Change in Internal Energy

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Devon 1L
Posts: 16
Joined: Fri Sep 25, 2015 3:00 am

Change in Internal Energy

Postby Devon 1L » Sun Jan 10, 2016 3:56 pm

A gas sample in a cylinder is supplied with 524 kJ of energy as heat. At the same time, a piston compresses the gas, doing 340 kJ of work. What is the change in internal energy of the gas during this process?

Dorin Coffler 1J
Posts: 20
Joined: Fri Sep 25, 2015 3:00 am

Re: Change in Internal Energy

Postby Dorin Coffler 1J » Sun Jan 10, 2016 4:02 pm

The gas sample in the cylinder is supplied with 524 kJ of energy, so this is added energy. A piston compressing the gas is also added energy to the system. Therefore you must add both the energy changes given, resulting with an internal energy change of 864 kJ.

005384106
Posts: 101
Joined: Sat Aug 24, 2019 12:16 am

Re: Change in Internal Energy

Postby 005384106 » Tue Feb 04, 2020 1:20 pm

will we ever need to do any conversions for units? do these problems always need to be in kJ?

vanessas0123
Posts: 100
Joined: Wed Sep 11, 2019 12:17 am

Re: Change in Internal Energy

Postby vanessas0123 » Wed Feb 05, 2020 5:01 pm

Because q and w are both in kilojoules, you don't need to do anything with the units!

Luc Zelissen 1K
Posts: 57
Joined: Mon Jun 17, 2019 7:23 am

Re: Change in Internal Energy

Postby Luc Zelissen 1K » Wed Feb 05, 2020 11:56 pm

005384106 wrote:will we ever need to do any conversions for units? do these problems always need to be in kJ?

I assume that you will need to do unit conversions on the test to get the answer right. Its always easier to use the units that are in the questions.


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