Calculate the number of moles in the following
(i) 28g of He (ii) He of Na. (ii) 60g of Ca
Given gram atomic mass of (i) He=4g (ii) Na=23g (iii)Ca=40g.

Explanation

`(i)"28g of He The no.of moles"=("Mass of He in grams")/("Gram atomic mass ")=(m)/(M)=((28g))/((4g))=7"mol"`
`(ii)"46g of Na The no.of moles"=("Mass of Na in grams")/("Gram atomic mass ")=(m)/(M)=((46g))/((23g))=2"mol"`
`(iii)"60g of Ca The no.of moles"=("Mass of Ca in grams")/("Gram atomic mass")=(m)/(M)=((60g))/((40g))=1.5"mol"`