Answer to Question #308456 in General Chemistry for Mave

Question

What is the molality of a solution of 2.50 g H3PO4 dissolved in 240 g water?

Answer 1

b(molality) = n(solute)/m(solvent);

M(H₃PO₄) = 98 g/mol;

n(H₃PO₄) = m/M = 2.5/98 = 0.0255 moles;

b(H₃PO₄) = n(H₃PO₄)/m(H₂O) = 0.0255/0.24 = 0.11 mol/kg.

Answer: 0.11 mol/kg.