1. KINETIC MOLECULAR THEORY

2. Phase Changes Requiring Energy

3. Melting The process by which a solid becomes a liquid
The melting point is the temperature at which the solid becomes a liquid

4. Melting

5. Vaporization The process by which a liquid changes to a gas or vapor
Evaporation is vaporization that occurs only on the surface of a liquid
Vapor Pressure is the pressure of vapor above a liquid
As heat is added to a liquid the vapor pressure increases
The Boiling Point is the temperature at which vapor pressure is equal to atmospheric pressure

6. Vaporization

7. Sublimation
The process by which a solid changes directly into a gas

8. Phase Changes that Release Energy

9. Freezing The process by which liquid becomes a solid
The freezing point is the temperature at which a liquid becomes solid

10. Freezing

11. Condensation
The process by which gas becomes liquid

12. Condensation

13. Deposition
The process by which vapor turns to a solid without moving through a liquid phase

14. Phase Diagrams
The triple point is the temperature and pressure at which all three phases can exist at once
The critical point is the temperature and pressure above which the substance can only exist as a gas

15. States/Phases of Matter

16. Solids Most ordered state of matter
Strong attractive forces between particles
Definite shape
Fixed volume
Particles in constant vibrational motion

17. Liquids Less ordered than solids, but more ordered than gasses
Some attractive forces between particles
Able to take the shape of the container
Fixed volume
Constantly in fluid motion, meaning they flow about freely

18. Gasses Very disordered Behavior of gasses is described by the
Kinetic-Molecular Theory and the
Gas Laws

19. Assumptions made by KMT
Particle Size-
gasses are made up of small particles
separated by empty space
no attractive forces between particles
Particle Motion-
constant random motion
collisions between particles are elastic, meaning kinetic energy is conserved

20. Assumptions made by KMT
Particle Energy
Kinetic Energy of a Gas Particle= ½ mass * velocity2
All particles of a gas have the same mass, but not the same velocity
Not all particles have the same Kinetic Energy

21. 4 Variables Affecting Gasses

22. Temperature Temperature is the average kinetic energy of particles
When performing calculations, it is important to use the Kelvin scale
Conversion Factor:
°C = Kelvin (K)
Note that NO DEGREE SYMBOL is used with Kelvin

23. Volume
Volume is the space occupied by an “object” (an object can be solid, liquid, or gas
Conversion Factor:
1L = 1000mL = 1000cm3

24. Pressure Pressure is the force per unit area Conversion Factor:
1ATM = 760mmHg = 101.3kPa = 14.7psi

25. mole Number of Particles
The unit used to talk about the number of particles is the
mole
Conversion Factor: for any given substance,
1 mole=molar mass

26. Standard Temperature and Pressure
STP
0 Kelvin
1 atmosphere of Pressure

27. Diffusion/Effusion
Diffusion is the movement of gas particles from an area of greater concentration to an area of lower concentration (down a concentration gradient)
Effusion is diffusion through a small opening

28. Graham’s Law of Effusion
Graham’s Law states that the rate of effusion of a gas is inversely proportional to the square root of its molecular weight
Equation for Graham’s Law:
Is used to compare the effusion/diffusion rates for two gasses
Heavier particles diffuse more slowly

29. Example 1:
Ammonia (NH3) has a molar mass of 17.0g/mole; hydrogen chloride (HCl) has a molar mass of 36.5g/mole. What is the ratio their diffusion rates?

30. Example 2:
What is the rate of effusion for a gas that has a molar mass twice that of a gas that effuses at a rate 3.6mol/min?

31. Example 3:
Calculate the molar mass of a gas that has a rate of effusion four times that of CO2.

32. Dalton’s Law of Partial Pressures
Each gas in a mixture exerts pressure independently of the other gasses present
Dalton’s Law states that the total pressure of a mixture of gasses is equal to the sum of the pressures of all the gasses in the mixture
Ptotal = P1 + P2 + P3 + … Pn

33. Example 1:
Find the total pressure for a mixture that contains four gasses with a partial pressure of 5.00kPa, 4.56kPa, 3.02kPa, and 1.20kPa.

34. Example 2:
A mixture of oxygen (O2), carbon dioxide (CO2) and nitrogen (N2) has a total pressure of 0.97 atm. What is the partial pressure of O2 if the partial pressure of CO2 is 0.70 atm and the partial pressure of N2 is 0.12 atm?

35. The Gas Laws

36. Relationships Between Variables

37. Pressure and Volume Graph Direct or Inverse?
Description: one goes up, the other goes down
Mathematical Formula: P1V1=P2V2
Gas Law: Boyle’s Law
Pressure
Volume

38. Pressure and Temperature
Graph
Direct or Inverse?
Description: one goes up, the other goes up
Mathematical Formula: P1/T1 = P2/T2
Gas Law: Charles’s Law
Temperature
Pressure

39. Volume and Temperature
Graph
Direct or Inverse?
Description: one goes up, the other goes up
Mathematical Formula: V1/T1 = V2/T2
Gas Law: Gay-Lussac’s Law
Temperature
Volume

40. The Combined Gas Law
The combined gas law states the relationship among pressure, volume, and temperature of a fixed amount of gas
Equation for the Combined Gas Law:
*where temperature MUST be in KELVIN
Or simplified:

41. Example 1:
A gas at 110kPa and 30.0°C fills a flexible container with an initial volume of 2.00L. If the temperature is raised to 80.0°C and the pressure increased to 440kPa, what is the new volume?

42. Example 2:
A helium-filled balloon at sea level has a volume of 2.1L at atm and 36°C. If it is released and rises to an elevation at which the pressure is atm and the temperature is 28°C, what will be the new volume of the balloon?

43. Example 3:
A sample of helium gas in a balloon is compressed from 4.0L to 2.5 L. If the pressure of the gas in the 4.0L volume is 210kPa, what will the pressure be at 2.5L?

44. Example 4:
The volume of a gas at 99.0kPa is 300.0mL. If the pressure is increased to 188kPa, what will the new volume be?

45. Example 5:
A gas sample at 40.0 °C occupies a volume of L. If the temperature is raised to 75.0 °C, what will be volume be, assuming the pressure remains constant?

46. Example 6:
A gas at 89°C occupies a volume of 0.67L. At what Celsius temperature will the volume be increased to 1.12L?

47. Example 7:
The pressure of a gas in a tank is 3.20 atm at 22.0°C. If the temperature rises to 60.0°C, what will be the gas pressure in the tank?

48. Example 8:
A gas in a sealed container has a pressure of 125kPa at a temperature of 30°C. If the pressure in the container is increased to 20kPa, what is the new temperature?

49. Avogadro’s Principle and Molar Volume

50. Avogadro’s Principle
Avogadro’s principle states that equal volumes of gasses at the same temperature and pressure contain equal number of particles
One mole = x 1023 particles

51. Molar Volume
The molar volume of a gas is the volume that one mole of a gas occupies at standard temperature and pressure
STP= 1atm of pressure, 0 Kelvin
The molar volume for any gas at STP is 22.4L
Conversion factor: L /1 mole
This conversion factor can be used to find…
The number of moles in a gas sample
The mass of a gas sample
The number of particles in a gas sample

52. Example 1:
Calculate the volume that moles of a gas will occupy at STP.

53. Example 2:
Calculate the volume that 2000g of methane gas (CH4) will occupy at STP.

54. Ideal Gas Law
The ideal gas law describes the physical behavior of an ideal gas in terms of the pressure, volume, temperature, and number of moles of gas present
Equation for the Ideal Gas Law:
Where…
P= pressure (MUST be in ATM)
V= volume (MUST be in LITERS)
n= # of moles
R= ideal gas constant, ( L*atm/mol*K)
T= temperature (MUST be in KELVIN)

55. Example 1:
If the pressure exerted by a gas at 25°C in a volume of 0.044L is 3.81 atm, how many moles are present in the gas?

56. Example 2:
Determine the Celcius temperature of 2.49 moles of gas contained in a 1.00L vessel at a pressure of 143kPa.

57. Example 3:
Calculate the volume of a mol sample of gas will occupy at 265K and a pressure of 0.900atm.