1. The problem statement, all variables and given/known data I have been tasked with designing a feasible experiment to determine the ration between 2 vessels. I think i have a way that works on paper. 2. Relevant equations pV = nRT and the conservation of mass. 3. The attempt at a solution 1.Start with 2 vessels of unknown volume x and y. they are linked with a pipe/valve. the temp in x to start is t1(x) and in y is t1(y). the catch is, im keeping the pressure constant, so p(x) and p(y). This is the crucial idea, as im going to increase the temperature of one to say, t3(x) leading to t4(y) being produced in the y vessel. I can use the conservation of mass so n(initial sum) = n(final sum) for moles, and rearrange to find x/y. However, is it a feasible procedure, does it work the way i would want it to? could i keep the pressure constant? im not sure how... We did it with an isothermal process, and have to justify using another process to find the same result. regards, james.