CHEM 1412 Practice Exam 3, Chapters 16, 17
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pH = pKa + log ([conj. base]/[weak acid])
G=
H–T
S
G = G° + RT ln Q G° = –RT ln Keq R = 8.314 J/mole K
Circle your choice on multiple choice questions. Show you work for calculation problems.
A periodic table is attached to the end of the exam. Good luck!
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1. In neutral solution
a) [H+] = [OH–] b) [H+] > [OH–] c) [H+] < [OH–] d) [H+] = 1 M
2. What is the pH of a 0.25 M solution of HCl?
a) 0.82 b) 0.60 c) 1.20 d) 2.40
3. What is the concentration of OH– ion in a solution of 0.091 M HCl?
a) 2.2 X 10–11 M b) 5.8 X 10–9 M c) 1.1 X 10–13 M d) 1.9 X 10–12 M
4. What is the H+ ion concentration of a 0.15 M solution of NaOH?
a) 6.7 X 10–14 M b) 5.0 X 10–15 M c) 4.6 X 10–12 M d) 5.2 X 10–11 M
5. Calculate the pOH of a 0.0992 M NaOH solution.
a) 1.00 b) 2.00 c) 12.00 d) 13.00
6. What is the H+ ion concentration in a solution with pH 13.24?
a) 5.11 X 10–13 M b) 2.29 X 10–15 M c) 5.75 X 10–14 M d) 1.36 X 10–14 M
7. What is the pH of a 0.015 M solution of Ca(OH)2 ?
a) 10.95 b) 11.74 c) 12.37 d) 12.48
8. A Bronsted-Lowry acid is defined as a substance that
a) acts as a proton donor b) decreases [H+] when dissolved in water
c) increases [OH–] when dissolved in water d) acts as a proton acceptor
9. An Arrhenius base is defined as a substance that
a) acts as an electron pair donor b) increases [H+] when dissolved in water
c) increases [OH–] when dissolved in water d) acts as a proton donor
10. A Lewis acid is defined as a substance that
a) acts as an electron pair donor b) acts as an electron pair acceptor
c) increases [H+] when dissolved in water d) acts as a proton donor
11. What is the conjugate acid of the carbonate ion, CO32– ?
a) H2CO3 b) HCO3– c) HCO2– d) HCO4–
12. What is the conjugate acid of the hydrogenphosphate ion, HPO42– ?
a) H3PO4 b) PO43– c) H2PO4– d) H2PO32–
13. Which of the following is a strong acid?
a) HClO2 c) HNO2 c) HClO4 d) H2SO3
14. Which of the following is a weak acid?
a) HCl b) HBr c) HNO2 d) HNO3
15. Which of the following is a strong base?
a) KOH b) KF c) KC2H3O2 d) HNO3
16. Which of the following is a weak base?
a) NaNO3 b) HNO3 c) NH4Cl d) NH3
17. Which is a conjugate pair?
a) LiF and NaF b) HF and HCl c) HF and KF d) HNO2 and HNO3
18. Which is the strongest acid?
a) HClO b) HClO2 c) HClO3 d) HClO4
19. Which one of the following solutions would be neutral (have a pH of 7)?
a) KBr (aq) b) KF (aq) c) NaNO2 (aq) d) NH4Cl (aq)
20. Based on its Ka value, which of the following is the strongest acid?
a) HF, Ka = 6.8 X 10–4 b) HClO, Ka = 3.0 X 10–8
c) HNO2, Ka = 4.5 X 10–4 d) HCN, Ka = 4.9 X 10–10
21. Which of the following pairs could be used to make a buffer solution?
a) KC2H3O2 and NaC2H3O2 b) NH4Br and NH4Cl
c) HC2H3O2 and NaC2H3O2 d) NaOH and HCl
22. Write the equation for the dissociation of the weak acid HCN in aqueous solution.
Write the Ka expression for this reaction.
23. Write the net ionic equation (without spectator ion) for the hydrolysis reaction of the weak base
NaCN with water. Write the Kb expression for this reaction.
24. Write the equation for the solution of the slightly soluble solid Fe(OH)3 in water.
Write the Ksp expression for this process.
25. Calculate the pH of a solution of 0.15 M hypobromous acid, HBrO. Ka for HBrO is 2.1 X 10–9.
a) 8.50 b) 6.33 c) 5.25 d) 4.75
26. Calculate the pH of a 0.30 M solution of sodium hypobromite, NaBrO. The Ka of hypobromous acid,
HBrO, is 2.1 X 10–9.
a) 4.50 b) 6.27 c) 9.45 d) 11.08
27. What is the molarity of an HCl solution if 25.0 mL of this solution required 17.80 mL of 0.108 M
NaOH to reach the end point in a titration?
a) 0.228 M b) 0.139 M c) 0.0642 M d) 0.0769 M
28. What is the pH of a solution that is 0.10 M in HClO and 0.25 M in NaClO?
Ka for HClO is 3.0 X 10–8.
a) 5.22 b) 7.38 c) 8.55 d) 7.92
29. Calculate the molar solubility of ferric hydroxide, Fe(OH)3. Ksp for Fe(OH)3 = 1.6 X 10–39.
a) 8.8 X 10–11 M b) 6.7 X 10–9 M c) 4.3 X 10–6 M d) 9.1 X 10–5 M