Recent content by George32

Thank you, and thanks for the help! Let's just hope I don't forget before the exams!

Yes, sorry, I got myself confused between Total energy and Internal Energy. However the rest should still stand and I'm glad you came to the same conclusions :)

Okie-Dokie. So I have a result (I think!), let's see what you think. To me it makes sense. Using the 1st law dU=dQ-dW, and the change in energy dU of the surroundings will be equal to that of the system (just in the opposite direction). Compute dW using ∫pdv and p=CV-n and rearranging to...

My value for n (polytropic exponent) came out as 1.538 (4s.f.) If you could show the process were externally reversible, then the entropy generation would have to be 0 and so entropy change of the surroundings would be equal to positive of the entropy change of the system. The issue is...

I did calculate n, I used the ideal gas law to find the volume for the second state and then used logs, but I don't see how that helps find the entropy of the surroundings? I will redo the numbers using your method to check I have the right n. Thanks for the reply! I'm using google and...

Homework Statement We have a piston in a cylinder containing Helium. The initial states are: P1=150kPa T1= 20°C V1=0.5m3 Following a polytropic process, the final states are: P2=400kPa T2=140°C V2 is unknown. We're also given R=2.0769 kPa.m3.(kg.K)-1 And Cp=5.1926kJ.(kg.K)-1 As...