1. Problem Statement The problem asks to find the net work from one complete cycle A-B-C. Problem 13, starting on page 66 of the slide show here: https://engineering.purdue.edu/~xe/Files/FE%20Review/Thermo/FEThermoReview2013.pdf [Broken] 2. Relevant equations ideal gas law: PV=mRT Boyle's Law: W=RTln(v2/v1) 3. Attempt at solution I understand most of the solution, but on page 67, says that W=R*T*ln(Vb/Va) is equivalent to W=p*Va*ln(Vb/Va), assuming ideal gas and constant mass. I don't understand why you can use volume here instead of specific volume. From the ideal gas law: PV=mRT and RT=PV/m. So I thought it should be W=p*Va/m*ln(Vb/Va). Why can we eliminate m here? Thank you!