Question

1a. A sample of pure NO2 is heated to 339 ∘C at which temperature it partially dissociates according to the equation
2NO2(g)⇌2NO(g)+O2(g)
At equilibrium the density of the gas mixture is 0.520 g/Lat 0.750 atm.

Calculate Kc for the reaction.

b. Calculate the solubility (in grams per 1.00×102mL of solution) of magnesium hydroxide in a solution buffered at pH = 12. How does this compare to the solubility of Mg(OH)2 in pure water?

c. Make a rough sketch of the titration curve from this data by calculating the pH at the beginning of the titration, at one-half of the equivalence point, at the equivalence point, and at 5.0 mL beyond the equivalence point.d

d. For 260.0 mL of a buffer solution that is 0.215 M in HCHO2 and 0.315 M in KCHO2, calculate the initial pH and the final pH after adding 0.0200 mol of NaOH(Ka=1.8⋅10−4).

e. For 260.0 mL of a buffer solution that is 0.3251 M in CH3CH2NH2 and 0.2951 M in CH3CH2NH3Cl, calculate the initial pH and the final pH after adding 0.0200 mol of NaOH(Kb=5.6⋅10−4).

f. A 0.150 M solution of a weak base has a pH of 11.20. Determine Kb for the base.

g. What amount of HCl gas must be added to 1.00 L of a buffer solution that contains [aceticacid]=2.0M and [acetate]=1.0M in order to produce a solution with pH = 4.07?

Answer 1