posted by Steven . My teacher gave us the answer to a chemistry problem and i cannot figure out how she got the answer. Can you help me work out this problem so i can better understand it. A gas under an initial pressure of 0.60atm is compressed at a constant temperature from 27L to 3.0L. The final pressure will become? (5.4atm) (how did she get this answer?) P1V1 = P2V20.60*27 = P2*3.0P2 = 0.60*27/3.0 = 5.4 atm.