## 8.13 - Understanding the Solution

$w=-P\Delta V$
and
$w=-\int_{V_{1}}^{V_{2}}PdV=-nRTln\frac{V_{2}}{V_{1}}$

MCracchiolo 1C
Posts: 55
Joined: Sat Jul 22, 2017 3:00 am

### 8.13 - Understanding the Solution

For question 8.13, "In a combustion cylinder, the total energy change produced from the burning of a fuel is -2573 kJ. The cooling system that surrounds the cylinder absorbs 947 kJ as heat. How much work can be done by the fuel in the cylinder?"

The answer, 1626 kJ...Is that the amount of expansion work done by the combustion? And do you subtract the 947 kJ because the cylinder is trying to cool the reaction?

Nancy Le - 1F
Posts: 52
Joined: Fri Sep 29, 2017 7:07 am

### Re: 8.13 - Understanding the Solution

947kJ should be positive because the system is absorbing the heat in order to cool down, which means it's an endothermic process. Work done by the system produces a negative work value.

Christine Wastila 1H
Posts: 61
Joined: Fri Sep 29, 2017 7:04 am

### Re: 8.13 - Understanding the Solution

The answer, 1626 kJ refers to how much work can be done by the fuel in the cylinder. You subtract 947 kJ because this amount of energy was lost to the surroundings as heat.