In state-of-the-art vacuum systems, pressures as low as 1.00 x 10^-9 Pa are being attained. Calculate the number of molecules in a 1.90-m^3 vessel at this pressure and a temperature of 35.0°C.

Okay. So I know I have to use the Ideal Gas Law, PV = nRT, I then transformed it into being PV/RT = n.

1.00 X 10^-9 is my P.
1.90 m^3 is my V.
308.15 K is my T. (35 degrees C + 273.15)

How do I solve for how many molecules there are? What is my R?

2 answers

the number of molucles is n*avagradro's number

R? Pressure is Pa, volume in m^3, T i Kelvins... R has to be in Pa-M^3/mole.kelvins or 8.314
Okay so my equation was set up correctly and should read.. (1.00x10^-9)(1.90m^3)/(8.314x308.15) Correct? So my R would be 2.67724^-12?