Calculate the number of molecules in each of the following (a) 24 g of nitrogen (b) 8.0 g of `H_(2)S`.

Explanation

(a) molar mass of nitrogen = 28g
28 g of nitrogen contain `=6.023 xx 10^(23)` molecular
`therefore 24` g of nitrogen contain = `(6.023 xx 10^(23))/28 x 24`
`=5.162 xx 10^(23)`
(b) Molar mass of `H_(2)S = (2+32) g = 34 g`
34 g of `H_(2)S` contain `= 6.023 xx 10^(23)` molecules.