1. The problem statement, all variables and given/known data An ideal Carnot engine takes in 160 kcal of heat at 110°C and exhausts some of this at 10°C. How much work (in joules) must have been done by the engine? 2. Relevant equations The engine's efficiency is ε = (TH - TL)/TH. The hint tells me that I need to use the First Law of Thermodynamics to calculate the work, which is ∆U = Q - W. I also have the equation ε = |W|/|QT|. 3. The attempt at a solution The efficiency is (383.15 - 283.15) / 383.15 = 0.261 but how do I find QT? I converted the 160 Cal. to Joules and got 669888 J... but somehow that seems like a lot- is it right?