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Old 02-03-2009, 03:36 PM
dlevitt dlevitt is offline
89 300E
 
Join Date: May 2008
Location: Long Island, NY
Posts: 80
Quote:
Originally Posted by sixto View Post
Those are variations of the ideal gas law. Can ideal gas laws apply to typical air at STP and STP + 2 bar?

Volume doesn't change, temperature doesn't chage (after equalizing) and the ideal gas constant doesn't change (if it even applies) so we're down to P1/n1 = P2/n2. P1 = 1 bar absolute, P2 = 3 bar absolute. If P2/P1 = 3, n2/n1 = 3. That's how I came up with 3:1 air mass ratio. But I don't know if all the stuff before getting to the P/n ratios is valid for a non ideal gas. Nor if a mole is directly proportional to mass in this situation.

Sixto
87 300D
Ideal gas law is a good first approximation. It breaks down when the gas in the sample is near a phase change.

The 'n' is the sum of the number of moles [6.02 * 10E24 molecules] for each different kind of molecule in the gas mixture [O2 + N2 + Ar + H2O + CO2 +....]
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