Re: Chemical Reaction Energy Release and Propellants

From: Stirling Westrup (
Date: Sat Feb 05 2000 - 17:55:41 MST

Robert J. Bradbury wrote:

> > Sarcasm mode on... >
> Jeepers, I can't believe this group, how come you don't all have
> Physical Chemistry books on your desk? I'm surprised you can even
> survive in this world... After all its the basis for life itself...

Actually, I *do* have a rather nifty organic chemistry book on my desk, and
every couple of months I try once again to get through the first few chapters.
I dunno, but relativity and nuclear physics always seemed easier than organic
chem when I was in university...

> And then what is it with these lazy asses, god it seems like they
> are multiplying. Aren't they supposed to be sterile? Even if not,
> shouldn't there be some selection affect against their long term
> survival?

Being a lazy ass is actively selected for, especially when there are dupes
around that you can convince to do the work for you ;-p

> > Sarcasm mode off... >
> Reaction heats of fusion:
> Reaction DeltaHf (kJ/mole)
> H2 + F2 --> 2HF -271 (*2)
> 2H2 + O2 -> 2H2O -286 (*2)
> C + O2 --> CO2 -394
> 4Fe + 3O2 --> 2Fe2O3 -824 (*2)
> 3Fe + 2O2 --> Fe3O4 -1184
> 2Ca + 2C + 3O2 --> CaCO3 -1207 (*2)
> 2Al + 3O2 --> Al2O3 -1675
> 12C + 11H2O --> sucrose -2222
> 4P + 5O2 --> P4O10 -2984
> Obviously its difficult to make some of these reactions happen
> exactly as outlined, but I think they make clear a point.
> The most energy gets generated when you collapse the greatest
> number of molecules into most highly constrained compound.
> I.e. most of the energy isn't in the bonds but in the motion
> of individual molecules (i.e. the entropy). Ideally what you
> want is something that would take two gases and generate
> a solid (since the energy in the molecular motion of the
> gases has to be released). Lacking that, the Fe/Al reactions
> seem nice since one of the reactants is a gas and the result
> is a solid.

Nifty! And something which I would never have guessed at. Thanks for the chart
and the insight!

 Stirling Westrup  |  Use of the Internet by this poster       |  is not to be construed as a tacit
                   |  endorsement of Western Technological
                   |  Civilization or its appurtenances.

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