I'm kinda stuck with these problems... can somebody plz help? 1) What is the average distance between nitrogen molecules at STP? I know that at STP: T=273K, P=1atm=1.013 x 10^5 N/m^2. How would I start solving this proble? 2) The lowest pressure attainable using the best available vacuum techniques is about 10^-12 N/m^2. At such a pressure, how many molecules are there per cm^3 at 0 degree Celsius? I think you use the Ideal Gas Law: PV=NkT but then how would u get the amount of molecules?