Question

a solution made by dissolving 2.733g KH2PO4 and 4.508g K2HPO4 in water to give 250 ml of solution.

is the answer...

7.432= ph

Answer 1

What's the question?

Answer 2

What is the pH of the buffer solution

Answer 3

The base is K2HPO4. The acid is KH2PO4.
Convert g base to mols. mols = grams/molar mass. Do the same for the acid. Convert each to M. M = mols/L.
Then substitute into the HH equation and solve for pH.

Answer 4

thank you very much, do i used the molar mass of KH2PO4 altogether or just of H2PO4?

Answer 5

You use the molar mass of the material for which you have a mass; i.e., if your material weighed is KH2PO4 then mols KH2PO4 = grams KH2PO4/molar mass kH2PO4.