Question

find mass of one molecule of water

Answer 1

Molar mass water = 18 g/mol 1 mole = 6.02 x 10^23 molecules 18 / 6.02 x 10^23 = 2.99 x 10^-23 g is the mass of one molecule
 

Answer 2

Molar mass of water=2×1+16=18g/mol.

:)1 mol=6.022×10²³ molecules=18g of water

:)1 molecule weigh 18/6.022×10²³=2.99×10²³g