how many moles is equal to half litre of water
The density of water = 1 Kg/ L.
Therefore, mass of 1 litre of water = density of water x Volume (since, density = M / V)
= 1 Kg / L x 1 L
= 1000 g
Thus the mass of ½ litre of water = 1000 x ½ = 500g
Hence, the number of moles in 500g of water = mass / molar mass
= 500 / 18