The document describes the key properties and laws relating to gases. It discusses: 1) Kinetic molecular theory which describes how gas particles behave as having no volume, undergoing elastic collisions, and moving in random straight lines without attracting or repelling each other. 2) Real gases which differ in that particles have volume and can attract each other. Gases behave most ideally at low pressure, high temperature, and for nonpolar molecules. 3) Characteristics of gases such as expanding to fill their container due to random motion and low density. Gases can also be compressed, undergo diffusion and effusion. 4) Important gas laws including Boyle's law relating inverse relationship between pressure and volume at constant

1. I. Physical
Properties
9 (A) describe and calculate the relations
between volume, pressure, number of moles,
and temperature for an ideal gas as described
by Boyle's law, Charles' law, Avogadro's law,
Dalton's law of partial pressure, and the ideal
gas law;
9 (B) perform stoichiometric calculations,
including determination of mass and volume
relationships between reactants and products
for reactions involving gases; and
9 (C) describe the postulates of kinetic
molecular theory.
Gases

2. 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.

3. B. Real Gases
❂ Particles in a REAL gas…
• have their own volume
• attract each other
❂ Gas behavior is most ideal…
• at low pressures
• at high temperatures
• in nonpolar atoms/molecules

4. 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

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

6. D. Temperature
ºF
ºC
K
-459 32 212
-273 0 100
0 273 373
( )32FC 9
5
-°=° K = ºC + 273
❂ Always use absolute temperature
(Kelvin) when working with gases.

7. E. Pressure
area
force
pressure =
Which shoes create the most pressure?

8. E. Pressure
❂ Barometer
• measures atmospheric pressure
Mercury Barometer
Aneroid Barometer

9. E. Pressure
❂ Manometer
• measures contained gas pressure
U-tube Manometer Bourdon-tube gauge

10. E. Pressure
2
m
N
kPa =
❂ KEY UNITS AT SEA LEVEL
101.325 kPa (kilopascal)
1 atm
760 mm Hg
760 torr
14.7 psi

11. F. STP
Standard Temperature & Pressure
0°C 273 K
1 atm 101.325 kPa
-OR-
STP

12. II. The Gas
Laws
BOYLES
CHARLES
GAY-
LUSSAC
Ch. 12 - Gases

13. A. Boyle’s Law
P
V
PV = k
Volume
(mL)
Pressure
(torr)
P·V
(mL·torr)
10.0 760.0 7.60 x 103
20.0 379.6 7.59 x 103
30.0 253.2 7.60 x 103
40.0 191.0 7.64 x 103

14. A. Boyle’s Law
❂ The pressure and volume
of a gas are inversely
related
• at constant mass & temp
P
V
PV = k

15. A. Boyle’s Law

16. k
T
V
=V
T
B. Charles’ Law
Volume
(mL)
Temperature
(K)
V/T
(mL/K)
40.0 273.2 0.146
44.0 298.2 0.148
47.7 323.2 0.148
51.3 348.2 0.147

17. k
T
V
=V
T
B. Charles’ Law
❂ The volume and absolute
temperature (K) of a gas
are directly related
• at constant mass &
pressure

18. B. Charles’ Law