Chemical Thermodynamics Question 393
Question: Gasoline has an enthalpy of combustion 24000 kJ/ gallon. When gasoline burns in an automobile engine, approximately 30% of the energy released is used to produce mechanical work. The remainder is lost as heat transfer to the engine’s cooling system. As a start on estimating how much heat transfer is required, calculate what mass of water could be heated from $ 25{}^\circ C $ to $ 75{}^\circ C $ by the combustion of 1.0 gallon of gasoline in an automobile- (Given: $ C(H_2O)=4.18J/{{g}^{{}^\circ }}C $ )
Options:
A) 34.45 kg
B) 80.383 kg
C) 22 kg
D) 224 kg
Show Answer
Answer:
Correct Answer: B
Solution:
- $ q=m\times c\times \Delta T,m=q/( c\times \Delta T ) $
$ =(24\times 10^{6}\times 0.7)/(4.18\times 50) $
$ =80383gor80.383kg $
