Question

If the mass of one mole of hydrogen is 1.01 grams; phosphorus, 30.97 grams; and oxygen, 16.0 grams, what is the molar mass of phosphoric acid (H3PO4)?

Answer 1

M(H)=1.01 g/mol
M(P)=30.97 g/mol
M(O)=16.0 g/mol

M(H₃PO₄)=3M(H)+M(P)+4M(O)
M(H₃PO₄)=3*1.01+30.97+4*16.0=98.0 g/mol