1. The problem statement, all variables and given/known data Find the volume of 2 kg of ethylene at 270 K, 2500 kPa using Z 2. Relevant equations Method to Solve for Z, Using Tr and Pr PV = ZnRT 3. The attempt at a solution Tr = 0.9561 Pr = 0.496 Z found to be approx. 0.75 R given on a table at 0.2964 kJ/kg K From here, I should have all information needed, I was just confused on units at this point. V = ZnRT/P V = (0.75)*(n)*(0.2964 kJ/kg K)*(270 K) / (2500 kPa) At this point, my main questions are (probably very simple): What is n, and why? My best guess: (2000 g)/(28 g/mol) = 71.43 mol What are units for P? My best guess: atm, -> 2500 kPa*24.67 atm/kPa = 61675 atm Using these numbers, I get Volume to be way too low, corrections needed somewhere. Help appreciated.