24) The value of ΔH° for the decomposition of gaseous sulfur dioxide to solid elemental sulfur and
gaseous oxygen,
SO2 (g) → S (s,rhombic) + O2 (g)
is ________ kJ/mol.
A) 0.0
B) +135.0
C) -135.90
D) -269.9
E) +269.9
25) The value of ΔH° for the formation of POCl3 from its constituent elements,
P2 (g) + O2 (g) + 3Cl2 (g) → 2POCl3 (g)
is ________ kJ/mol.
A) -1228.7
B) -397.7
C) -686.5
D) +1228.7
E) +686.5
26) The value of ΔH° for the decomposition of POCl3 into its constituent elements,
2POCl3 (g) → P2 (g) + O2 (g) + 3Cl2 (g)
is ________ kJ/mol.
A) -1228.7
B) +1228.7
C) -940.1
D) +940.1
E) 0.00
27) The value of ΔH° for the formation of phosphorous trichloride from its constituent elements,
P2 (g) + 3Cl2 (g) → 2PCl3 (g)
is ________ kJ/mol
A) -288.1
B) +432.4
C) -720.5
D) +720.5
E) -432.4
28) The value of ΔH° for the decomposition of phosphorous trichloride into its constituent elements,
2PCl3 (g) → P2 (g) + 3Cl2 (g)
is ________ kJ/mol.
A) +576.2
B) -288.1
C) +720.5
D) +288.1
E) -720.5
29) The value of ΔH° for the formation of calcium chloride from its constituent elements,
Ca (s) + Cl2 (g) → CaCl2 (s)
is ________ kJ/mol.
A) 0.00
B) -397.9
C) +397.9
D) -795.8
E) +795.8
30) The value of ΔH° for the decomposition of calcium chloride into its constituent elements,
CaCl2 (s) → Ca (s) + Cl2 (g)
is ________ kJ/mol.
A) 0.00
B) -397.9
C) +397.9
D) -795.8
E) +795.8
31) 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.
A) +740.8
B) -370.4
C) +370.4
D) -740.8
E) +185.2
32) The value of ΔG° at 25 °C for the oxidation of solid elemental sulfur to gaseous sulfur dioxide,
S (s, rhombic) + O2(g) → SO2 (g)
is ________ kJ/mol.
A) +395.2
B) +269.9
C) -269.9
D) +300.4
E) -300.4
24
33) The value of ΔG° at 25 °C for the decomposition of gaseous sulfur trioxide to solid elemental sulfur
and gaseous oxygen,
2SO3 (g) → 2S (s, rhombic) + 3O2 (g)
is ________ kJ/mol.
A) +740.8
B) -370.4
C) +370.4
D) -740.8
E) +185.2
34) The value of ΔG° at 25 °C for the decomposition of gaseous sulfur dioxide to solid elemental sulfur
and gaseous oxygen,
SO2 (g) → S (s, rhombic) + O2 (g)
is ________ kJ/mol.
A) +395.2
B) +269.9
C) -269.9
D) +300.4
E) -300.4
35) The value of ΔG° at 25 °C for the formation of POCl3 from its constituent elements,
P2 (g) + O2 (g) + 3Cl2 (g) → 2POCl3 (g)
is ________ kJ/mol.
A) -1108.7
B) +1108.7
C) -606.2
D) +606.2
E) -1,005
36) The value of ΔG° at 25 °C for the decomposition of POCl3 into its constituent elements,
2POCl3 (g) → P2 (g) + O2 (g) + 3Cl2 (g)
is ________ kJ/mol.
A) -1108.7
B) +1108.7
C) -606.2
D) +606.2
E) -1,005
37) The value of ΔG° at 25 °C for the formation of phosphorous trichloride from its constituent elements,
P2 (g) + 3Cl2 (g) → 2PCl3 (g)
is ________ kJ/mol.
A) -539.2
B) +539.2
C) -642.9
D) +642.9
E) -373.3
38) The value of ΔG° at 25 °C for the decomposition of phosphorous trichloride into its constituent
elements,
2PCl3 (g) → P2 (g) + 3Cl2 (g)
is ________ kJ/mol.
A) -539.2
B) +539.2
C) -642.9
D) +642.9
E) -373.3
39) The value of ΔG° at 25 °C for the formation of calcium chloride from its constituent elements,
Ca (s) + Cl2 (g) → CaCl2 (s)
is ________ kJ/mol.
A) -795.8
B) +795.8
C) +763.7
D) +748.1
E) -748.1
40) The value of ΔG° at 25 °C for the decomposition of calcium chloride into its constituent elements,
CaCl2 (s) → Ca (s) + Cl2 (g)
is ________ kJ/mol.
A) -795.8
B) +795.8
C) +763.7
D) +748.1
E) -748.1
41) The value of ΔG° at 373 K for the oxidation of solid elemental sulfur to gaseous sulfur dioxide,
S (s, rhombic) + O2 (g) → SO2 (g)
is ________ kJ/mol. At 298 K, ΔH° for this reaction is –269.9 kJ/mol, and ΔS° is +11.6 J/K.
A) -300.4
B) +300.4
C) -4,597
D) +4,597
E) -274.2
27
42) The value of ΔG° at 25 °C for the following reaction:
C2H4 (g) + H2 (g) → C2H6 (g)
is ________ kJ/mol. At 298 K, ΔH° for this reaction is –137.5 kJ/mol, and ΔS° is +120.5 J/K.
A) -35800
B) -173.4
C) 35800
D) -101.7
E) -274.2
43) Given the thermodynamic data in the table below, calculate the equilibrium constant (at 298 K) for the
reaction:
2 SO2 (g) + O2 (g) 2 SO3 (g)
A) 2.40 × 1024
B) 1.06
C) 1.95
D) 3.82 × 1023
E) More data are needed.
44) 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.
A) 0.292
B) -4.20
C) 0.320
D) -1.13
E) More information is needed.
45) The value of ΔG° for a reaction conducted at 25 °C is 2.8 kJ/mol. The equilibrium constant for a
reaction is ________ at this temperature.
A) 1.13
B) -4.2
C) 0.32
D) -1.13
E) More information is needed.
46) Consider the reaction:
NH3 (g) + HCl (g) → NH4Cl (s)
Given the following table of thermodynamic data at 298 K:
The value of K for the reaction at 25 °C is ________.
A) 150
B) 9.3 × 1015
C) 8.4 × 104
D) 1.1 × 10–16
E) 1.4 × 108
47) Consider the reaction:
FeO (s) + Fe (s) + O2(g) → Fe2O3 (s)
Given the following table of thermodynamic data at 298 K:
The value K for the reaction at 25 °C is ________.
A) 370
B) 5.9 × 104
C) 3.8 × 10–14
D) 7.1 × 1085
E) 8.1 × 1019
48) Consider the reaction:
Ag+ (aq) + Cl– (aq) → AgCl (s)
Given the following table of thermodynamic data at 298 K:
The value of K for the reaction at 25 °C is ________.
A) 810
B) 5.3 × 109
C) 1.8 × 104
D) 3.7 × 1010
E) 1.9 × 10–10
19.3 Algorithmic Questions
1) The normal boiling point of methanol is 64.7 °C and the molar enthalpy of vaporization if 71.8 kJ/mol.
The value of ΔS when 1.75 mol of CH3OH (l) vaporizes at 64.7 °C is ________ J/K.
A) 0.372
B) 4.24 × 107
C) 372
D) 1.94 × 103
E) 1.94
2) 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 24.7 grams of steam at 1 atm condenses to a
liquid at the normal boiling point?
A) 88.8
B) -88.8
C) -150
D) 373
E) -40.7
3) The normal boiling point of C2Cl3F3 is 47.6 °C and its molar enthalpy of vaporization is 27.49 kJ/mol.
What is the change in entropy in the system in J/K when 28.6 grams of C2Cl3F3 vaporizes to a gas at the
normal boiling point?
A) -13.1
B) -4.19
C) 4.19
D) 13.1
E) 27.5
4) The normal boiling point of ethanol (C2H5OH) is 78.3 °C and its molar enthalpy of vaporization is
38.56 kJ/mol. What is the change in entropy in the system in J/K when 112.2 grams of ethanol at 1 atm
condenses to a liquid at the normal boiling point?
A) 382
B) 1199
C) -382
D) –1199
E) -267
5) Which one of the following processes produces a decrease in the entropy of the system?
A) freezing of Fe(l) into Fe(s)
B) evaporation of liquid ethanol into gaseous ethanol
C) dissolution of LiOH(s) in water
D) melting ice to form water
E) mixing of two gases into one container
6) ΔS is negative for the reaction ________.
A) Sr(NO3)2 (aq) + 2LiOH (aq) → Sr(OH)2 (s) + 2LiNO3 (aq)
B) 2H2O (g) → 2H2 (g) + O2 (g)
C) CH3OH (l) → CH3OH (g)
D) LiOH (aq) → Li+ (aq) + OH– (aq)
E) C6H12O6 (s) → 6C (s) + 6H2 (g) + 3O2 (g)
7) Of the following, the entropy of ________ is the largest.
A) HI (g)
B) HBr (g)
C) HCl (g)
D) HCl (s)
E) HCl (l)