Suppose that a combustion reaction takes place under adiabatic conditions, that is, no heat is exchanged with the surroundings. In this case, the temperature of the system will increase, and the final temperature is called the adiabatic flame temperature. One relatively simple way to estimate this temperature is to suppose that the reaction occurs at the initial temperature of the reactants and then determine to what temperature the products can be raised by the quantity . Calculate the adiabatic flame temperature if one mole of CH4(g) is burned in two moles of O2(g) at an initial temperature of 298 K. Assume that the combustion occurs at constant pressure according to the reaction:
CH4(g) +2O2(g)---->CO2(g) + 2H2O(g)
Data:
ΔH=-802.2 kJ mol-1 at 298 K
Assume that the molar heat capacities for the gases are approximately given by the following expressions:
Cp[CH4(g)]/R = 2.099 + (7.272*10^-3 K^-1)T
Cp[O2(g)]/R = 3.094+ (1.561*10^-3 K^-1)T
Cp[CO2(g)]/R = 2.593 + (7.661*10^-3 K^-1)T
Cp[H2O(g)]/R = 3.652 + (1.156*10^-3 K^-1)T