What is the formula of partial pressure?

1 Answer
May 25, 2015

For an ideal gas, the partial pressure relationship is called Henry's Law. It's just the total pressure #P_"tot"# multiplied by the mole fraction #x_j# of the mixture that is occupied by component #j#.

#P_j = x_jP_"tot"#

You're really just multiplying the total pressure by the percentage corresponding to one component. So if the total pressure was #1# atm, then if the partial pressure of component #j# is #0.8# atm, its mole fraction is #(0.8 cancel(atm))/ (1 cancel(atm)) = 0.8#.