Example 30.1 Calculating the maximum available work When 1.000 mol CH,0, (glucose) is oxidized to carbon dioxide and water at 25C according to the equation CH,20 (s) +6 O2(g) 6 CO2(g) +6 H,O(1) calorimetric measurements give 4 U =-2808 kJ mol-l and 4,39 +182.45 K-mol-1 at 25C. How much of this energy change can be extracted as (a) heat at constant pressure, (b) work? Sole Method We know that the heat released at constant pressure is equal to the value of AH, so we need to relate A, H to 4,0 which is given. To do so, we suppose that all the gases involved are perfect, and use eqn 2B.4 (AH=AU+An RT) in the form 4H=4U+Av,RT. For the maximum work available from the process we use eqn 3C.13