In: Physics
Express partial molar temperature and partial molar pressure in terms of temperature and pressure of the mixture. Explain your result
The total pressure of a mixture of gases equals the sum of the pressures that each would exert if it were present alone."
Ptotal = P1 + P2 + . . . Pn
However, there is an unavoidable problem. The gas saturates with water vapor and now the total pressure inside the bottle is the sum of two pressures - the gas itself and the added water vapor.
WE DO NOT WANT THE WATER VAPOR PRESSURE.
So we get rid of it by subtraction.
Pdry gas = Ptotal - Pwater vapor
This means we must get the water vapor pressure from somewhere.
We get it from a table because the water vapor pressure depends only on the temperature, NOT how big the container is or the pressure of the other gas.
The most useful partial molar quantity is the partial molar free energy Gi,pm. It is so useful that it is given the name of chemical potential and a separate sumbol