Calculating Heat Over a Cycle: Q, dU, W

[mneox]

Homework Statement

How much heat is added over this cycle? During which processes?
What is the heat expelled from d to a?

Homework Equations

http://img838.imageshack.us/img838/6270/29494670.png
(Goes clockwise, abcda)

The Attempt at a Solution

I'm just generally confused overall about this question. Is heat added in the processes which are going "forward"? So would heat only be added during processes a-b and b-c?

And would I use Q = dU + W to calculate the heat added for the processes?

For the 2nd question, for heat expelled, would I still just use Q = dU + W to find it?
So Q = nCvdT + pdV to find the heat expelled for process d to a.

Thanks for any clarification and help, I am really lost here.

 

[mneox]

Anyone?

 

[Redbelly98]

Hi. Yes, you would use Q = ΔU + W to get the heat added or expelled for each path segment. Q is positive for heat added, and negative when heat is expelled.

 

[Andrew Mason]

How does the temperature at c compare to the temperature at b? Use that to determine the heat flow from b-c.

How is the net work done by the system related to the heat in and heat out?

AM