1. The problem statement, all variables and given/known data What is the molecular flux of argon gas, molar mass 18 g/mol, with density 0.73 kg/m3 and temperature 300 K? Answer: 3.6×10^27 collisions/m^2s 2. Relevant equations I actually have no idea 3. The attempt at a solution I can't find any reference to molecular flux in my notes or 2 physics text books, an equation would be appreciated.