1. Energy and States of Matter
Energy Part 1
Energy and States of Matter

2. There are four basic properties of a gas: pressure (P) volume (V)
Gas Properties
There are four basic properties of a gas:
pressure (P)
volume (V)
temperature (T)
number of particles (n)

3. Units Used for Gases Temperature Kelvin (K) (degrees Celsius + 273)
Volume
Liter (L) or milliliters (mL)
Pressure
Atmospheres (atm)
Additional Acceptable Pressure Units for Gases
& Conversions
1 atm = kiloPascals (kPa) = 760 torr = 760 mmHg

4. Temperature
Temperature is a measure of the average kinetic energy of particles
High temperature = high KE
Low temperature = low KE

5. Maxwell-Boltzmann Distribution
Distribution of Velocity
If temperature is AVERAGE kinetic energy
Particles are moving at various velocities
The higher the temperature, the larger the range of velocities

6. Mass & Speed Average kinetic energy depends on BOTH mass & speed
KE = ½ mv2
Particles of different mass must be moving at different speeds in order to have the same kinetic energy
Bowling balls!

7. Absolute Zero Absolute Zero
the temperature when a particle has no motion (really as close to no motion as possible)
On the Celsius scale:
-273℃

8. Absolute Zero IS ZERO on the Kelvin Scale
Created for measuring temperature to be directly proportional to kinetic energy of particles
Measured in Kelvins (K)
Kelvin T = Celsius T + 273

9. Converting temperature units
25°C to K
25°C = 298 K
10°C to K
10°C = 283 K
315 K to °C
315 K – 273 = 42°C
366 K to °C
366 K – 273 = 93°C

10. Kinetic Molecular Theory
Describes the behavior of matter in terms of particles in motion
Makes assumptions about gas particles
Negligible volume

11. 2. Elastic collisions
No kinetic energy is lost, only transferred between colliding particles

12. 3. No significant attractive forces between molecules
Particles are far enough apart that they do not experience significant attractions
DIFFUSION - Particles can move past one another to mix.

13. Forces of Attraction
Intermolecular forces determine a substance’s state at a given temperature
Inter- means “between”
Intermolecular forces are the forces BETWEEN molecules
Intramolecular forces
Intra- means “within”
The bonds!

14. Gas particles are in constant, random motion
They move in a straight path until they collide
EFFUSION – Particles escape through a pinhole in a container.
If a mixture of gases of different mass are all at the same temperature, do you think all gases will escape at an equal rate? Explain.

15. The Gas Laws
For a fixed amount of gas, a change either in pressure, temperature, or volume will affect the other two variables

16. Boyle’s Law
Pressure & volume are inversely proportional when temperature is constant
P1V1 = P2V2

17. Charles’s Law
Temperature & volume of a gas are directly proportional when pressure is constant = V1 T1 V2 T2

18. Gay-Lussac’s Law
Pressure and temperature are directly proportional when volume is constant = P1 T1 P2 T2

19. The volume is directly proportional to the number of gas molecules.
Avogadro’s Law
The volume is directly proportional to the number of gas molecules.
–Constant P and T
More gas molecules = larger volume
V = constant × n

20. Combined Gas Law
When pressure, temperature, and volume are all factors that change
Use this equation instead of memorizing the other three individual gas laws!

21. Dalton’s Law of Partial Pressures
The sum of the partial pressures of the components in a gas mixture equals the total pressure:
The partial pressure of a component in a gaseous mixture is its mole fraction multiplied by the total pressure

22. Practice Problem 1
A diver blows a 0.75-L air bubble 10 m under water. As it rises to the surface, the pressure goes from 2.25 atm to 1.03 atm. Will the volume of air in the bubble at the surface increase or decrease? Calculate the volume. P1
= atm P2
= 1.03 atm V1
= 0.75 L V2
= ? T1 = T2
The volume should increase because the pressure is decreasing
(2.25 atm)(0.75 L) = (1.03 atm)V2
V2 = 1.6 L

23. Practice Problem 2
A helium balloon in a closed car occupies a volume of 2.32 L at 40.0°C. If the car is parked on a hot day and the temperature inside rises to 75.0°C, assuming the pressure remains constant, do you expect the volume to increase or decrease? Calculate this volume. P1 = P2 V1
= 2.32 L V2
= ? T1 = T2 =
The volume should increase because the temperature is increasing
(2.32 L)/(313 K) = V2/(348 K)
V2 = 2.58 L

24. Practice Problem 3
The pressure of the oxygen gas inside a canister is 5.00 atm at 25.0°C. The canister is located at a camp high on Mount Everest. If the temperature falls to °C and volume is held constant, will the pressure in the canister increase or decrease? Calculate the new pressure? P1
= atm P2
= ? V1 = V2 T1
= K T2
= K
The pressure should decrease because the temperature is decreasing
(5.00 atm)/(298.0 K) = P2/(263.0 K)
P2 = 4.41 atm

25. Practice Problem 4
A gas at 110kPa and 30.0°C fills a flexible container with an initial volume of 2.00 L. If the temperature is raised to 80.0°C and the pressure increases to 440 kPa, what is the new volume? P1
= 110 kPa P2
= 440 kPa V1
= 2.00 L V2
= ? T1 = T2 =
(110 kPa)(2.00 L)
(440 kPa)(V2) =
V2 = 0.58 L
(303.0 K)
(353.0 K)