Ethylene undergoes combustion according to the thermochemical equation : C_(2)H_(4)(g)+3O_(2)(g) to 2CO_(2)(g)+2H_(2)O(l), DeltaH^(@)=-337 kcal Assuming 70% efficiency, how much water at 20^(@) C can be converted into steam at 100^(@)C by the combustion of 10^(3) litres of C_(2)H_(4) gas at NTP ?

Ethylene undergoes combustion according to the thermochemical equation

1.	Ethylene undergoes combustion according to the thermochemical equation : C_(2)H_(4)(g)+3O_(2)(g) to 2CO_(2)(g)+2H_(2)O(l), DeltaH^(@)=-337 kcal Assuming 70% efficiency, how much water at 20^(@) C can be converted into steam at 100^(@)C by the combustion of 10^(3) litres of C_(2)H_(4) gas at NTP ?
Answer» SOLUTION :Mole of `C_(2)H_(4)=(1000)/(22.4)=44.6` Total heat evolved `=44.6xx337=1.5xx10^(4)"KCAL"` `:.`useful heat `=0.7xx1.5xx10^(4)=1.05xx10^(4)"kcal"` Now, WATER evaporation TAKES place in two stages: `H_(2)O(1,20^(@)C) to H_(2)O(1,100^(@)C),DeltaH=80"kcal//kg"` and `H_(2)(1,100^(@)C) to H_(2)O(g,110^(@)C),DeltaH=540 "kcal//kg"` `:. H_(2)O(1,20^(@)C) to H_(2)O(g,100^(@)C),DeltaH=620"kcal//kg"` `:.` weight of water converted to steam `("amount of heat available")/("heat requiredper kg")` `=(1.05xx10^(4))/(620)=16.9kg`