The heat of combustion of ethane gas is `-368 kcal mol^(-1)`. Assuming that `60%` of heat is useful, how many `m^(3)` of ethane measured at `NTP` must be burned to supply heat to convert `50 kg` of water at `10^(@)C` to steam at `100^(@)C`?

Explanation

Heat required per gram of water
`= (90 + 540) cal = 630 cal`
Total heat needed for `50 kg` of water
`= 50 xx 10^(3) xx 630 kcal`
As the efficiency is `60%`, the acid amount of heat required
`=(50 xx 10^(3) xx 630)/(60) xx 100 = 52500 kcal`
Number of mole of ethane required to produce `52500 kcal`
`= (52500)/(368) = 142.663 mol`
Volume of `142.663` mole at `NTP = 142.663 xx 22.4`
`= 3195.65 L = 3.195 m^(3)`