1. The problem statement, all variables and given/known data Integrated circuits are manufactured in vacuum chambers in which the air pressure is 7.00×10^(−11) mm of Hg. What are (a) the number density and (b) the mean free path of a molecule? Assume T = 21.0 C. I've double checked, this is all the information available. Quoted verbatim. 2. Relevant equations 101,300 Pa = 760 mm of HG. I was able to figure the pressure in Pa. Pa = 9.33 x 10^(-9). I've seen various equations involving pressure and N (number density), but they all involve volume and other variables. p = (1/3)(N/V)(m)(v)^2 where v is the RMS velocity. I don't know the m value for "air", etc. I know N will be the number of molecules per cube meter. 3. The attempt at a solution I figured the pressure in Pa, but I don't know which formula to use when they all seem to have several unknowns. Am I missing something, or is the question not specific enough? Thanks.