The heat of combustion of ethane gas is 368 kcal / mol. Assuming that 60 % of the heat is useful, how many m 3 of ethane measured at STP must be burnt to supply enough heat to convert 50 kg of water at 10° C to steam at 100° C ? (Specific heat of water is 1 cal / g, heat of vaporisation of H 2 O is 540 cal / g )

Question

The heat of combustion of ethane gas is 368 kcal / mol. Assuming that 60 % of the heat is useful, how many m 3 of ethane measured at STP must be burnt to supply enough heat to convert 50 kg of water at 10° C to steam at 100° C ? (Specific heat of water is 1 cal / g, heat of vaporisation of H 2 O is 540 cal / g ) (A) 2.196 m 3 (B) 1.196 m 3 (C) 4.196 m 3 (D) 3.196 m 3

Tardigrade Admin · Accepted Answer

Δ H needed for change =Δ H text heating +Δ H text vaporisation =50 × 103 × 1 ×(100-10)° C +540 × 50 × 103 =31500 × 103 cal Δ H actually needed =(31500 × 103 × 100/60) (Since only 60 % of heat is used to do so) Now 368 × 103 cal heat is given on combustion by 22.4 litre ∴ (31500 × 103 × 100/60) heat is given by =(22.4 × 31500 × 103 × 100/60 × 368 × 103) =3.196 × 103 text litre =3.196 m 3

$2.196 m^{3}$

$1.196 m^{3}$

$4.196 m^{3}$

$3.196 m^{3}$

2.196m3

1.196m3

4.196m3

3.196m3

$2.196 m^{3}$

$1.196 m^{3}$

$4.196 m^{3}$

$3.196 m^{3}$