Calculate the molar mass of: a) copper oxide (2); b) sodium oxide; c) phosphoric acid H3 PO4.

The molar mass of a substance consists of the atomic mass of the elements that make up the molecule.

Mr (O) = 16 g / mol

Mr (Cu) = 63 g / mol

Mr (Na) = 23 g / mol

Mr (H) = 1 g / mol

Mr (P) = 31 g / mol

a) copper oxide

Mr (CuO) = 63 + 16 = 79 g / mol;

b) sodium oxide

Mr (Na2O) = 23 * 2 + 16 = 72 g / mol;

c) phosphoric acid

Mr (H3PO4) = 1 * 3 + 31 + 16 * 4 = 98 g / mol.