CHEM 1332
SPRING 2004
THIRD EXAM - APRIL, 23rd – Version 1
1.
Which of the following mixtures would NOT be described as a buffer solution?
(A)
(C)
(E)
0.15 M NH4Cl and 0.25 M NH3
0.25 M HNO2 and 0.15 M KNO2
0.30 M NH3 and 0.15 M HCl
2.
Given that the Kb of NH3 is 1.8 x 10-5, calculate the pH of a solution that is made by mixing 40.0 mL of 0.25 M NH3 and 10.0 mL
of 0.45 M NH4Br.
(A)
4.4
3.
A buffer is required that has a pH of 4. Which of the following acid/base pairs would be the most suitable? You may need the
dissociation constants:
HCOOH
CH3COOH
H3AsO4
C5H5N
NH3
(B)
(B)
(D)
5.0
(C)
0.20 M NaOH and 0.40 M CH3COOH
0.25 M HNO3 and 0.15 M KNO3
8.7
(D)
9.0
(E)
9.6
Ka = 1.8 x 10-4
Ka = 1.8 x 10-5
Ka1 = 6.0 x 10-3, Ka2 = 1.1 x 10-7, Ka3 = 3 x 10-12
Ka = 1.7 x 10-9
Ka = 1.8 x 10-5
(A)
(D)
H3AsO4/NaH2AsO4
CH3COOH/KCH3COO
4.
A solution of 25.0 mL of 0.25 M iodous acid, HIO2 (Ka = 2.9 x 10-5 ) is titrated with a solution of 0.125 M sodium hydroxide.
What is the pH when 25.0 mL of NaOH have been added?
(A)
2.57
(B)
(B)
(E)
4.54
HCOOH/NaHCOO
NH4Cl/NH3
(C)
2.9 x 10-5
1
(C)
(D)
C5H5N/ C5H5NHCl
8.97
(E)
9.46
5.
Which indicator would be the best to use when titrating potassium hydroxide with nitric acid?
(A)
(C)
(E)
phenolphthalein (pH range 8-10)
methyl red (pH range 4.2-6.2)
alizarin yellow R (pH range 10-12)
6.
100 mL of a buffer that consists of 0.20 M NH3 and 0.20 M NH4Cl is titrated with 25 mL of 0.20 M HCl. Calculate the pH of the
resulting solution given that the Kb for NH3 is 1.8 x 10-5.
(A)
4.74
7.
Determine the Ksp value of iron (II) hydroxide, given that its solubility in water at 25 ºC is 1.01 x 10-5 mol/liter.
(A)
(D)
1.02 x 10-10
4.12 x 10-15
8.
Given that the Ksp for silver iodide is 8.3 x 10-17, what is the solubility in mol/liter of silver iodide in a solution that is 0.25 M
MgI2?
(A)
(D)
9.1 x 10-9
4.2 x 10-17
9.
Given that the Ksp for calcium fluoride [CaF2] is 3.2 x 10-15, which of the following describes a solution that is 2.00 x 10-5 M NaF
and 2.00 x 10-5 M Ca(NO3)2?
(A)
(B)
(C)
(D)
(E)
Q = 4 x 10-10 and there will be a precipitate formed
Q = 8 x 10-10 and there will be a precipitate formed
Q = 8 x 10-15 and there will be no precipitate formed
Q = 1.3 x 10-13 and there will be a precipitate formed
Q = 8 x 10-15 and there will be a precipitate formed
(B)
(B)
(D)
4.97
(C)
(B)
(E)
(B)
(E)
9.03
1.03 x 10-15
3.18 x 10-3
bromothymol blue (pH range 6-7.5)
thymol blue (pH range 1.2-2.8 and 8 to 9.2)
(D)
(C)
3.3 x 10-16
2.1 x 10-17
(C)
2
9.26
(E)
9.48
2.06 x 10-15
1.7 x 10-16
10.
Which of the following statements is TRUE concerning the solubility of zinc carbonate?
(A)
(B)
(C)
(D)
(E)
Zinc carbonate would be more soluble in a solution of zinc chloride?
Zinc carbonate would be less soluble in a solution that has pH less than 7.
Zinc carbonate would be less soluble in a solution of sodium chloride
Zinc carbonate would be less soluble in a solution of potassium carbonate
It is impossible to change the solubility of zinc carbonate at a particular temperature
11.
The Second Law of Thermodynamics states that
(A)
(B)
(C)
(D)
(E)
energy is conserved in a spontaneous process.
the entropy of the universe increases during a spontaneous process.
the heat content of the universe increases during a spontaneous process.
all of these are valid components of the second law.
none of these is correct.
12.
In which of the following reactions do you expect to have the largest increase in entropy?
(A)
(D)
I2(s) → I2(g)
Hg(l) + S(s) → HgS(s)
13.
For the reaction 2 SO2 (g) + O2(g) → 2 SO3(g), ∆Go is -141.78 kJ mol-1. What is ∆G0f of gaseous sulfur dioxide given that ∆G0f
for SO3(g) is -371.08 kJ mol-1.
(A)
(D)
229.30 kJ mol-1
-600.38 kJ mol-1.
14.
Which of the following would you expect to have the largest entropy?
(A)
He(g)
(B)
(E)
(B)
(E)
(B)
C2H6(g)
2IF(g) → I2(g) + F2(g)
CuSO4(s) + 5H2O(l) → CuSO4.H2O(s)
(C)
Mn(s) + O2(g) → MnO2(s)
–141.78 kJ mol-1
(C)
–300.19 kJ mol-1
This cannot be determined from the available information
(C)
CH4(g)
3
(D)
CaCO3(s)
(E)
HNO3(l)
15.
For the reaction, X + Y → A + B, ∆Go is –1324 kJ. Which one of the following statements is NOT valid concerning the reaction?
(A)
(C)
(E)
The reaction is thermodynamically favorable.
The products are more stable than the reactants.
Three of these statements are valid.
16.
The exothermic reaction, 2 Cu(s) + O2(g) → 2 CuO(s), is spontaneous
(A)
(C)
(E)
At high temperatures
At all temperatures
Cannot be determined with the available information
17.
Given that at 25oC ∆Gof = -16.48 kJ/mol for NH3(g), what is the equilibrium constant at that temperature for the reaction 2NH3(g)
' N2(g) + 3 H2(g)?
(A)
1.01
18.
Estimate ∆Go at 300oC for the reaction below given the listed values of ∆Hof and Sº for each species at 25oC.
(B)
1.7 x 10-6
(B)
(D)
(C)
(B)
(D)
The reaction is spontaneous as written.
The reaction will proceed rapidly from left to right.
At low temperatures
The reaction is nonspontaneous at all temperatures
1.3 x 10-3
(D)
7.7 x 102
(E)
5.9 x 105
(E)
–1.182 kJ
P4O10(s) + 6 H2O(l) → 4 H3PO4(s)
∆Hof (kJ/mol)
So (J/K.mol)
-2984
228.9
-285.8
69.91
(B)
-1281
110.5
(A)
–363.7 kJ
117.87 kJ
(C)
19.
Which of the following statements is incorrect.
(A)
(C)
(E)
In Cr2O72-, Cr has an oxidation number of +6.
In phosphate, the P has an oxidation number of +5.
In perchloric acid, the Cl has an oxidation number of +7.
–62.30 kJ
(B)
(D)
4
(D)
–307.0 kJ
In NH3, the N has an oxidation number of -3.
In hydrogen peroxide, the O has an oxidation number of -2.
20.
Balance the following equation in basic solution using the smallest possible integral coefficients. What is the coefficient of water
in this balanced equation?
Se2-(aq) + SO32-(aq) ⎯→ Se(s) + S2O32-(aq)
(A)
2
(B)
3
(C)
4
5
(D)
6
(E)
8
CHEM 1332
SPRING 2004
THIRD EXAM - APRIL, 23rd – Version 2
1.
The exothermic reaction, 2 Cu(s) + O2(g) → 2 CuO(s), is spontaneous
(A)
(C)
(E)
At high temperatures
At all temperatures
Cannot be determined with the available information
2.
Given that at 25oC ∆Gof = -16.48 kJ/mol for NH3(g), what is the equilibrium constant at that temperature for the reaction 2NH3(g)
' N2(g) + 3 H2(g)?
(A)
1.01
3.
Estimate ∆Go at 300oC for the reaction below given the listed values of ∆Hof and Sº for each species at 25oC.
(B)
1.7 x 10-6
(C)
(B)
(D)
At low temperatures
The reaction is nonspontaneous at all temperatures
1.3 x 10-3
(D)
7.7 x 102
(E)
5.9 x 105
(E)
–1.182 kJ
P4O10(s) + 6 H2O(l) → 4 H3PO4(s)
∆Hof (kJ/mol)
So (J/K.mol)
-2984
228.9
-285.8
69.91
(B)
-1281
110.5
(A)
–363.7 kJ
117.87 kJ
(C)
4.
Which of the following statements is incorrect.
(A)
(C)
(E)
In Cr2O72-, Cr has an oxidation number of +6.
In phosphate, the P has an oxidation number of +5.
In perchloric acid, the Cl has an oxidation number of +7.
–62.30 kJ
(B)
(D)
1
(D)
–307.0 kJ
In NH3, the N has an oxidation number of -3.
In hydrogen peroxide, the O has an oxidation number of -2.
5.
Balance the following equation in basic solution using the smallest possible integral coefficients. What is the coefficient of water
in this balanced equation?
Se2-(aq) + SO32-(aq) ⎯→ Se(s) + S2O32-(aq)
(A)
2
(B)
3
(C)
6.
The Second Law of Thermodynamics states that
(A)
(B)
(C)
(D)
(E)
energy is conserved in a spontaneous process.
the entropy of the universe increases during a spontaneous process.
the heat content of the universe increases during a spontaneous process.
all of these are valid components of the second law.
none of these is correct.
7.
In which of the following reactions do you expect to have the largest increase in entropy?
(A)
(D)
I2(s) → I2(g)
Hg(l) + S(s) → HgS(s)
8.
For the reaction 2 SO2 (g) + O2(g) → 2 SO3(g), ∆Go is -141.78 kJ mol-1. What is ∆G0f of gaseous sulfur dioxide given that ∆G0f
for SO3(g) is -371.08 kJ mol-1.
(A)
(D)
229.30 kJ mol-1
-600.38 kJ mol-1.
9.
Which of the following would you expect to have the largest entropy?
(A)
He(g)
(B)
(E)
(B)
(E)
(B)
C2H6(g)
4
(D)
2IF(g) → I2(g) + F2(g)
CuSO4(s) + 5H2O(l) → CuSO4.H2O(s)
6
(C)
(E)
8
Mn(s) + O2(g) → MnO2(s)
–141.78 kJ mol-1
(C)
–300.19 kJ mol-1
This cannot be determined from the available information
(C)
CH4(g)
2
(D)
CaCO3(s)
(E)
HNO3(l)
10.
For the reaction, X + Y → A + B, ∆Go is –1324 kJ. Which one of the following statements is NOT valid concerning the reaction?
(A)
(C)
(E)
The reaction is thermodynamically favorable.
The products are more stable than the reactants.
Three of these statements are valid.
11.
100 mL of a buffer that consists of 0.20 M NH3 and 0.20 M NH4Cl is titrated with 25 mL of 0.20 M HCl. Calculate the pH of the
resulting solution given that the Kb for NH3 is 1.8 x 10-5.
(A)
4.74
12.
Determine the Ksp value of iron (II) hydroxide, given that its solubility in water at 25 ºC is 1.01 x 10-5 mol/liter.
(A)
(D)
1.02 x 10-10
4.12 x 10-15
13.
Given that the Ksp for silver iodide is 8.3 x 10-17, what is the solubility in mol/liter of silver iodide in a solution that is 0.25 M
MgI2?
(A)
(D)
9.1 x 10-9
4.2 x 10-17
14.
Given that the Ksp for calcium fluoride [CaF2] is 3.2 x 10-15, which of the following describes a solution that is 2.00 x 10-5 M NaF
and 2.00 x 10-5 M Ca(NO3)2?
(A)
(B)
(C)
(D)
(E)
Q = 4 x 10-10 and there will be a precipitate formed
Q = 8 x 10-10 and there will be a precipitate formed
Q = 8 x 10-15 and there will be no precipitate formed
Q = 1.3 x 10-13 and there will be a precipitate formed
Q = 8 x 10-15 and there will be a precipitate formed
(B)
4.97
(B)
(D)
(C)
(B)
(E)
(B)
(E)
9.03
1.03 x 10-15
3.18 x 10-3
The reaction is spontaneous as written.
The reaction will proceed rapidly from left to right.
(D)
(C)
3.3 x 10-16
2.1 x 10-17
(C)
3
9.26
(E)
9.48
2.06 x 10-15
1.7 x 10-16
15.
Which of the following statements is TRUE concerning the solubility of zinc carbonate?
(A)
(B)
(C)
(D)
(E)
Zinc carbonate would be more soluble in a solution of zinc chloride?
Zinc carbonate would be less soluble in a solution that has pH less than 7.
Zinc carbonate would be less soluble in a solution of sodium chloride
Zinc carbonate would be less soluble in a solution of potassium carbonate
It is impossible to change the solubility of zinc carbonate at a particular temperature
16.
Which of the following mixtures would NOT be described as a buffer solution?
(A)
(C)
(E)
0.15 M NH4Cl and 0.25 M NH3
0.25 M HNO2 and 0.15 M KNO2
0.30 M NH3 and 0.15 M HCl
17.
Given that the Kb of NH3 is 1.8 x 10-5, calculate the pH of a solution that is made by mixing 40.0 mL of 0.25 M NH3 and 10.0 mL
of 0.45 M NH4Br.
(A)
4.4
18.
A buffer is required that has a pH of 4. Which of the following acid/base pairs would be the most suitable? You may need the
dissociation constants:
HCOOH
CH3COOH
H3AsO4
C5H5N
NH3
(A)
(D)
(B)
(B)
(D)
5.0
(C)
8.7
0.20 M NaOH and 0.40 M CH3COOH
0.25 M HNO3 and 0.15 M KNO3
(D)
9.0
Ka = 1.8 x 10-4
Ka = 1.8 x 10-5
Ka1 = 6.0 x 10-3, Ka2 = 1.1 x 10-7, Ka3 = 3 x 10-12
Ka = 1.7 x 10-9
Ka = 1.8 x 10-5
H3AsO4/NaH2AsO4
CH3COOH/KCH3COO
(B)
(E)
HCOOH/NaHCOO
NH4Cl/NH3
4
(C)
C5H5N/ C5H5NHCl
(E)
9.6
19.
A solution of 25.0 mL of 0.25 M iodous acid, HIO2 (Ka = 2.9 x 10-5 ) is titrated with a solution of 0.125 M sodium hydroxide.
What is the pH when 25.0 mL of NaOH have been added?
(A)
2.57
20.
Which indicator would be the best to use when titrating potassium hydroxide with nitric acid?
(A)
(C)
(E)
phenolphthalein (pH range 8-10)
methyl red (pH range 4.2-6.2)
alizarin yellow R (pH range 10-12)
(B)
4.54
(C)
2.9 x 10-5
(B)
(D)
5
(D)
8.97
bromothymol blue (pH range 6-7.5)
thymol blue (pH range 1.2-2.8 and 8 to 9.2)
(E)
9.46
CHEM 1332
SPRING 2004
THIRD EXAM - APRIL, 23rd – Version 3
1.
100 mL of a buffer that consists of 0.20 M NH3 and 0.20 M NH4Cl is titrated with 25 mL of 0.20 M HCl. Calculate the pH of the
resulting solution given that the Kb for NH3 is 1.8 x 10-5.
(A)
4.74
2.
Determine the Ksp value of iron (II) hydroxide, given that its solubility in water at 25 ºC is 1.01 x 10-5 mol/liter.
(A)
(D)
1.02 x 10-10
4.12 x 10-15
3.
Given that the Ksp for silver iodide is 8.3 x 10-17, what is the solubility in mol/liter of silver iodide in a solution that is 0.25 M
MgI2?
(A)
(D)
9.1 x 10-9
4.2 x 10-17
4.
Given that the Ksp for calcium fluoride [CaF2] is 3.2 x 10-15, which of the following describes a solution that is 2.00 x 10-5 M NaF
and 2.00 x 10-5 M Ca(NO3)2?
(A)
(B)
(C)
(D)
(E)
Q = 4 x 10-10 and there will be a precipitate formed
Q = 8 x 10-10 and there will be a precipitate formed
Q = 8 x 10-15 and there will be no precipitate formed
Q = 1.3 x 10-13 and there will be a precipitate formed
Q = 8 x 10-15 and there will be a precipitate formed
(B)
4.97
(C)
(B)
(E)
(B)
(E)
9.03
1.03 x 10-15
3.18 x 10-3
(D)
(C)
3.3 x 10-16
2.1 x 10-17
(C)
1
9.26
(E)
9.48
2.06 x 10-15
1.7 x 10-16
5.
Which of the following statements is TRUE concerning the solubility of zinc carbonate?
(A)
(B)
(C)
(D)
(E)
Zinc carbonate would be more soluble in a solution of zinc chloride?
Zinc carbonate would be less soluble in a solution that has pH less than 7.
Zinc carbonate would be less soluble in a solution of sodium chloride
Zinc carbonate would be less soluble in a solution of potassium carbonate
It is impossible to change the solubility of zinc carbonate at a particular temperature
6.
Which of the following mixtures would NOT be described as a buffer solution?
(A)
(C)
(E)
0.15 M NH4Cl and 0.25 M NH3
0.25 M HNO2 and 0.15 M KNO2
0.30 M NH3 and 0.15 M HCl
7.
Given that the Kb of NH3 is 1.8 x 10-5, calculate the pH of a solution that is made by mixing 40.0 mL of 0.25 M NH3 and 10.0 mL
of 0.45 M NH4Br.
(A)
4.4
8.
A buffer is required that has a pH of 4. Which of the following acid/base pairs would be the most suitable? You may need the
dissociation constants:
HCOOH
CH3COOH
H3AsO4
C5H5N
NH3
(A)
(D)
(B)
(B)
(D)
5.0
(C)
8.7
0.20 M NaOH and 0.40 M CH3COOH
0.25 M HNO3 and 0.15 M KNO3
(D)
9.0
Ka = 1.8 x 10-4
Ka = 1.8 x 10-5
Ka1 = 6.0 x 10-3, Ka2 = 1.1 x 10-7, Ka3 = 3 x 10-12
Ka = 1.7 x 10-9
Ka = 1.8 x 10-5
H3AsO4/NaH2AsO4
CH3COOH/KCH3COO
(B)
(E)
HCOOH/NaHCOO
NH4Cl/NH3
2
(C)
C5H5N/ C5H5NHCl
(E)
9.6
9.
A solution of 25.0 mL of 0.25 M iodous acid, HIO2 (Ka = 2.9 x 10-5 ) is titrated with a solution of 0.125 M sodium hydroxide.
What is the pH when 25.0 mL of NaOH have been added?
(A)
2.57
10.
Which indicator would be the best to use when titrating potassium hydroxide with nitric acid?
(A)
(C)
(E)
phenolphthalein (pH range 8-10)
methyl red (pH range 4.2-6.2)
alizarin yellow R (pH range 10-12)
11.
The exothermic reaction, 2 Cu(s) + O2(g) → 2 CuO(s), is spontaneous
(A)
(C)
(E)
At high temperatures
At all temperatures
Cannot be determined with the available information
12.
Given that at 25oC ∆Gof = -16.48 kJ/mol for NH3(g), what is the equilibrium constant at that temperature for the reaction 2NH3(g)
' N2(g) + 3 H2(g)?
(A)
1.01
13.
Estimate ∆Go at 300oC for the reaction below given the listed values of ∆Hof and Sº for each species at 25oC.
(B)
(B)
4.54
(C)
2.9 x 10-5
(B)
(D)
1.7 x 10-6
(C)
(B)
(D)
(D)
8.97
(E)
9.46
bromothymol blue (pH range 6-7.5)
thymol blue (pH range 1.2-2.8 and 8 to 9.2)
At low temperatures
The reaction is nonspontaneous at all temperatures
1.3 x 10-3
(D)
7.7 x 102
(E)
5.9 x 105
(E)
–1.182 kJ
P4O10(s) + 6 H2O(l) → 4 H3PO4(s)
∆Hof (kJ/mol)
So (J/K.mol)
(A)
–363.7 kJ
-2984
228.9
-285.8
69.91
(B)
117.87 kJ
-1281
110.5
(C)
–62.30 kJ
3
(D)
–307.0 kJ
14.
Which of the following statements is incorrect.
(A)
(C)
(E)
In Cr2O72-, Cr has an oxidation number of +6.
In phosphate, the P has an oxidation number of +5.
In perchloric acid, the Cl has an oxidation number of +7.
15.
Balance the following equation in basic solution using the smallest possible integral coefficients. What is the coefficient of water
in this balanced equation?
(B)
(D)
In NH3, the N has an oxidation number of -3.
In hydrogen peroxide, the O has an oxidation number of -2.
Se2-(aq) + SO32-(aq) ⎯→ Se(s) + S2O32-(aq)
(A)
2
(B)
3
(C)
16.
The Second Law of Thermodynamics states that
(A)
(B)
(C)
(D)
(E)
energy is conserved in a spontaneous process.
the entropy of the universe increases during a spontaneous process.
the heat content of the universe increases during a spontaneous process.
all of these are valid components of the second law.
none of these is correct.
17.
In which of the following reactions do you expect to have the largest increase in entropy?
(A)
(D)
I2(s) → I2(g)
Hg(l) + S(s) → HgS(s)
18.
For the reaction 2 SO2 (g) + O2(g) → 2 SO3(g), ∆Go is -141.78 kJ mol-1. What is ∆G0f of gaseous sulfur dioxide given that ∆G0f
for SO3(g) is -371.08 kJ mol-1.
(A)
(D)
229.30 kJ mol-1
-600.38 kJ mol-1.
(B)
(E)
(B)
(E)
4
(D)
2IF(g) → I2(g) + F2(g)
CuSO4(s) + 5H2O(l) → CuSO4.H2O(s)
6
(C)
(E)
Mn(s) + O2(g) → MnO2(s)
–141.78 kJ mol-1
(C)
–300.19 kJ mol-1
This cannot be determined from the available information
4
8
19.
Which of the following would you expect to have the largest entropy?
(A)
He(g)
20.
For the reaction, X + Y → A + B, ∆Go is –1324 kJ. Which one of the following statements is NOT valid concerning the reaction?
(A)
(C)
(E)
The reaction is thermodynamically favorable.
The products are more stable than the reactants.
Three of these statements are valid.
(B)
C2H6(g)
(C)
CH4(g)
(B)
(D)
5
(D)
CaCO3(s)
(E)
The reaction is spontaneous as written.
The reaction will proceed rapidly from left to right.
HNO3(l)
CHEM 1332
SPRING 2004
THIRD EXAM - APRIL, 23rd – Version 4
1.
The Second Law of Thermodynamics states that
(A)
(B)
(C)
(D)
(E)
energy is conserved in a spontaneous process.
the entropy of the universe increases during a spontaneous process.
the heat content of the universe increases during a spontaneous process.
all of these are valid components of the second law.
none of these is correct.
2.
In which of the following reactions do you expect to have the largest increase in entropy?
(A)
(D)
I2(s) → I2(g)
Hg(l) + S(s) → HgS(s)
3.
For the reaction 2 SO2 (g) + O2(g) → 2 SO3(g), ∆Go is -141.78 kJ mol-1. What is ∆G0f of gaseous sulfur dioxide given that ∆G0f
for SO3(g) is -371.08 kJ mol-1.
(A)
(D)
229.30 kJ mol-1
-600.38 kJ mol-1.
4.
Which of the following would you expect to have the largest entropy?
(A)
He(g)
5.
For the reaction, X + Y → A + B, ∆Go is –1324 kJ. Which one of the following statements is NOT valid concerning the reaction?
(A)
(C)
(E)
The reaction is thermodynamically favorable.
The products are more stable than the reactants.
Three of these statements are valid.
(B)
(E)
(B)
(E)
(B)
2IF(g) → I2(g) + F2(g)
CuSO4(s) + 5H2O(l) → CuSO4.H2O(s)
(C)
Mn(s) + O2(g) → MnO2(s)
–141.78 kJ mol-1
(C)
–300.19 kJ mol-1
This cannot be determined from the available information
C2H6(g)
(C)
CH4(g)
(B)
(D)
1
(D)
CaCO3(s)
(E)
The reaction is spontaneous as written.
The reaction will proceed rapidly from left to right.
HNO3(l)
6.
The exothermic reaction, 2 Cu(s) + O2(g) → 2 CuO(s), is spontaneous
(A)
(C)
(E)
At high temperatures
At all temperatures
Cannot be determined with the available information
7.
Given that at 25oC ∆Gof = -16.48 kJ/mol for NH3(g), what is the equilibrium constant at that temperature for the reaction 2NH3(g)
' N2(g) + 3 H2(g)?
(A)
1.01
8.
Estimate ∆Go at 300oC for the reaction below given the listed values of ∆Hof and Sº for each species at 25oC.
(B)
1.7 x 10-6
(C)
(B)
(D)
At low temperatures
The reaction is nonspontaneous at all temperatures
1.3 x 10-3
(D)
7.7 x 102
(E)
5.9 x 105
(E)
–1.182 kJ
P4O10(s) + 6 H2O(l) → 4 H3PO4(s)
∆Hof (kJ/mol)
So (J/K.mol)
-2984
228.9
-285.8
69.91
(B)
-1281
110.5
(A)
–363.7 kJ
117.87 kJ
(C)
–62.30 kJ
9.
Which of the following statements is incorrect.
(A)
(C)
(E)
In Cr2O72-, Cr has an oxidation number of +6.
In phosphate, the P has an oxidation number of +5.
In perchloric acid, the Cl has an oxidation number of +7.
10.
Balance the following equation in basic solution using the smallest possible integral coefficients. What is the coefficient of water
in this balanced equation?
(B)
(D)
(D)
–307.0 kJ
In NH3, the N has an oxidation number of -3.
In hydrogen peroxide, the O has an oxidation number of -2.
Se2-(aq) + SO32-(aq) ⎯→ Se(s) + S2O32-(aq)
(A)
2
(B)
3
(C)
4
2
(D)
6
(E)
8
11.
Which of the following mixtures would NOT be described as a buffer solution?
(A)
(C)
(E)
0.15 M NH4Cl and 0.25 M NH3
0.25 M HNO2 and 0.15 M KNO2
0.30 M NH3 and 0.15 M HCl
12.
Given that the Kb of NH3 is 1.8 x 10-5, calculate the pH of a solution that is made by mixing 40.0 mL of 0.25 M NH3 and 10.0 mL
of 0.45 M NH4Br.
(A)
4.4
13.
A buffer is required that has a pH of 4. Which of the following acid/base pairs would be the most suitable? You may need the
dissociation constants:
HCOOH
CH3COOH
H3AsO4
C5H5N
NH3
(B)
(B)
(D)
5.0
(C)
0.20 M NaOH and 0.40 M CH3COOH
0.25 M HNO3 and 0.15 M KNO3
8.7
(D)
9.0
(E)
9.6
Ka = 1.8 x 10-4
Ka = 1.8 x 10-5
Ka1 = 6.0 x 10-3, Ka2 = 1.1 x 10-7, Ka3 = 3 x 10-12
Ka = 1.7 x 10-9
Ka = 1.8 x 10-5
(A)
(D)
H3AsO4/NaH2AsO4
CH3COOH/KCH3COO
14.
A solution of 25.0 mL of 0.25 M iodous acid, HIO2 (Ka = 2.9 x 10-5 ) is titrated with a solution of 0.125 M sodium hydroxide.
What is the pH when 25.0 mL of NaOH have been added?
(A)
2.57
15.
Which indicator would be the best to use when titrating potassium hydroxide with nitric acid?
(A)
(C)
(E)
phenolphthalein (pH range 8-10)
methyl red (pH range 4.2-6.2)
alizarin yellow R (pH range 10-12)
(B)
(B)
(E)
4.54
HCOOH/NaHCOO
NH4Cl/NH3
(C)
(C)
2.9 x 10-5
(B)
(D)
3
(D)
C5H5N/ C5H5NHCl
8.97
bromothymol blue (pH range 6-7.5)
thymol blue (pH range 1.2-2.8 and 8 to 9.2)
(E)
9.46
16.
100 mL of a buffer that consists of 0.20 M NH3 and 0.20 M NH4Cl is titrated with 25 mL of 0.20 M HCl. Calculate the pH of the
resulting solution given that the Kb for NH3 is 1.8 x 10-5.
(A)
4.74
17.
Determine the Ksp value of iron (II) hydroxide, given that its solubility in water at 25 ºC is 1.01 x 10-5 mol/liter.
(A)
(D)
1.02 x 10-10
4.12 x 10-15
18.
Given that the Ksp for silver iodide is 8.3 x 10-17, what is the solubility in mol/liter of silver iodide in a solution that is 0.25 M
MgI2?
(A)
(D)
9.1 x 10-9
4.2 x 10-17
19.
Given that the Ksp for calcium fluoride [CaF2] is 3.2 x 10-15, which of the following describes a solution that is 2.00 x 10-5 M NaF
and 2.00 x 10-5 M Ca(NO3)2?
(A)
(B)
(C)
(D)
(E)
Q = 4 x 10-10 and there will be a precipitate formed
Q = 8 x 10-10 and there will be a precipitate formed
Q = 8 x 10-15 and there will be no precipitate formed
Q = 1.3 x 10-13 and there will be a precipitate formed
Q = 8 x 10-15 and there will be a precipitate formed
20.
Which of the following statements is TRUE concerning the solubility of zinc carbonate?
(A)
(B)
(C)
(D)
(E)
Zinc carbonate would be more soluble in a solution of zinc chloride?
Zinc carbonate would be less soluble in a solution that has pH less than 7.
Zinc carbonate would be less soluble in a solution of sodium chloride
Zinc carbonate would be less soluble in a solution of potassium carbonate
It is impossible to change the solubility of zinc carbonate at a particular temperature
(B)
4.97
(C)
(B)
(E)
(B)
(E)
9.03
1.03 x 10-15
3.18 x 10-3
(D)
(C)
3.3 x 10-16
2.1 x 10-17
(C)
4
9.26
(E)
9.48
2.06 x 10-15
1.7 x 10-16