1. The problem statement, all variables and given/known data A hot air balloon has a volume of 2000m^3, and air is always at atmospheric pressure due to large opening. What is the mass of the air if the temp is 120*c. Assume a molecular weight of 28.8g/mol for the air) 2. Relevant equations PV=nrt 3. The attempt at a solution I don't really have one, my class notes on this section are not clear, and the instructor was gone but still expected us to learn it. I don't get it. Please help, this is due tonight at midnight my whole grade hangs in the balance.