Calculate the theoretical flame temperature for the combustion of methane burning

with $50\%$ excess air. The methane is initially at $25C.$ Assume that air contains $21\%O_2$

and $79\%N_2$ by volume. Additional data are available in Tables $2$ and $3.$

Latent heat of vaporisation of water at $298K=44000kJkmo{l}^{-1}.$