontaneous process, the entropy of the universe increases
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D) the entropy of a pure crystalline substance is zero at absolute zero
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E) ΔS = qrev/T at constant temperature
Question 9
Question
Which of the following statements is false?
Answer
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A) The change in entropy in a system depends on the initial and final states of the system and the path taken from one state to the other.
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B) Any irreversible process results in an overall increase in entropy.
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C) The total entropy of the universe increases in any spontaneous process.
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D) Entropy increases with the number of microstates of the system.
Question 10
Question
Which one of the following processes produces a decrease of the entropy of the system?
Answer
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A) dissolving sodium chloride in water
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B) sublimation of naphthalene
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C) dissolving oxygen in water
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D) boiling of alcohol
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E) explosion of nitroglycerine
Question 11
Question
Consider a pure crystalline solid that is heated from absolute zero to a temperature above the boiling point of the liquid. Which of the following processes produces the greatest increase in the entropy of the substance?
Answer
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A) melting the solid
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B) heating the liquid
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C) heating the gas
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D) heating the solid
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E) vaporizing the liquid
Question 12
Question
Which one of the following correctly indicates the relationship between the entropy of a system and the number of different arrangements, W, in the system?
Answer
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A) S = kW
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B) S = k/W
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C) S = W/k
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D) S = klnW
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E) S = Wk
Question 13
Question
ΔS is positive for the reaction __________.
Answer
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A) 2H2 (g) + O2 (g) → 2H2O (g)
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B) 2NO2 (g) → N2O4 (g)
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C) CO2 (g) → CO2 (s)
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D) BaF2 (s) → Ba2+ (aq) + 2F- (aq)
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E) 2Hg (l) + O2 (g) → 2HgO (s)
Question 14
Question
Which reaction produces an increase in the entropy of the system?
Answer
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A) Ag+ (aq) + Cl- (aq) → AgCl (s)
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B) CO2 (s) → CO2 (g)
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C) H2 (g) + Cl2 (g) → 2HCl (g)
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D) N2 (g) + 3H2 (g) → 2NH3 (g)
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E) H2O (l) → H2O (s)
Question 15
Question
Of the following, the entropy of __________ is the largest.
Answer
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A) HCl (l)
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B) HCl (s)
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C) HCl (g)
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D) HBr (g)
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E) HI (g)
Question 16
Question
Of the following, the entropy of gaseous __________ is the largest at 25°C and 1 atm.
Answer
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A) CH3OH
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B) C2H5OH
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C) C3H7OH
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D) CH4
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E) C4H10
Question 17
Question
For an isothermal process, the entropy change of the surroundings is given by the equation:
Answer
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A) ΔS = qsys T
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B) ΔS = -qsys T
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C) ΔS = q lnT
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D) ΔS = -q lnT
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E) ΔS = -qsys/T
Question 18
Question
The equilibrium position corresponds to which letter on the graph of G vs. f (course of reaction) below?
Question 19
Question
For the reaction
C2H6 (g) → C2H4 (g) + H2 (g)
ΔH° is + 137 kJ/mol and ΔS° is +120 J/K ∙ mol. This reaction is __________.
Answer
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A) spontaneous at all temperatures
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B) spontaneous only at high temperature
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C) spontaneous only at low temperature
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D) nonspontaneous at all temperatures
Question 20
Question
For the reaction
2C4H10 (g) + 13O2 (g) → 8CO2 (g) + 10H2O (g)
ΔH° is -125 kJ/mol and ΔS° is +253 J/K ∙ mol. This reaction is __________.
Answer
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A) spontaneous at all temperatures
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B) spontaneous only at high temperature
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C) spontaneous only at low temperature
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D) nonspontaneous at all temperatures
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E) unable to determine without more information
Question 21
Question
A reaction that is not spontaneous at low temperature can become spontaneous at high temperature if ΔH is __________ and ΔS is __________.
Answer
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A) +, +
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B) -, -
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C) +, -
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D) -, +
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E) +, 0
Question 22
Question
Given the following table of thermodynamic data, complete the following sentence. The vaporization of PCl3 (l) is __________.
Answer
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A) nonspontaneous at low temperature and spontaneous at high temperature
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B) spontaneous at low temperature and nonspontaneous at high temperature
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C) spontaneous at all temperatures
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D) nonspontaneous at all temperatures
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E) not enough information given to draw a conclusion
Question 23
Question
Consider the reaction:
Ag+ (aq) + Cl- (aq) → AgCl (s)
Given the following table of thermodynamic data, determine the temperature (in °C) above which the reaction is nonspontaneous under standard conditions.
Answer
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A) 1230 °C
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B) 150 °C
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C) 432 °C
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D) 133 °C
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E) 1640 °C
Question 24
Question
Consider the reaction:
NH3 (g) + HCl (g) → NH4Cl (s)
Given the following table of thermodynamic data,
determine the temperature (in °C) above which the reaction is nonspontaneous.
Question 25
Question
With thermodynamics, one cannot determine __________.
Answer
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A) the speed of a reaction
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B) the direction of a spontaneous reaction
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C) the extent of a reaction
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D) the value of the equilibrium constant
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E) the temperature at which a reaction will be spontaneous
Question 26
Question
If ΔG° for a reaction is greater than zero, then __________.
Question 27
Question
The value of ΔS° for the catalytic hydrogenation of ethene to ethane,
C2H4 (g) + H2(g) → C2H6 (g)
is __________ J/K∙ mol.
Answer
-
A) -101.9
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B) -120.5
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C) -232.5
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D) +112.0
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E) +101.9
Question 28
Question
The value of ΔS° for the oxidation of carbon to carbon dioxide,
C (s, graphite) + O2 (g) → CO2(g)
is __________ J/K∙ mol. The combustion of carbon, as in charcoal briquettes, in the presence of abundant oxygen produces carbon dioxide.
Answer
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A) +424.3
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B) +205.0
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C) -205.0
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D) -2.9
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E) +2.9
Question 29
Question
The value of ΔH° for the decomposition of gaseous sulfur trioxide to its component elements,
2SO3 (g) → 2S (s, rhombic) + 3O2 (g)
is __________ kJ/mol.
Answer
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A) +790.4
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B) -790.4
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C) +395.2
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D) -395.2
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E) +105.1
Question 30
Question
The value of ΔG° at 25 °C for the oxidation of solid elemental sulfur to gaseous sulfur trioxide,
2S (s, rhombic) + 3O2 (g) → 2SO3 (g)
is __________ kJ/mol.
Answer
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A) +740.8
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B) -370.4
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C) +370.4
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D) -740.8
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E) +185.2
Question 31
Question
Given the thermodynamic data in the table below, calculate the equilibrium constant (at 298 K) for the reaction:
2SO2 (g) + O2 (g) --> 2SO3 (g)
Answer
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A) 2.37 × 1024
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B) 1.06
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C) 1.95
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D) 3.82 × 1023
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E) More data are needed.
Question 32
Question
The value of ΔG° for a reaction conducted at 25°C is 3.05 kJ/mol. The equilibrium constant for a reaction is __________ at this temperature?
Question 33
Question
The normal boiling point of water is 100.0°C and its molar enthalpy of vaporization is 40.67 kJ/mol. What is the change in entropy in the system in J/K when 39.3 grams of steam at 1 atm condenses to a liquid at the normal boiling point?
Answer
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A) 88.8
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B) -88.8
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C) -238
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D) 373
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E) -40.7
Question 34
Question
The standard Gibbs free energy of formation of __________ is zero.
(a) H2O (l)
(b) O (g)
(c) I2 (s)
Answer
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A) (a) only
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B) (b) only
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C) (c) only
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D) (b) and (c)
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E) (a), (b), and (c)
Question 35
Question
The standard Gibbs free energy of formation of __________ is zero.
(a) H2O (l)
(b) Mg (s)
(c) Br2 (l)
Answer
-
A) (a) only
-
B) (b) only
-
C) (c) only
-
D) (b) and (c)
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E) (a), (b), and (c)
Question 36
Question
The standard Gibbs free energy of formation of __________ is zero.
(a) Si (s)
(b) F2 (g)
(c) Ni (s)
Answer
-
A) (a) only
-
B) (b) only
-
C) (c) only
-
D) (b) and (c)
-
E) (a), (b), and (c)
Question 37
Question
The value of ΔG° at 141.0°C for the formation of phosphorous trichloride from its constituent elements,
P2 (g) + 3Cl2 (g) → 2PCl3 (g)
is __________ kJ/mol. At 25.0°C for this reaction, ΔH° is -720.5 kJ/mol, ΔG° is -642.9 kJ/mol, and ΔS° is -263.7 J/K.
Answer
-
A) -612.3
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B) 3.65 × 104
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C) 1.08 × 105
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D) -683.3
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E) -829.7
Question 38
Question
For the reaction
C(s) + H2O(g) → CO(g) + H2(g)
ΔH° = 131.3 kJ/mol and ΔS° = 127.6 J/K ∙ mol at 298 K. At temperatures greater than __________°C this reaction is spontaneous under standard conditions.
Answer
-
A) 273
-
B) 325
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C) 552
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D) 756
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E) 1029
Question 39
Question
For a given reaction, ΔH = +35.5 kJ/mol and ΔS = +83.6 J/K-mol. The reaction is spontaneous __________. Assume that ΔH and ΔS do not vary with temperature.
Answer
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A) at T < 425 K
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B) at T > 425 K
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C) at all temperatures
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D) at T > 298 K
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E) at T < 298 K
Question 40
Question
In the Haber process, ammonia is synthesized from nitrogen and hydrogen:
N2 (g) + 3H2 (g) → 2NH3 (g)
ΔG° at 298 K for this reaction is -33.3 kJ/mol. The value of ΔG at 298 K for a reaction mixture that consists of 1.9 atm N2, 1.6 atm H2, and 0.65 atm NH3 is __________.
Answer
-
A) -1.8
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B) -3.86 × 103
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C) -7.25 × 103
-
D) -104.5
-
E) -40.5
Question 41
Question
Phosphorous and chlorine gases combine to produce phosphorous trichloride:
P2 (g) + 3Cl2 (g) → 2PCl3 (g)
ΔG° at 298 K for this reaction is -642.9 kJ/mol. The value of ΔG at 298 K for a reaction mixture that consists of 1.5 atm P2, 1.6 atm Cl2, and 0.65 atm PCl3 is __________.
Answer
-
A) -44.2
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B) -3.88 × 103
-
C) -7.28 × 103
-
D) -708.4
-
E) -649.5
Question 42
Question
15) The equilibrium constant for a reaction is 0.35 at 25°C. What is the value of ΔG° (kJ/mol) at this temperature?
Question 43
Question
A reversible change produces the maximum amount of ________ that can be achieved by the system on the surroundings.
Answer
-
A) Energy
-
B) Product
-
C) Reactant
-
D) Work
Question 44
Question
The melting of a substance at its melting point is an isothermal process.
Question 45
Question
The vaporization of a substance at its boiling point is an isothermal process
Question 46
Question
The entropy of a pure crystalline substance at 0°C is zero.
Question 47
Question
The more negative ΔG° is for a given reaction, the larger the value of the corresponding equilibrium constant, K.