1. The problem statement, all variables and given/known data There is a monatomic gas held at a constant pressure of P = 1.48-atm, it also has a molar mass M = 16-g/mol and density ρ =1.9 × 10-3-g·cm-3. Find the total internal energy of 1-mol of this gas. 2. Relevant equations U = Q + W E = nCvT PV = nRT 3. The attempt at a solution I have tried E = 3/2nRdT but I am unsure as to how I could use molar mass and density to find anything that can be subbed in to the equations. I tried dividing M and ρ cm-3/mol but i'm not sure were to go from there.