1. The problem statement, all variables and given/known data The mass of liquid nitrogen in an open beaker is found to have decreased by 46.3 g in 10 minutes. If the s.l.h of vaporisation of nitrogen at its boiling point is 1.99 x 105, at what rate were the surroundings heating the beaker? Why is the heat capacity of the beaker irrelevant? 2. Relevant equations E = mc delta T E = m l 3. The attempt at a solution I am fine with the numerical answer but can't figure out the last part of the question. I would have thought that the specific heat capacity is relevant. I first thought it was irrelevant because the beaker and liquid nitrogen would be at the same temperature but then I thought surely the beaker must be at a higher temperature than the liquid nitrogen inside otherwise there would be no flow of heat? Also it must be higher because the temperature of the surroundings is higher again there would be a flow of heat to the beaker so the beaker's temperature must be changing?