Question is:

Compare the stoichiometric air/fuel ratios (AFR) for complete combustion of benzene (C6H6), octane (C8H18), and ethanol (C2H5OH) in air (O2 + 3.76N2). The only products should be CO2, H2O, and N2. Calculate both volumetric and mass AFR.

I haven't had chemistry in a long time. I can't remember how to do this. Help me remember how? I think it was pretty easy...

...pi r round...cornbread r square

write the balanced equations for combustion of benzene/octane/ethanol

pretty sure you can ignore the N2 for this (seombody correct me if im wrong)

so for benzene:

2C6H6 + 15O2 --> 12CO2 + 6H2O

so you have the stoichiometry - work out mass and volume (google the density to calculate volume)

divide o2 / hydrocarbon should give you the answer


edit: ive never encountered this style question before but that is how i would do it..

This post was edited by ArnoldChlamydia on Jan 29 2014 09:41pm

Very close, air is roughly 21% oxygen by mole, you need to take that into account since it asked for air instead of fuel.