## Ch 8 Exercise 107

Ariana_Kermani_2G
Posts: 10
Joined: Fri Jul 15, 2016 3:00 am

### Ch 8 Exercise 107

A person of average mass burns about 30 KJ/minute playing tennis. Find the time you would have to spend playing tennis to burn up the energy in a 2.0 oz serving of cheese, which has a specific enthalpy of combustion of 17.0 KJ/gram.

What is the difference between specific enthalpy and specific enthalpy of combustion? And how is the enthalpy of combustion relevant to the problem?

Maya Kandah 3M
Posts: 10
Joined: Wed Sep 21, 2016 2:59 pm

### Re: Ch 8 Exercise 107

First covert ounces to grams using the conversion factor 1oz=28.35g. Then calculate the amount of energy released from the cheese by multiplying the specific enthalpy of combustion by the amount of grams. Lastly, multiply the amount of energy by 1min/30kJ to get the required time of exercise.

Hope this helps!

Annie Tagvoryan 3A
Posts: 9
Joined: Wed Sep 21, 2016 2:57 pm

### Re: Ch 8 Exercise 107

Hey Ariana,

The specific enthalpy of combustion is relevant to the problem because it describes what's occurring and I don't think it's necessarily different from specific enthalpy, it's just a type of specific enthalpy.

Best,
Annie

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