Calculate the number of molecules present in 1 litre of water assuming that density of water is `1 g mL^(-1)`.

Explanation

1 Litre of water = 1000 mi-Mass of 1000 mL of water = Volume x Density
`= 1000 mL xx 1 g mL^(-1) = 1000 g`
No. of moles in 1000 g of `H_(2)O = m/M = 1000/18 = 55.55` moles
No. of molecules (N) = `n xx N_(0)`
`= 55.55 xx 6.022 xx 10^(23) = 3.345 xx 10^(23)` molecules.