Calculate number of atoms in (a) 2.5 mole atoms of nitrogen (b) 8.4 of sulphur

Explanation

(a) 1 mole of atoms of nitrogen `=6.023 xx 10^(23)` atoms
`therefore 2.5` mole atoms of nitrogen `=6.023 xx 10^(23)` atoms.
(b) 32 g of sulphur contain `=6.023 xx 10^(23)` atoms.
`therefore` 8.4 g of sulphur contain `=(6.023 xx 10^(23) xx 8.4)/32`
`=1.5810 xx 10^(23)`