What is the pH of a buffer solution that contains 0.40 mol nitrous acid (HNO2) and 0.30 mol potassium nitrite (KNO2) in water sufficient to yield 1.0 L of solution?  Hint: The Ka of HNO2 is 4.0 x 10-4.

What is the pH of a buffer solution that contains 0.40 mol hydrocyanic acid (HCN) and 0.30 mol potassium cyanide (KCN) in water sufficient to yield 1.0 L of solution?  Hint: The Ka of HCN is 4.9 x 10-10.

Methanol has a normal boiling point of 340.85 K. What is the standard molar entropy of vaporization, ΔS°vap (in J/K), of methanol at its boiling point? Hint: ΔH°vap = +71.8 kJ/mol

Solid NH4SH is introduced into an evacuated flask at 24oC. The following reaction takes place

Which of the following best describes the equilibrium constant for any reaction with a negative value of ΔG°?

Consider the voltaic cell diagram:  Cr(s) | Cr3⁺(aq) || Pb2⁺ (aq) | Pb (s) What is the standard cell potential, E°cell, (in V) for this voltaic cell? Hint: Refer to the table of standard reduction potentials provided. Half Reaction E° red (V) Ag+ (aq)  + e–  →  Ag (s)  +0.80 Fe3+ (aq)  +   e–  → Fe2+ (aq)   +0.77 Cu2+ (aq)  + 2 e–  → Cu (s)    +0.34 Sn4+ (aq) + 2 e–  → Sn2+ (aq)   +0.15 2H+ (aq) + 2 e–  →  H2 (g)  0.00 Pb2+ (aq) + 2 e –  → Pb (s)  –0.13 Sn2+ (aq)  +  2 e–  → Sn (s)  –0.14 Ni2+ (aq) + 2 e –  → Ni (s)   –0.28 Cd2+ (aq) + 2 e –  → Cd (s)   –0.40 Fe2+ (aq) + 2 e –  → Fe (s) –0.44 Cr3+ (aq) + 3 e– →  Cr (s)      –0.74 Zn2+ (aq) + 2 e –  → Zn (s)  –0.76 Al3+ (aq) + 3 e– →  Al (s) –1.66

Molten calcium iodide (CaI2) undergoes electrolysis. What will be produced at the cathode?

Given the standard reduction potentials below:  Half Reaction E° red (V) Ag+ (aq)  + e–  →  Ag (s)  +0.80 Fe3+ (aq)  +   e–  → Fe2+ (aq)   +0.77 Cu2+ (aq)  + 2 e–  → Cu (s)    +0.34 Sn4+ (aq) + 2 e–  → Sn2+ (aq)   +0.15 2H+ (aq) + 2 e–  →  H2 (g)  0.00 Pb2+ (aq) + 2 e –  → Pb (s)  –0.13 Sn2+ (aq)  +  2 e–  → Sn (s)  –0.14 Ni2+ (aq) + 2 e –  → Ni (s)   –0.28 Cd2+ (aq) + 2 e –  → Cd (s)   –0.40 Fe2+ (aq) + 2 e –  → Fe (s) –0.44 Cr3+ (aq) + 3 e– →  Cr (s)      –0.74 Zn2+ (aq) + 2 e –  → Zn (s)  –0.76 Al3+ (aq) + 3 e– →  Al (s) –1.66   Which of the following  substances would be most easily oxidized by Sn2+?

What is the pH of a iron(II) hydroxide, Fe(OH)2, saturated solution? Hint: The Ksp for Fe(OH)2 is 1.6 x 10-14. Hint: Assume the metal cation does not affect pH.

Consider the following equilibrium reaction: