[jclough]

Hello everybody,

I'm quite new to thermodynamics and I'm not sure how to go about this question.

A gas at 500K is cooled at constant volume until its pressure is halved; the pressure of the gas is then kept constant and its temperature raised back to 500K. What is the total heat supplied to the gas?

I used the following definitions of the molar heat capacities

dU = CvdT for the constant volume process and dH = CpdT for the constant pressure process

And integrating those to achieve expressions for delta U and delta H, which are equal to the heat absorbed for the respective processes, I think.
I then used the ideal gas law to find the new lower temperature (half of 600K) and the new volume (half the original).

I'm not sure then what to use to find the final answer. Also, do I have to find the work done by the gas, as part of the total heat supplied?

Thank you in advance!

[Loyal]

You are doing just fine,  just use the information you obtained to find the  :delta: U and  :delta: H for their respective cycles and then add up the results.