1. I. Physical Properties (p. 303 - 312)
Ch. 10 & 11 - Gases
I. Physical Properties (p )

2. The Kinetic-Molecular Theory of Matter
Used to explain the properties of gases, liquids and solids in terms of:
1) Energy of particles
2) Forces acting between particles.
Kinetic Theory is based on the idea that particles of matter are in constant motion and that this motion has consequences.

3. The Kinetic-Molecular Theory of Gases
Ideal Gas - Imaginary gas that conforms perfectly to all assumptions of the Kinetic Theory.

4. A. Kinetic Molecular Theory
Particles in an ideal gas…
have no volume.
have elastic collisions.
are in constant, random, straight-line motion.
don’t attract or repel each other.
have an avg. KE directly related to Kelvin temperature.

5. B. Real Gases Particles in a REAL gas… have their own volume
attract each other, therefore collisions are not elastic (slowed down)
Avg KE still directly related to Kelvin Temp

6. Real gas Gas behavior is most ideal… at low pressures
at high temperatures
in nonpolar atoms/molecules

7. The Kinetic Theory and the Nature of Gases
The Kinetic Theory accounts for the following physical properties of gases:
Expansion - gases do not have a definite shape nor definite volume, they fill the container they are in.
Fluidity - There is very little attraction between gaseous particles, they flow past each other.
Low Density - Most of a gas is empty space. The same amount of a gas as a liquid/solid takes up 100% more space.

8. Compressibility - because there is so much space between molecules in a gas they can be crowded closer together.
Diffusion - spontaneous mixing of 2 substances due to random motion.
A) Rate of Diffusion - depends upon
1) speed of molecules
2) size
3) attractive forces
Effusion gas particles under pressure pass through a very small hole from one container to another.
A) Rate of Effusion - is directly proportional to the velocity of the particles.

9. C. Characteristics of Gases
Gases expand to fill any container.
random motion, no attraction
Gases are fluids (like liquids).
no attraction
Gases have very low densities.
no volume = lots of empty space

10. C. Characteristics of Gases
Gases can be compressed.
no volume = lots of empty space
Gases undergo diffusion & effusion.
random motion

11. 10.2 Qualitative Description of Gases
To describe gases accurately, you must use 4 measureable quantities;
1. Temperature
2. Pressure
3. Volume
4. Quantity or # of Particles

12. Temperature Scales a) Celsius - developed by Anders Celsius(1701-1744)
- 0oC freezing pt. of water
- 37oC body temperature
- 100oC boiling pt. of water
- 20oC normal room temperature
b) Fahrenheit - developed by inventor of Mercury thermometer - Gabriel Daniel Fahrenheit in 1714.
- 32oF freezing pt. of water
- 98.6oF body temperature
- 212o F boiling pt. of water
c) Kelvin - developed by William Thomson, Lord Kelvin.
- K, Kelvin is the SI unit of Temperature
- 0 K, Zero Kelvin - Absolute Zero
- 273 K freezing pt. of water
- 373 K boiling pt. of water

13. D. Temperature
Always use absolute temperature (Kelvin) when working with gases. ºF ºC K
-459 32
212
-273
100
273
373
K = ºC + 273

14. E. Pressure
Which shoes create the most pressure?

15. E. Pressure Barometer measures atmospheric pressure Aneroid Barometer
Mercury Barometer
Aneroid Barometer

16. E. Pressure Manometer measures contained gas pressure U-tube Manometer
Bourdon-tube gauge

17. E. Pressure KEY UNITS AT SEA LEVEL 101.325 kPa (kilopascal)
1 atm = 30 in. Hg
760 mm Hg
760 torr
14.7 psi

18. VOLUME Volume- amount of space an object takes up
Solid – L x W x H, cm3
Fluid(Gas/Liquid)
-- Graduated Cylinder in ml
Quantity/# of Particles – measured
in moles(6.022 x 1023 particles)

19. Standard Temperature & Pressure
F. STP
STP
Standard Temperature & Pressure
0°C K
1 atm mm
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