Question

calculate- (a)no. of atoms present in 4 gms of hydrogen gas
(b)no. of cations present in 3 moles of sodium sulphide

Answer 1

Dear student

No of mole = 6.023 ËŸ 10²³ atoms/ cation / molecule

In every molecule, there are two atoms, so the no. of atoms present in 1 mole of hydrogen gas will be
2 ËŸ 6.023 ËŸ 10²³ ( Avogadro no.) = 12.046 ËŸ 10²³

no. of moles = atomic mass/molecular mass
= 4/2
= 2
so no of atoms in 2 mole of hydrogen gas will be = 2ËŸ12.046 ËŸ 10²³
= 24.08 ËŸ 10²³

b). No. of cation present in 1 mole of sodium sulphide Na₂S = 2 ËŸ 6.023 ËŸ 10²³ = 12.046 ËŸ 10²³
No. of cation present in 3 mole of Na₂S will be 3 ËŸ 12.046 ËŸ 10²³ = 36.13 ËŸ 10²³

Regards