From: Roy Mayeda (roy_mayeda@isd743.k12.mn.us)
Date: Tue Sep 10 2002 - 10:58:52 PDT
Date: 10 Sep 2002 12:58:52 -0500 Message-ID: <-1180459775roy_mayeda@isd743.k12.mn.us> From: Roy Mayeda <roy_mayeda@isd743.k12.mn.us> Subject: Re: Pinhole Digest #1004 - 09/09/02
Not sure about the polystyrene boards.
As far as the density of gases, it depends on the temperature and pressure of the gases, as well as the identity of the gases. The basic formula is density = (molar mass of gas X pressure) / (gas constant X temperature). If you give the molar mass in grams/mole (number is the same as the molecular weight), the pressure in atmospheres, and the temperature in kelvins (degrees C + 273), then the appropriate gas constant would be 0.0821 L*atm/K*mol. Specifically, for carbon dioxide at 1 atm and 20 C, the density would be about 1.8 g/L. Air is mostly a mixture of nitrogen and oxygen. If we go with a mix of 80/20 (close), we have a weighted average molar mass of 28.8 g/mol, and a density of about 1.2 g/L under the same conditions. Obviously, this will be influenced by actual composition. Hope this helps.
Roy Mayeda
(Gone, but still causing trouble.)
Sauk Centre HS
Sauk Centre, MN
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