1. You will put this stuff on a leash and own it like a dog.
Gas Class #5 OB: You will become a gas math master
You will put this stuff on a leash and own it like a dog.
What’s your dog’s name?

2. Avogadro’s Hypothesis
This is so important, it’s one slide but it’s epic thinking. You should consider putting this statement (and diagram) in a frame, and hang it in your bathroom, forever.
“Equal volumes of DIFFERENT gases, at THE SAME temperature + pressure have the SAME number of moles, and the SAME number of particles”.

3. “Equal volumes of DIFFERENT gases, at THE SAME temperature + pressure Have the SAME number of moles, and the SAME number of particles”.
NH3 He
CO2 J He
CO2
NH3
Volume
22.4 L
Temp.
273 K
Pressure
101.3 kPa
Particles
6.02 x 1023
moles
1.0 mole

4. Volume as a function of Temperature. Pressure as a function of Volume.
Draw these three graphs, casually, but correctly. Use P, V, and T for axis labels. Draw proper lines. Indicate if each graph is directly or inversely proportional.
Volume as a function of Temperature.
Pressure as a function of Volume.
Pressure as a function of Temperature.

5. Draw these three graphs, casually, but correctly
Draw these three graphs, casually, but correctly. Use P, V, and T for axis labels. Draw proper lines. Indicate if each graph is directly or inversely proportional.
Volume as a function of Temperature.
Pressure as a function of Volume.
Pressure as a function of Temperature. V P P T V T
DIRECTLY Proportional INVERSELY Proportional DIRECTLY Proportional
This one is hard to draw, but it’s a smooth curve-alicious curve

6. Convert 145.6 kPa into atmospheres

7. Convert 145.6 kPa into atmospheresX
1.0 atm kPa
= atm (4SF)

8. Convert 1.06 atm into millimeters of mercury
Change 844 mm of Hg into kilopascals

9. X = 806 mm Hg (3SF) X = 112 kPa (3SF) 1.06 atm 1 760 mm Hg 1.0 atm
Convert 1.06 atm into millimeters of mercury
Change 844 mm of Hg into kilopascals
1.06 atm 1 X
760 mm Hg 1.0 atm
= 806 mm Hg (3SF)
844 mm Hg 1 X
101.3 kPa 760 mm Hg
= 112 kPa (3SF)

10. Ideal Gases vs. Real Gases
Ideal gases do not exist, except as the idea of “perfect” gases.
Real gases are real, they are the ones you know, like N2, CO2, O2, NH3, Ne, etc.
Most real gases remain gases because of the kinetic molecular theory of gases (and the Sun’s free energy each day).
Ideal gases can’t become liquids, no matter the temperature or pressure, since they’re FAKE.
Real gases can become liquid or solid.
Real gases act most ideally under these 2 conditions:
High temperature and low pressure. Because with high temperature, they bang around so hard, they are less likely to stick together. With low pressure, they are not as likely to even bump into each other, which makes it hard to form into a liquid.

11. Ideal Gases vs. Real Gases
When comparing different real gases, at the same temperature and pressure, the gas with the smallest particles, are the most ideal.
If you had 2.45 liters of neon, of carbon dioxide, and of propane, all at STP, which would act MOST IDEAL?
Neon = single atoms = MOST IDEAL
Carbon dioxide = 3 atom molecules
Propane (C3H8) = 11 atom molecules = LEAST IDEAL

12. NOW: 54 gas problems, numbers: 22 – 33
Answers to be handed out at the end of class today.
Check over your work.
Next, last demo diagram: Pressure + Temperature

14. Heat up some water in a can with a hot plate
Demo Diagram #3 The Can Crush Pressure is directly proportional to Temperature
Water in can converts to steam with q = mHV
Steam pushes up, pushing air out of the can.
The can fills with H2O gas, at normal pressure (top is open)
Heat up some water in a can with a hot plate

15. Temperature + pressure are directly proportional
As the temperature of the steam (gas) in the can drops upon cooling (it condenses to liquid) The pressure decreases also.
Temperature + pressure are directly proportional

16. Temperature + pressure are directly proportional.
The gas cools down (all the way to a liquid). As the temperature drops, the pressure decreases as well.
Reverse: as the temperature is increased, the pressure boosts up too. (more KE = more Collisions)
Temperature as function of Pressure T
Pressure
Temperature + pressure are directly proportional.