What is the mole/ Mass ratio for ambient air at a given Temp/ Humidity? I am trying to get a very rough calculation of a pressure increase in a turbine engine with a given increase in temperature. In the ideal gas law alternative of PV=m/M(RT), The only part of the equation I am having problems with is the (m/M) portion for ambient air and fuel in the ratio stated below. I would like to know a mole/Mass equivelency of the Air and Fuel... As constants I will establish the following: Air mass= .5kg. Fuel / Air ratio = .10235 (.051175kg) (E85), Ambient air temp =60 F/ 15.5 C, Relative Humidity =30%, Ambient air pressure 1.0332275548 kg/cm2 I would like to graph pressure increases from 600-2000 deg F. Also, help with the density calculation for the above variables?