Question

Calculate the number of moles in 20 g of water

Answer 1

Number of moles,n=m/M where m=given mass
and M=Molar mass
So,molar mass of water(H20)=2×1+1×16=18u
Hence,n=20g/18u{m=20g(given}
=10/9
=1.11111....
Hence,number of moles in 20g of water is 1.11111......

Answer 2

Given: 20 grams of water.

To find: We have to find the number of moles.

Solution:

The formula of water is $H_2O$.

The atomic weight of H is 1 and Oxygen is 16.

Thus the molecular weight of water is 18.

Now we know that 18 grams of water occupy 1 mole.

Thus 20 grams of water will occupy 20/18=1.11 mole.

The number of moles in 20 grams of water is 1.11.