Question

calculate the mass of 1 molecule of ammonia and oxygen

Answer 1

See molar mass of a compound or molecular mass of an element is the mass of 1 mole of that substance. 1 molecule of oxygen = (32 / 6.023 x 1023) = 5.31 x 10-23 g = 5.31 x 10-20 kg. Similarly, 1 mole of ammonia weighs 17 g.