Question

Calculate the percent ionization of propionic acid (C2H5COOH) in solutions of each of the following concentrations:

Part A

0.260 M .

Express your answer using two significant figures.

Part B

8.19×10⁻² M .

Express your answer using two significant figures.

Part C

2.01×10⁻² M .

Express your answer using two significant figures.

Answer 1

Part A:

1) Calculate the [H⁺]: Ka for propionic acid is 1.3*10^-5

1.3 x 10^-5 = [(x) (x)] / 0.260

x = 1.8384 x 10^-3 M

2) Divide the [H⁺] by the concentration, then multiply by 100:

(1.8384 x 10^-3 M / 0.260M) x 100 = 0.70% dissociated

Part B:

1) Calculate the [H⁺]: Ka for propionic acid is 1.3*10^-5

1.3 x 10^-5 = [(x) (x)] / 0.0819

x = 1.0318 x 10^-3 M

2) Divide the [H⁺] by the concentration, then multiply by 100:

(1.0318 x 10^-3 M / 0.0819) x 100 = 1.25% dissociated

Part C:

Part C

2.01×10−2 M

1) Calculate the [H⁺]: Ka for propionic acid is 1.3*10^-5

1.3 x 10^-5 = [(x) (x)] / 0.0201

x = 5.117 x 10^-4 M

2) Divide the [H⁺] by the concentration, then multiply by 100:

( 5.117 x 10^-4 M / 0.0201) x 100 = 2.54% dissociated