Question

molarity of pure water

Answer 1

1000/18 = 55.55 M .
as density of water is 1000g /l
and molar mass of water is 18 grams

Answer 2

The molarity of water depends on the temperature.

We know, Water density is = 1 gram/mL.

So, our liter has 1,000 grams of mass. Grams have a relationship with moles, via the molar mass of a molecule.

We know , water molecules 18 g/mole. {16 (O)+1 (H) +1 (H) = 18.}

We then take 1,000g / 18g/mole = 55.5555 moles.

So, H2O has a molarity of 55.5