View Full Version : Anyone know stoichiometry???

December 28th, 2008, 06:55 AM
My lecturer wants us to use microsoft excel to create a spreadsheet showing the following data for a list of 244 different chemicals:

1) the stiochiometric fuel:air ratio
2) the % of fuel (by volume) in a stoichiometric fuel : air mixture
3) stoichiometric fuel : air ratio (by mass)

I also need to show the:
empirical chemical formulae and molecular mass for each chemical

I just dont get how i'm to do it. I understood the lecture he gave on stiochiometry at the time but now its german to me and i've tried going back to him for help but he's very busy.

Can any of you please help?!?!? :confused:

December 28th, 2008, 03:21 PM

January 1st, 2009, 12:18 AM
care to be a little more specific?

January 1st, 2009, 10:02 PM
it is generally considered to be 12:1. This is variable though and is dependent upon the fuel and the compression ratios as well as spark lead.

January 1st, 2009, 10:04 PM

that sounds like a bitch

January 1st, 2009, 10:06 PM
Nah, just old hot rodders knowledge. That and a major in power and automotive.;)

January 1st, 2009, 11:29 PM
Gasoline, 14.7-1.


I think the op was talking about stoich in the automotive sense though.

January 2nd, 2009, 07:01 AM
Yeah, 14.7 : 1 is the ideal, but that would require a steady state engine. An engine operating at a fixed rpm in a consistent barometric pressure at a consistent elevation. This is one of the reasons the automotive industry is always yelling about new more demanding standards on fuel mileage. The ratio has to become lower (richer) to start, accelerate, climb hills, or operate at increased elevations. It must also become richer with an increase in heat. Diesel engines are able to operate more efficiently than gasoline engines because they do not have the variables of spark control and are totally reliant on heat, where as gasoline engines begin detonation with increases in heat and must therefor enrich the mixture to cool the combustion.

Damn, I am sounding off Sorry.

January 3rd, 2009, 08:00 AM
Ok I need it in a purely chemical analysis. Its for my fire investigation module.

January 3rd, 2009, 08:23 AM
Can't help in fire investigation. Sorry, flame spread in a combustion chamber, evaporation of fuel in the intake, intake runner lengths and they effect they have, air flow velocities, that I know some about. I can start a good campfire though.