Determination of the molar mass

Question

Assignment:

Determiniation of the Molar Mass and Ionization Constant of a Weak Monoprotic Acid

Acetic Acid + Water yields Conjugate Base + Hydronium Ion  Or HA + H20 ↔ H₃O⁺ + A^-

Calculation of the ionization constant for acetic acid from the measured pH of acetic acid samples

Acetic Acid titrated with Sodium Hydroxide and the following was determined or known before experiment:

Avg. molar concentration of acetic acid titrated = 0.0455 mol/L

Avg. pH = 3.19

Standardized NaOH = 0.097 mol/L

Mass concentration of acetic acid = 2.4 g/L

Concentration and Ka calculations:

1. Calculation of [H₃0⁺] = 10^-3.19 = 6.46 X 10-⁴ ?? - (Is this the way to find the hydronium concentration?)
2. Calculation of  [A^-] =
3. Calculation of [HA] =
4. Calculation of Ka = [H₃0⁺] [A^-]        =

          [HA]

Measurement of the pKa of Acetic Acid by the Half-Neutralization Method

Using half the amount of NaOH required for equilibrium from part 1, the average pH vale was determined to be 4.63

1. Calculation of pKa =
2. Calculation of Ka =
3. Calculation of [H₃0⁺] =
4. Calculation of  [A^-] =
5. Calculation of [HA] =

Molar Mass and Ionization Constant of an Unknown Weak Monoprotic Acid

Unknown acid = 1.84 g/L

NaOH Titrant = 0.097 mol/L

Average pH = 2.60

Avg. molar mass = 0.04252 mol/L

1. Calculation of pKa =
2. Calculation of Ka =
3. Calculation of [H₃0⁺] =
4. Calculation of  [A^-] =
5. Calculation of [HA] =

Problem:  OH^- concentration of 0.050 M ammonia is 9.5 X 10^-4

(a) Write the chemical equation for the dissociation of NH₃ in H₂O

            NH₃ + H₂O  ↔  NH₄ + OH^-

(b)  Equilibrium constant expression for reaction of ammonia with water

Kb = [OH^-] [NH⁴⁺]       

[NH₃]

(c) Calculate Kb using the above information.

Provide complete and step by step solution for the question and show calculations and use formulas.