1. The problem statement, all variables and given/known data The question ask to find the final temperature of methane gas that is heated so that its volume increases by 50% using the ideal gas law, and the compressability. The initial conditions are temperature is 300K and pressure is 8MPa. The system is isobaric. 2. Relevant equations P1V1/T1=P2V2/T2 Vr=V(ideal)/R(methane)Tcr/Pcr Pr=P/Pcr 3. The attempt at a solution The ideal gas solution was easy, an increase of 50% on the volume while the pressure remains constant results in an increase in the temperature by 50%. However when I use the compressability charts I run into the problem where my Pr and Vr do not intersect on the compressability graph at medium pressures.My Pr is 1.72 and My Vr=7.1. Clearly I am doing somthing wrong, and I could use any help anyone has to offer. Thanks.