ATC

 1. What is the hydronium ion concentration in 0.8450 M HClO? K_a = 2.88 x 10^-8.

 2. The ionization constant of acetic acid, CH₃COOH, is 1.75 x 10^-5.  Find the percent of ionization of 0.200 M acetic acid.

 3. A solution of 1.00 M HA in water ionizes 2.00%.  Find K_a.

 4. What is the hydronium ion concentration of a 0.00300M solution of pyruvic acid, HC₃H₃O₃?  The Ka is 1.40 x 10^-4

 5. Determine the ionization constant of a 0.0070 M aqueous ammonia solution with [OH-] = 3.46 x 10^-4 M.

 6. A sheet of gold weighing 10.0 g and at a temperature of 18.0 °C is placed flat on a sheet of iron weighing 20.0 g and at a temperature of 55.6 °C.  What is the final temperature of the combined metals?  Assume that no heat is lost to the surroundings. (Hint:  The heat gained by gold must be equal to the heat lost by iron.) Specific heat of gold is 0.128 J/g°C, and iron is 0.448 J/g°C.

7. Find the enthalpy change for the reaction below, given the following reactions and subsequent ΔH values:  PCl_5(g) → PCl_3(g) + Cl_2(g)

P_4(s) + 6Cl_2(g) → 4PCl_3(g)           ΔH = -2439 kJ

4PCl_5(g) → P_4(s) + 10Cl_2(g)         ΔH = 3438 kJ