Question

calculate the molarity of water if its density is 1000 kg/m3

Answer 1

density of water is at 20 C = 0.9982071 gram /ml
let we take 1 liter water
1 liter = 1000 ml
mass of 1 liter water = volume *density
= 1000 ml * 0.9982071 gram /ml
= 998.2071 gram

molar mass of water H2O = 2* 1.008 + 15.999
= 18.015 gram / moles

number of moles of water in one liter
= mass of substance / molar mass
= 998.2071 gram/18.015 (gram / moles)
=55.41 moles

molarity of water = number of moles of water / volume of water
= 55.41 moles/ 1liter
= 55.41moles/liter
Answer:- molarity of water at 20 C is

Answer 2

Hey !!

Molarity of water means number of moles of water in 1 litre of water.

1 L of water = 1000 cm³ = 1000 g        ( ∵ d = 1000 kg/m³ = 1 g/cm³ )

     1000 g of H₂O = $\frac{1000}{18} moles = 55.56$ moles

Here, Molarity = 55.56 M

GOOD LUCK !!