posted by Helpme on .
Forty miles above the earth's surface the temperature is 250 K and the pressure is only 0.20 mm Hg. What is the density of air (in grams per liter) at this altitude? (Assume the molar mass of air is 28.96 g/mol.)
n/V= molar desity= P/RT
mass density= molar density*molmass
Watch your units.