(Solved): Acetylene (C2H2) can be burned either with pure oxygen or with alr. The standard enthalpy of ...

Acetylene $$\left({\mathrm{C}}_2{\mathrm{H}}_2\right)$$ can be burned either with pure oxygen or with alr. The standard enthalpy of combustion of acetylene, is $$?1056.5\mathrm{MJ}/\mathrm{kmol}$$. Assume the composition of air is $$79\%$$ Nitrogen, $$21\%$$ Oxygen by volume. (a) Determine the stoichiometric air-fuel-ratio and the stoichiometric oxygen-fuel ratio for burning acetylene, in either of the above two modes, by volume. (b) Assuming a reasonable approximation to the mean value of $$C_P$$ for the products, and both the acetylene and oxygen entering the combustion process at an initial temperature of Tin $$=298\mathrm{K}$$, estimate the adiabatic flame temperature if the acetylene is burned with an equivalent ratio of $$0.909$$ in pure oxygen. Calculate the percentage concentration of the products of the combustion. (c) Briefly explain why the adiabatic temperature calculated in (b) above could never be reached by burning acetylene with air even if the AFR was stoichiometric. Briefly indicate how molecular dissociation would have affected the estimate you found in (b) above. Atomic mass, $$\mathrm{C}=12,\mathrm{H}=1,\mathrm{O}=16,\mathrm{N}=14$$.