Question

what is the mass of water molecules in gram

Answer 1

55.5g is the mass of water

Answer 2

18.02 grams

The average mass of one H2O molecule is 18.02 amu. The number of atoms is an exact number, the number of mole is an exact number; they do not affect the number of significant figures. The average mass of one mole of H2O is 18.02 grams. This is stated: the molar mass of water is 18.02 g/mol.

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