1. The problem statement, all variables and given/known data Two moles of a monatomic ideal gas are at a temperature of 300K. The gas expands reversibly and isothermally to twice its original volume. Calculate the work done by the gas, the heat supplied and the change in internal energy. So: T = 300K; ΔT = 0 n = 2; R = 8.314 J K-1 mol-1 V2 = 2V1 Reversible process ⇒ work is path independent. 2. Relevant equations PV = nRT W = -PdV U = W + Q 3. The attempt at a solution PV = nRT ⇒ P = nRT / V dW = -PdV ⇒ W = - ∫ PdV = - nRT ∫ [dV / V] = nRT [ln |V2 - V1|] = nRT ln V1 This isn't very helpful as I have no actual figure for what V1 is. I've tried to come up with something based on how the work is path independent (so W = P2V2 - P1V1 = V1[P2 - P1]) but I've just confused myself, as ΔT = 0 means that P1V1 = P2V2 = nRT, so that would mean that W = 0 which isn't right. I must be going wrong with my assumptions somewhere - any pointers would be much appreciated! Edit: I'm confident that once I get past the first stumbling block & calculate the work done I can fire ahead & calculate Q and ΔU. Thanks in advance!