Okay, I've been working on this for a while: Three-tenths mole of an ideal gas at 400K is expanded isothermally from a pressure of 5x10^5 N/m^2 to 1.5x10^5N/m^2. If the gas is then heated to 500K at constant volume and then is compressed isothermally back to 5x10^5 N/m^2, and then isobarically back to the original condition, find the net work of the cycle. I understand the whole concept of expanding and contracting, but combining the ways that these happen is very confusing to me. first i found the volume for the first part using the formula V = nRT/P. so for the first part, when its expanded isothermally i used the formula: w = nRTln(V2/V1) w= (3/10)*(8.314)*(400)*ln(6.65*10^-3/2*10^-3) = 1198.68 same for the second isothermic expansion, except the temperature changed to 500, and therefrore the volume changed and: w = -1503.58 then for the third part, i used the formula for isobaric gas: w = P(V2 - V1) = 245 Then for the net work, I added everything together, and got -364.8 What am I missing here?? Thanks!