How many molecules contain in 0.40 moles of H2S ?
1 mole H2S contains = 2 moles of H or 2 X 6.023 x 10 23 atoms .
.4 mol contains = .4 x 2 x 6.023 x 10 23 atoms.
Similarly, 1 mole H2S contains = 1 mole of S = 6.023 X 10 23
.4 mol H2S contains = .4 x 6.023 x 10 23atoms