Maximum flame temperature during Combustion of CH4

[duchuy]

Homework Statement

Combustion of CH4 at constant pressure (P=1bar).

Relevant Equations

CH4 (g) + 2O2 (g) --> CO2 (g) + 2H2O (g)
Enthalpy of reaction = -803 kJ.mol-1

Hi, I have to calculate the maximum flame temperature of the reaction above. The answer is 4805K but I didn't manage to obtain that answer. Please help me find my error, thank you so much! The values of C are below the solution attempt.

 

[cmb]

What does a flame that you can see consist of?

 

[mjc123]

Where you have written (T_f - 298)², that should be (T_f² - 298²). Correcting this gives 4805 K. But who says this is the right answer? Why do you think they give you the heat capacity of N₂?

 

[duchuy]

Where you have written (T_f - 298)², that should be (T_f² - 298²). Correcting this gives 4805 K. But who says this is the right answer? Why do you think they give you the heat capacity of N₂?

Thank you sir! My excuses for my math. They gave the heat capacity of N2 for the following question that asks about the combustion in 20% O2 and 80% N2.
This question is for combustion in 100% O2.
But again, thank you so much for your help!
By the way, I found 2280K for the combustion in 20% O2 and 80% N2, that should be correct right?