1. The problem statement, all variables and given/known data A natural-gas fuel contains 85 mol-% methane, 10 mol-% ethane, and 5 mol-% nitrogen. a) What is the standard heat of combustion (kJ mol-1) of the fuel at 25°C with H2O(g) as a product? b) The fuel is supplied to a furnace with 50% excess air, both entering at 25°C. The products leave at 600°C. If combustion is complete and if no side reactions occur, how much heat (kJ mol-1 of fuel) is transferred in the furnace? 2. Relevant equations 3. The attempt at a solution For this problem, I am unsure if in general, the exiting temperature is the reaction temperature. I mean, initially the gases are at 25 C, but when they exit they are 600C. That doesn't mean it reacted at 600 C, the result of the reaction just happened to be that temperature increase, right?