How many molecules of water and oxygen atoms are present in 0.9g of water?

Explanation

Gram-molecular mass of water =18g
Number of moles in 0.9g of water `=(0.9)/(18)=0.05`
Number of water molecular in one mole of water =18g
Number of moles in 0.9g of water `=(0.9)/(18)=0.05`
Number of water molecules in one mole of water
`=6.02xx10^(23)`
Number of molecules of water in 0.05 moles.
`=0.05xx6.02xx10^(23)`
`=3.010xx10^(22)`
As one molecular of water contains one oxygen atom.
So, number of oxygen atoms in `3.010xx10^(22)` molecule of water `=3.010xx10^(22)`