The IE1 and IE2 of Mg. (g) are 740 and 1450 kJ mol-1. Calculate the percentage of Mg+ (g) and Mg2+ (g) if 1 g of Mg (g) absorbs 50 kJ of energy.
No. of moies of Mg vapours present in I g = 124 = 0.0147 Energy absorbed to convèrt Mg (g) to Mg+ (g) = 0.0417 × 740 =30.83 kJ Energy left unused = 50 – 30.83 = 19.17 kJ Now 19.17 kJ will be used to e Mg+ (g) to Mg2+ (g) . ∴ No. of moles of Mg+ (g) converted to Mg2+ (g) = 19.171450 = 0.132 %age of Mg+ (g) = 0.02850.0417 × 100 = 68.35 and %age of Mg2+ (g) = 100 – 68.35 = 31.65
