13/14 Semester 2
Physical Chemistry I
(TKK-2246)
Instructor: Rama Oktavian
Email: rama.oktavian86@gmail.com
Office Hr.: M.13-15, Tu. 13-15, W. 13-15, Th. 13-15, F. 09-11
Outlines
1. Dalton’s law
2. Partial pressure
Dalton’s law
Ideal gas law for gas mixture
We define the partial pressure of each gas in the mixture as the pressure the
gas would exert if it were alone in the container of volume V at temperature T
Dalton’s law
Partial pressure
Dalton’s law
Dalton’s law
Dalton’s Law of Partial Pressures indicates
that
• pressure depends on the total number of gas
particles, not on the types of particles.
• the total pressure exerted by gases in a
mixture is the sum of the partial pressures of
those gases.
PT = P1 + P2 + P3 +.....
Dalton’s law
Dalton’s law
Partial pressures are simply related to the mole fractions of the gases
in the mixture
p1 n1 RT V

p nt RT V
Dalton’s law
Partial pressures are simply related to the mole fractions of the gases
in the mixture
Dalton’s law
Learning check
If I place 3 moles of N2 and 4 moles of O2 in a 35 L container at a temperature
of 25°C, what will the pressure of the resulting mixture of gases be?
What’s the partial pressure of carbon dioxide in a container that holds 5
moles of carbon dioxide, 3 moles of nitrogen, and 1 mole of hydrogen and
has a total pressure of 1.05 atm?
Dalton’s law
Learning check
A vessel of volume 22.4 dm3contains 1.5 mol H2and 2.5 mol N2 at
273.15 K. Calculate (a) the mole fractions of each component, (b) their
partial pressures, and (c) their total pressure
Dalton’s law
Dalton’s law application in atmosphere
This explains why people usually difficult to breathe in high altitude place
even the concentration of oxygen is same (21%)
The transfer of oxygen molecules from the lungs to the bloodstream is
dependent on a pressure gradient.