1. DO NOW: Convert 450 mm Hg to atm. Convert 0.675 atm to kPa.
Convert 743 K to ⁰C.
A 500 mL metal cylinder holding moles of helium gas is known to rupture at a pressure of 10 atmospheres. At what temperature, in °C, will the container fail?

2. Dalton’s Law of Partial Pressures
Notes
Unit: Gas Laws
Dalton’s Law of Partial Pressures

3. After today you will be able to…
Describe Dalton’s law of partial pressures and calculate Ptotal or a partial pressure

4. Recall, gas pressure results from collisions of gas particles.
Gas pressure depends on the amount of gas and the KE of its particles.
Since particles in a mixture of gases at the same temperature contain the same average KE, the kind of particle is unimportant.

5. Example: Composition of Dry Air
Component
Volume
Partial Pressure
Nitrogen
78.08%
79.11 kPa
Oxygen
20.95%
21.22 kPa
Carbon dioxide
0.04%
0.04 kPa
MISC gases
0.93%
0.95 kPa
Total
100.00%
kPa

6. “The total pressure of a mixture of gases is equal to the sum of the individual (partial) pressures.”

7. Dalton’s Law of Partial Pressures
Units of pressure must match!
Ptotal= P1 + P2 + P3…

8. Example: Dalton’s Law
What is the total pressure for a mixture of O2 and CO2 if PO2= atm and PCO2= 423mmHg. PO2= 0.719atm PCO2= 423mmHg
760mmHg x =
546mmHg
1atm
Ptotal=546mmHg + 423mmHg
Ptotal=969mmHg

9. Questions? Complete WS