Posted by **Catherine** on Saturday, June 2, 2007 at 4:31pm.

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.