1. The problem statement, all variables and given/known data Containers A and B in the figure hold the same gas. The volume of B is four times the volume of A. The two containers are connected by a thin tube (negligible volume) and a valve that is closed. The gas in A is at 300 K and pressure of 1.0*105Pa. The gas in B is at 400 K and pressure of 5.0*105Pa. Heaters will maintain the temperatures of A and B even after the valve is opened. After the valve is opened, gas will flow one way or the other until A and B have equal pressure. What is this final pressure? 2. Relevant equations PV=nRT or PV=NkBT P1V1/T1 = P2V2/T2 3. The attempt at a solution I've been messing around with this question for awhile and I'm getting nowhere. My initial thought was to use P1V1/T1 = P2V2/T2 but then I realized that all of the variables are given. Since the volume and temperature of each container is fixed, in order for pressure to change, there must be a change in number of gas molecules in each container... but this is where I'm stuck. I'm not sure how to integrate and establish an equation with number of particles per container where PA=PB while taking into account their fixed volumes and temperatures.