Thermo Question!! 1. The problem statement, all variables and given/known data CCl3F and CCl2F2 have been linked to ozone depletion in Antarctica. As of 1994, these gases were found in quantities of 261 and 509 parts per trillion (1012) by volume (World Resources Institute, World resources 1996–97). Compute the molar concentration of these gases under conditions typical of (a) the mid-latitude troposphere (10°C and 1.0 atm) and (b) the Antarctic stratosphere (200 K and 0.050 atm). 2. Relevant equations pV=nRT 3. The attempt at a solution Okay ppt is hurting my head. Basically ppt = 1ng/L CCl3F MW = 137.37 g/mol So I did (137.37 g/mol)/(251g/1x10^9L )to get mol/L But I end up getting 0.526 nL/mol.. So when I go to plug in n = pV/RT to solve for my molecular weight concentration I don't know how the units are going to cross out... because its 0.526 nL/mol.. Can I just multiply 0.526(1x10^-9nL= to get L? Or is that against multiplication rules. I've never really dealt with ppt.