1. The problem statement, all variables and given/known data A reversible heat engine produces work from the temperature difference that exists between a mass of m = 9 kg of an ideal gas (cv = 716 J/kgK, R = 287 J/kgK) in a rigid container and a heat reservoir at THR = 285 K. The only heat transfer interaction experienced by the container is with the heat engine. The gas in the container is initially at temperature T1 = 772 K and pressure P1 = 106 Pa. The reversible heat engine operates until the ideal gas and the heat reservoir are in thermal equilibirum (state 2). If the efficiency of the heat engine for process 1-2 can be defined as W/(QH)HE, calculate its value.Give your answer as a percent (without the % sign). 2. Relevant equations efficiency = (QH - QL)/QH = W/QH QL = MCvTHRln(T2/T1) E2 - E1 = Q1-2 - W1-2 S2 - S1 = QL/ THR - change in entropy from or to a heat reservoir QH = MCv(T2 - T1) 3. The attempt at a solution If efficiency = (QH - QL)/QH = 1 - (QL/QH) = 1 - ((THRln(T2/T1))/(T2-T1)) I get an answer of 41.683538% but unsure as to what value to use for T2? Would I just use THR (Temp of heat reservoir) seeing as it works at thermal equilibrium? I used the temperature of the reservoir as the T2 value in my solution but not sure if this is correct?