# What is the molar volume of gas at S.T.P. and S.A.T.P.?

1. Jul 27, 2012

### tasnim rahman

What is the molar volume of gas at S.T.P. (standard temperature and pressure) and S.A.T.P.(standard ambient temperature and pressure)? I googled the one for S.T.P. and found it to be 24.414L for 1 atm standard pressure, but whereas in Wikipedia it is mentioned that IUPAC recommended the standard pressure to be 100kPa at S.T.P., most websites refer to 1 atm as the standard pressure. The one for S.A.T.P. is more elusive and different websites give different conditions and molar gas volumes. Any help, or reference to threads, websites, etc, is welcome.

2. Jul 27, 2012

### jbriggs444

Why not solve PV=nRT for V, using the value of 8.3144621(75) for R and your chosen temperature and pressure.

For 1 mole at a pressure of 100kPa and a temperature of 273.15 Kelvins I get...

V = nRT/P = 1 * 8.314462175 * 273.15 / 100,000 = .02271095 cubic meters = 22.7 liters.

Mind you, I'm just an idiot using Google and what I learned in chemistry class a few decades ago.

3. Jul 28, 2012

### tasnim rahman

Thanks, but I know how to calculate from the ideal gas equation. What I don't know is what are the exact conditions for S.T.P. and S.A.T.P.? Anyone any ideas?

4. Jul 29, 2012

### nasu

The attribute "exact" is meaningless here. These are standards, so they are conventional, arbitrary. If there are several standards, as you found out, none is more (or less) exact than another.
Just use the one that applies in your field of activity.