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### Heat transfer

Posted: Fri Feb 02, 2018 6:38 pm
On the last test, one of the questions was discussing whether or not heat was being transferred when a balloon filled with gas was expanded to a larger volume and lower pressure while maintaining the same temperature. I thought that it was not because the temperature was not changing, however the answer is yes, so I was just wondering why that is. Thanks!

### Re: Heat transfer

Posted: Fri Feb 02, 2018 6:57 pm
I think this person had the same question: viewtopic.php?f=130&t=26744.

I don't think I got the same question on the test, but for the situation you're describing, work would be done at least (because there's a change in volume and pressure).

### Re: Heat transfer

Posted: Sun Feb 04, 2018 6:48 pm
This is an example of an isothermal process (no heat change) where the energy lost by the system is supplemented by the energy gained in the surroundings.

### Re: Heat transfer

Posted: Sun Feb 04, 2018 6:54 pm
Heat was being transferred to make up for the energy change.

### Re: Heat transfer

Posted: Sun Feb 04, 2018 7:19 pm
I had this question on my test. My answer was that heat is being transferred, because the volume and pressure are changing. This means the energy is being altered.

### Re: Heat transfer

Posted: Mon Feb 05, 2018 12:42 pm
Same question!

### Re: Heat transfer

Posted: Mon Feb 05, 2018 2:46 pm
Heat is being transferred because pressure and volume are changing. Even though the temperature is constant, that is because the changing temperature evens out and becomes non changing even though its gaining some and losing some from the pressure and volume change.

### Re: Heat transfer

Posted: Thu Feb 08, 2018 6:07 pm
There is work being done because W=PdeltaV and there is a change in volume therefore there must be a change in work as long as its not free expansion.