Chemistry Questionnaire

Spring 2019 – CHM 1102Initials: _____________
Exam 2.1
1. The Kw of water at 10.0C is 2.9×10−15. What is the pH of water at 10.0C?
A. 16.73
B. 7.00
C. 7.27
D. 14.53
E. 6.73
2. Calculate the pH of a 1.5 M solution of methylammonium bromide (CH3NH3Br) at 25C.
The Kb of methylamine (CH3NH2) is 4.37×10−4.
A. 1.59
B. 5.23
C. 5.32
D. 8.77
E. 7.68
3. Of the following solutions, which one(s) would have a basic pH?
i. NaClO
iii. NaClO4
ii. LiBr
iv. Na2SO3
A. i and ii only
B. i and iv only
C. ii, iii, and iv only
D. i only
E. none of the above
4. A 0.10 M HF solution is 8.4% ionized. Calculate the H+ ion concentration in this solution.
A. 0.84 M
B. 0.12 M
C. 0.084 M
D. 0.10×10-3 M
E. 8.4×10-3 M
5. Calculate the pH of a 0.010 M HClO4 solution.
A. 0.00
B. 2.00
C. 7.00
D. 12.00
E. 14.00
6. An amphoteric species:
A. loses a proton in water, according to Arrhenius
B. is an H+ donor, according to Brønsted and Lowry
C. can act as an acid
D. can act as a base
E. can act as an acid or a base
Spring 2019 – CHM 1102
Initials: _____________
Exam 2.1
7. Hypophosphoric acid is a tetraprotic acid (it can lose four protons) whose formula is
H4P2O6. Which of the following is the conjugate base of H2P2O62−?
A. H4P2O6
B. H3P2O6−
C. H2P2O62−
D. HP2O63−
E. P2O64−
8. Calculate the pOH of a 0.001 M Ca(OH)2 solution.
A. 11.0
B. 2.7
C. 11.3
D. 3.0
E. 6.9
9. You take a 10.0 mL solution of a strong acid at pH = 2.00 and add it to 10.0 mL of a second
strong acid solution at pH = 6.00 and mix them. Calculate the pH of the resulting solution.
A. 4.00
B. 2.00
C. 6.00
D. 2.30
E. 3.30
10. Hydrosulfuric acid is a diprotic acid. Calculate the pH of a 0.10 M solution of H2S given
the following:
H2S(aq) ⇌ H+(aq) + HS− (aq)
Ka1 = 5.7×10−8
HS¯(aq) ⇌ H+(aq) + S2− (aq)
Ka2 = 1.0×10−19
A. 8.24
B. 4.12
C. 3.62
D. 7.24
E. 2.88
11. Calculate the Mn2+ concentration in a saturated solution of MnCO3. Ksp for MnCO3 is
3.0×10−16.
A. 3.0×10−16 M
B. 8.7×10−9 M
C. 1.5×10−16 M
D. 3.5×10−8 M
E. 1.7×10−8 M
Spring 2019 – CHM 1102
Initials: _____________
Exam 2.1
12. The equivalence point of a titration of a weak acid with a strong base has:
A. pH = 7.0
B. pH > 7.0
C. pH < 7.0 D. pH = pKa E. pH = 14 13. Which of the following copper salts is/are more soluble in an acidic solution than in a neutral solution? i. CuBr ii. CuCN iii. CuCO3 iv. CuS A. i. only B. i. and iv. only C. ii. and iii. only D. ii., iii. and iv. only E. ii. and iv. only 14. Which of the following solutions has the greatest buffer capacity with respect to the addition of acids and bases? A. 0.125 M NaClO and 0.500 M HClO B. 0.700 M NaClO and 0.300 M HClO C. 0.500 M NaClO and 0.175 M HClO D. 0.400 M NaClO and 0.395 M HClO E. They all have the same buffer capacity. 15. 30.0 mL of 0.15 M KOH was titrated with 0.25 M HNO3 at 25.0C. Calculate the pH after 10.0 mL of HNO3 was added. A. 2.70 B. 1.30 C. 12.70 D. 11.30 E. 12.82 16. Calculate the pH of a buffer solution which contains 0.25 M benzoic acid (HC6H5CO2) and 0.15 M sodium benzoate (NaC6H5CO2). Ka for C6H5CO2H = 6.5×10−5.
A. 3.97
B. 4.83
C. 4.19
D. 3.40
E. 4.41
Spring 2019 – CHM 1102
Initials: _____________
Exam 2.1
17. The molar solubility of SnI2 is 1.28×10−2 M. Calculate Ksp for SnI2.
A. 8.39×10−6
B. 1.28×10−2
C. 4.19×10−6
D. 1.64×10−4
E. 2.10×10−6
18. 50.0 mL of 0.10 M HNO2 was titrated with 0.10 M LiOH. Calculate the pH of the solution
after 25.0 mL of LiOH was added. Ka of HNO2 = 4.5×10−4.
A. 2.17
B. 3.35
C. 2.41
D. 1.48
E. 7.00
19. Calculate the minimum concentration of Mg2+ that must be added (assuming the volume
remains constant) to 0.10 M NaF solution in order to initiate precipitation of MgF2. Ksp for
MgF2 = 6.9×10−9.
A. 1.4×107 M
B. 6.9×10−8 M
C. 6.9×10−9 M
D. 1.7×10−7 M
E. 6.9×10−7 M
20. You have a 500.0 mL solution of a buffer containing 0.20 M acetic acid (HC2H3O2) and
0.30 M sodium acetate. Calculate the pH of this solution after the addition of 0.020 moles
of NaOH. Assume the total volume does not change with the addition of NaOH. Ka for
HC2H3O2 = 1.8×10−5.
A. 4.41
B. 4.74
C. 4.56
D. 4.92
E. 5.07
BONUS:
Calculate the pH at the equivalence point for the titration of 10.0 mL of 0.20 M HC2H3O2 with
0.20 M NaOH at 25.0C. Ka of HC2H3O2 = 1.8×10−5.
A. 4.74
B. 4.98
C. 8.87
D. 5.13
F. 9.02
Spring 2019 – CHM 1102
KEY
1. C
2. B
3. B
4. E
5. B
6. E
7. D
8. B
9. D
10. B
11. E
12. B
13. D
14. D
15. C
16. A
17. A
18. B
19. E
20. E
21. C
Initials: _____________
Exam 2.1