Question

How many molecules are there in 1gram of water

Answer 1

i think 1 molecule of hydrogen and 1 atom of oxygen

Answer 2

 The molecular mass of water molecule is 18 g/mol. It implies that 1 mol of water molecules weigh 18 g.

Now you can calculate easily the number of water molecules present in 1 g of water. Calculation follows

18 g of water contain 1 mol of water molecules.

or 18 g of water contain 6.022 x 10^23 water molecules.

or 1 g of water contains (6.022 x 10^23)/ 18 water molecules and the number comes out to be 3.3455 x 10^22.

So the number of water molecules present in 1 g of water is 3.3455 x 10^22