Find Initial Moles

Question

You are given 60.0 mL of a 0.500 M dihydrogen phosphate / hydrogen phosphate buffer. If the buffer is 0.196 M H₂PO₄^- and 0.304 M HPO₄^2-, answer the following:

Give your answers to 3 sigfigs.

Initial moles of H₂PO₄^- : _______ moles

Initial moles of HPO₄^2-: ________ moles

Answer 1

Dihydrogen phosphate = H₂PO₄^-

Hydrogen phosphate = HPO₄^2-

60.0 mls x 1 L / 1000 mls x 0.196 mol / L H₂PO₄^- = 0.0118 moles H₂PO₄^-

60.0 mls x 1 L / 1000 mls x 0.304 mol / L HPO₄^2- = 0.0182 moles HPO₄^2-