1. The problem statement, all variables and given/known data Rooms A and B are the same size and are connected by an open door. Room A however, is warmer(perhaps because its windows face the sun). Which room containks the grater mass of air? explain carefully. 2. Relevant equations PV=nRT, PV=NkT, N=Na*n 3. The attempt at a solution Va=Vb=V. The problem didn't mention it but I am also going to assume both rooms have the same pressure, which is the atmospheric pressure. I think the key factor that will determine which room will have the larger mass is the number of moles, since you can multiply the number of moles by the molar mass to get the mass of a molecule or compound. Am I correct?