As we all know, the air we breath is made up of appox... 78% Nitrogen ... 21% Oxygen ... and then traces of other random things. Lets consider that only the oxygen and nitrogen exist so that we neglect the other chemical traces. If I were to fire up a compressor that pumps outside air into a container. we raise the pressure of the container until eventually the pressure stops to increase because the gas starts to form a liquid. But how does there being two chemicals effect the pressure of the tank. does one of the chemicals start to become a liquid but the vapor pressure of the tank continue to rise until the next chemical can become a liquid? Out of all of the chemicals considered to be in the air (Nitrogen, Oxygen, Neon, Argon, CO2...etc.) What will become a liquid first at 20 degrees celcius?