1. The problem statement, all variables and given/known data Atoms of the inert gas Krypton are adsorbed onto a smooth solid surface at 90K. They can move freely over the surface but they cannot leave it. For a sample with total surface area 2.5 m^2, and a surface density 3 nm-2, what is the heat capacity of the krypton? 2. Relevant equations [itex]\Delta E[/itex]/ [itex]\Delta T[/itex] = Cv ( where Cv is specific heat @ constant volume) [itex]\Delta E[/itex] = [itex]\Delta W[/itex] + [itex]\DeltaQ[/itex] U = 3/2nRT , U = 3/2NkbT 3. The attempt at a solution Data given: Krypton molecular weight : 84.8 /1000 = 0.0848 kg/mol. I believe I have an idea on how to solve this. The fact that the gases can't escape implies work done = 0, however I am a little confused by the spatial dimensions provided. Would I multiply 2.5 with 3 ? however that makes no sense to get mass. I was wondering.. could I use : Mass = Molecular weight / Avogadro's number and then plug in: Moles = mass/mr to give me 'n' which I could plug into U = 3/2nRT Is my approach sensible ?