The pH of weak acids

When a strong monobasic acid, HA, completely dissociates what is [H+] equal to?

[H+] = [HA]

When HA molecules dissociate H+ and A- ions are what?

H+ and A- ions are formed in equal quantities

What is the first approximation for the Ka?

The dissociation of water is negligible

[H+]_eqm = [A-]_eqm

What is the second assumption for the Ka of water?

the concentration of acid is much greater than the H+ concentration at equilibrium

[HA]_eqm = [HA]_start

Because of the approximations, the Ka can be simplified to what? When is this applicable?

ONLY for aqueous solution of a weak acid

How can you determine the Ka for a weak acid experimentally?

by preparing a standard solution of the weak acid of a known concentration

By measuring the pH of the standard solution using a pH meter

How do you calculate percentage dissociation?

[H⁺] / [concentration of acid]