2046 Exam 2 Form Code A
WRITE YOUR NAME HERE:________________________________________________________
CHM 2046 (Gower sections) Exam 2 (Form Code A) Fall 2014
Instructions: On your scantron sheet enter and bubble in your name, UF ID number, and Form Code. Check your bubbling carefully – bubbling errors will not be negotiated. Turn in your scantron and retain your exam (with your answers circled).
Potentially useful info : Kw = 1 x 10‒14 at 25°C pH = −log [H3O+] pH = pKa + log ([base] / [acid])
R = 0.0821 atm•lit/mol•K or 8.314 J/mol•K Kp = Kc(RT)∆n(gas)
ΔG = ΔH – TΔS ΔG° = ΔH° – TΔS° ΔG° = −RTlnK ΔG = ΔG° + RTlnQ
ΔG°rxn = ∑mΔG°f(prod) − ∑mΔG°f(react) (likewise for ΔH°rxn and ΔS°rxn) ln(K1/K2) = (ΔH°rxn / R){(1/T2) – (1/T1)}
The double-headed arrow used in this exam, ↔, refers to a dynamic equilibrium system.
Assume all systems are at 25°C and all aqueous solutions are prepared with pure water unless otherwise indicated. Assume that ΔS°rxn and ΔH°rxn do not change appreciably with temperature.
1. If a 0.10 M aqueous solution of CH3COOH exhibits a pH of 2.87, predict the pH of a 0.10 M aqueous solution of NaCH3COO at the same temperature. (1) 5.12 (2) 8.87 (3) 9.33 (4) 10.23 (5) 11.13
2. It is determined that a maximum of 2.055 g of Zn(IO3)2 will dissolve in 500. mL of pure water at 25°C. From this information, estimate the ΔG°rxn for the dissolution of zinc iodate at 25°C. (1) 26.4 kJ/mol (2) 22.9 kJ/mol (3) 34.3 kJ/mol (4) 30.9 kJ/mol (5) 36.0 kJ/mol
3. A saturated solution of Ag2SO4 at 25°C contains 0.032 M Ag+ ions. From this information, estimate the ΔG°rxn for the dissolution of silver sulfate at 25°C. (1) 17 kJ/mol (2) 20 kJ/mol (3) 27 kJ/mol (4) 32 kJ/mol (5) 35 kJ/mol
4. When 20.0 mL of 0.100 M NaOH is added to 20.0 mL of 0.400 M NaH2PO4, the pH of the resulting buffer solution is 6.73. What is the acid component of the resulting buffer solution and what is the
CHM 2046 (Gower sections) Exam 2 (Form Code A) Fall 2014
Instructions: On your scantron sheet enter and bubble in your name, UF ID number, and Form Code. Check your bubbling carefully – bubbling errors will not be negotiated. Turn in your scantron and retain your exam (with your answers circled).
Potentially useful info : Kw = 1 x 10‒14 at 25°C pH = −log [H3O+] pH = pKa + log ([base] / [acid])
R = 0.0821 atm•lit/mol•K or 8.314 J/mol•K Kp = Kc(RT)∆n(gas)
ΔG = ΔH – TΔS ΔG° = ΔH° – TΔS° ΔG° = −RTlnK ΔG = ΔG° + RTlnQ
ΔG°rxn = ∑mΔG°f(prod) − ∑mΔG°f(react) (likewise for ΔH°rxn and ΔS°rxn) ln(K1/K2) = (ΔH°rxn / R){(1/T2) – (1/T1)}
The double-headed arrow used in this exam, ↔, refers to a dynamic equilibrium system.
Assume all systems are at 25°C and all aqueous solutions are prepared with pure water unless otherwise indicated. Assume that ΔS°rxn and ΔH°rxn do not change appreciably with temperature.
1. If a 0.10 M aqueous solution of CH3COOH exhibits a pH of 2.87, predict the pH of a 0.10 M aqueous solution of NaCH3COO at the same temperature. (1) 5.12 (2) 8.87 (3) 9.33 (4) 10.23 (5) 11.13
2. It is determined that a maximum of 2.055 g of Zn(IO3)2 will dissolve in 500. mL of pure water at 25°C. From this information, estimate the ΔG°rxn for the dissolution of zinc iodate at 25°C. (1) 26.4 kJ/mol (2) 22.9 kJ/mol (3) 34.3 kJ/mol (4) 30.9 kJ/mol (5) 36.0 kJ/mol
3. A saturated solution of Ag2SO4 at 25°C contains 0.032 M Ag+ ions. From this information, estimate the ΔG°rxn for the dissolution of silver sulfate at 25°C. (1) 17 kJ/mol (2) 20 kJ/mol (3) 27 kJ/mol (4) 32 kJ/mol (5) 35 kJ/mol
4. When 20.0 mL of 0.100 M NaOH is added to 20.0 mL of 0.400 M NaH2PO4, the pH of the resulting buffer solution is 6.73. What is the acid component of the resulting buffer solution and what is the