Acetylene gas (C2H2) at 25 ºC, 1 atm enters a reactor operating at steady state and burns completely with 140% theoretical air entering at 400 K, 1 atm. If the products leave the reactor at 1200 K and assuming air has a molar analysis of 21% O2 and 79% N2, determine: a) air fuel ratio on mass basis, b) the mass fractions of products, c) the dew point temperature, d) heat transfer per kmol of fuel.

answer: the enthalpy of the overall chemical reaction is +87.88 kj or +88 kj.

according to hess's law, the overall enthalpy of a reaction is the difference between the sum of enthalpy values of all the products and the sum of enthalpy values of all the reactants.

δh(reaction) = ∑nδh(products) - ∑nδh(reactants)

δh(reaction) = [δh +δh] - [δh]

δh(reaction) = [1(-287.02) + 1(0) ] - [1(-374.9)] kj = +87.88 kj

here, δh (pcl3) = -287.02 kj, δh(cl2) = 0, δh(pcl5) = -374.9 kj

therefore, enthalpy of the overall reaction is +87.88 kj or +88 kj.

level 4 to level 2 : ))