(a) Molecular Weight of Ammonia (NH3) = 14 + 3(1) = 17 g
Molecular Weight of Ammonium Sulphate ((NH4)2SO4)
= 2[14 + 4(1)] + 32 + 4(16)
= 132 g
2NH3 + H2SO4 → (NH4)2SO4
34 g 132 g
132 g of ammonium sulphate is given by 34 g of ammonia
∴ 78 g of ammonium sulphate is given by 34\over 132 × 78
= 20.09 g of ammonia
Hence, 20.09 g of ammonia gas is required.
(b) Molecular Weight of Ammonium Chloride (NH4Cl)
= 14 + 4(1) + 35.5
= 53.5 g
2NH4Cl + Ca(OH)2 → CaCl2 + 2H2O + 2NH3
107 g 34 g
107 g of ammonium chloride gives 34 g of ammonia
∴ 32.6 g of ammonium chloride will give 34\over 107 × 32.6
= 10.36 g of ammonia
Hence, 10.36 g of ammonia gas is obtained.