1. The problem statement, all variables and given/known data Suppose 161 moles of a monatomic ideal gas undergoes an isothermal expansion as shown in the figure (attached). The horizontal axis is marked in increments on 20 m3 What is the temperature at the beginning and at the end of this process? 2. Relevant equations PV = nRT 3. The attempt at a solution Pi = 400 kPa Vi = 20 m3 Pf = 100 kPa Vf = 80 m3 T = (PV)/(nR) = (400*20)/(161*8.31) = 5.98 K My answer is wrong according to the online homework grading system. What am I doing wrong? Any help is appreciated.