How many molecules of water are present in 0.9 g of water ?

Answer

`3.01 xx 10^(22)` molecules

Explanation

No. of moles of 0.9 g of water `= (("1 mol"))/(("18.0 g"))=(0.9g)=0.05` mol
No. of `H_(2)O` molecules present `= ((6.022 xx10^(23)"molecules"))/(("1.0 mol"))xx(0.01mol)`
`= 3.01 xx 10^(22)` molecules.