Question

What is the number of nitrogen atoms in 66 g of (NH4)2SO4? [Avogadro's constant= 6.02 x 10^23 mol-1 ; Molar mass of (NH4)2SO4 = 132 g mol-1]

Answer 1

(NH4)2SO4 = 36 + 32 + 64 =132

no. of moles = wt/mol.wt = 66/132 = 0.5

1 molecule contains 2 atoms of nitrogen.

no. of atomic moles of nitrogen = 2 x 0.5 = 1 mole.

we know that 1 mole contains 6.023 x 10^23 no.of atoms of N