So,
pH = 4.20
pKa = -log(1.8 x 10^-5) = 4.74
(acid) = 0.200M
(base) = (0.200M) / (10^(4.20 - 4.74)) = 0.0045M
Grams of sodium acetate = (0.0045M) * (1.00L) * (82.03 g/mol) = 3.69 g
How many grams of sodium acetate( molar mass 82.03 g/mol) must me added to 1.00L of a 0.200M acetic acid solution to form a buffer of 4.20?Ka value for aceic acid is 1.8 x 10^-5.
How do I go about finding the grams from the given information?
http://www.chembuddy.com/?left=pH-calculation&right=pH-buffers-henderson-hasselbalch
You figure concentrations needed from the Henderson Hass equation, then convert concentration to grams, knowing volume and molmass.
I still don't get how to solve my problem because the equation still doesn't make much since to me.
pH = pKa + log(base)/(acid)
You know pH.
Convert Ka to pKa for acetic acid.
You know (acid)
Solve for (base) = sodium acetate.
Convert concentration to grams.
1 answer