On Mon, 27 Jan 2003 10:16:00 -0500 (EST), Henry Spencer
<[EMAIL PROTECTED]> wrote:

>On Sun, 26 Jan 2003, Randall Clague wrote:
>> A mole of H2 is 2 grams?  Chem 101 is a distant memory, but that
>> doesn't ring true.  Let's see...  Wow.  H2 is so light that a mole of
>> GH2 weighs 1.9 grams at STP.  OK.  Far out.
>
>A mole of H2, in any state, weighs 2g.  More precisely, 2.01594g (twice
>hydrogen's atomic weight of 1.00797).

That's odd.  1.9 was only a BOTE, but I was expecting better accuracy
than 5%.  I used:

N atomic weight: 14
O atomic weight: 16
H2 molecular weight: 2
ICAO sea level density of air: 1.225 kg/m^3
liters per mole at STP: 22.4

to get 

air atomic weight: 14.4
H2 molar weight: 3.8 grams

then realized I use atomic weights for N and O and molecular weight
for H2.  Correction yields 1.9 g/mol.

Oh bother.  14.4 is 20% N 80% O.  With 15.6 I get...2.06 g/mol.  Still
a 3% error.

What am I doing wrong?

-R

-- "We've all heard that a million monkeys banging on a million typewriters
will eventually reproduce the entire works of Shakespeare.  Now, thanks to
the Internet, we know this is not true." -- Robert Wilensky, UC Berkeley
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