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Re: Sulfate 'n soot kills dinos!



----- Original Message -----
From: "Steve Brusatte" <dinoland@lycos.com>

A short excourse on chemistry...

> Sulfate (SO4) can decompose into SO3 and O (ozone).

Sulfate (SO4^2-, an ion that basically can't exist in air) can (under e. g.
immense heat) decompose into SO3 (sulfur trioxide, a gas when it's hot) and
O^2- (the oxide ion); so gypsum (CaSO4) becomes SO3 and CaO. (Under such
conditions SO3 is unstable and decomposes immediately into SO2, sulfur
dioxide, and O2, oxygen; but when it's cold this reaction reverses, so all
that doesn't matter in the long run.)
        Ozone is O3, not O; O is atomic oxygen that won't stay atomic
outside of a good vacuum.

> The SO3 can then combine with water to form sulfuric acid, which is "acid
rain."

Yep. (That goes fast -- a non-drop of 12 water molecules is enough according
to theoretical models.)

> [...] the sulfur from the coal combines with oxygen to form SO2, which
then combines with another oxygen molecule to form two molecules of SO3.
More chemistry.

correct

> >What is the length of time sulfate remains aloft compared to dust?
>
> I don't know for sure, but I would think that sulfate could remain in the
air longer than dust, as dust is ostensibly solid and quite heavy compared
with much of the gas in the atmosphere.

But SO3 respectively H2SO4 are beautifully soluble in water, so they're
washed out fast. Unless the impact is strong enough to blast them above the
troposphere, I suppose (and it certainly was).