what is the gas constant (R) for mm Hg?

8.31 is for atm
.08206 is for kPa
right?

3 answers

You have them reversed.
0.08205 for atm
8.31 for kPa.
Then my teacher is messed up. So, for mm Hg it would be...?

By the way, Happy Halloween!!!!!
If you have pressure listed in mm mercury, change to atm by dividing by 760 mm/1 atm, then use R as 0.08206 L*atm/mol*K. If pressure is in kPa, use R as 8.3145 J/mol*K (kPa*L/mol*K).
Pressure in mm Hg may be changed to kPa by multiplying mm Hg x 0.13332 and using R of 8.1345 BUT I've not seen that done. You can try this yourself.
PV = nRT
Let's have P = 760 mm, V = 22.415 L, n = 1, R =?? and T = 273.15 K.

Solve for R.
R = PV/nT = (760/760)*22.415/1*273.15 = 0.08206

Let P = 101.325 kPa, V = 22.415 L, n = 1, R = ??, and T = 273.15 K.
R = 101.325*22.415/1*273.15 = 8.315

Let P = 760 mm, V = 22.415 L, n = 1, R = ?? and T = 273.15 K.
R = 760*22.415*0.13332/1*273.15 = 8.315

Here is a site that talks a little more about it but the conversion from mm Hg to kPa is not listed. http://en.wikipedia.org/wiki/Gas_constant