#### srecko

calculate the density of air at the temperature 15Â°C (=288K) and at the pressure 99.5 kPa. Structure of the air is: 80% of volume is nitrogen, 20% of volume is oxygen. I am having problem with this task. Is there any correlation between partial pressure and partial volume?
density(air)= ( m(N2)+m(O2) ) / V

#### skipjack

Forum Staff
Are you given the value of the universal gas constant?

#### srecko

Well, it is not given, but we are supposed to know that R= 8.314 kPa L mol-1K-1

#### skipjack

Forum Staff
Calculate the specific gas constant for the gas mixture specified in the question, so that you can then use density = pressure/(specific gas constant Ã— absolute temperature).