I know that the gas constant used in the ideal gas law is 8.31 kPa x L/ mol x K, but does that apply to all gases? Or do some gases have different R values?
2007-01-15 10:04:02 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry
I realise that the definition says that it does not change, but my chemistry teacher hinted that it might and I was wondering about that.
2007-01-15 10:13:38 · update #1
The gas constant by definition does not change and applies to all gasses.
2007-01-15 10:09:20 · answer #1 · answered by matthew r 1 · 0⤊ 0⤋
No! Gases never have different R values. R is truly a constant. R changes only with the units applied. What changes is the equation of state. The most basic equation of state is PV = nRT. There are equations of state that I cannot reproduce here. One of them is the van der Waals equation, which is the same as PV = nRT, except that there are wan der Waals variables, P plusorminus a and V plusorminus b to make it come out according to the actual gas data. This is why some gases that are not perfect gases, behave differently.
2007-01-15 18:23:06 · answer #2 · answered by steve_geo1 7 · 0⤊ 0⤋
R (Rydberg's constant) is always constant.
I think your teacher or professor is referring to the different values for R in respect to the units you are using. If you are using atmosphere's R = 0.08206 atm x L/ mol x K. If you are using kilopascals, R = 8.3124 kPal x L / mol x K. Pascals and atmospheres are just 2 ways to measure pressure. Pascals is the universal form for measuring pressure 1 N/m^2. 1 atmosphere is just the pressure of air on Earth at sea level.
2007-01-15 18:40:06 · answer #3 · answered by WingIV 2 · 0⤊ 0⤋
The universal gas constant cannot change unless you use different pressure units. That is why its called universal gas constant. aIf you use atmospheres as opposed to kiloPascals the constant is approximately .0821. Is that helpful?
2007-01-15 18:13:30 · answer #4 · answered by 624787 1 · 0⤊ 0⤋