1. Unit A: Gases
Lundquist

2. Unit A.1
Pressure & The Kinetic Molecular Theory

3. What the what??
Crushing a can Crushing a 55 gal drum Crushing a tanker

4. Pressure A measure of how much force is pushing on a specific area
On a molecular level
Collisions with walls of the containers
At sea level there are 14lbs of air pushing down on you

5. Units of Pressure Evangelista Torricelli
Italian physicist & mathematician
Grand Duke of Tuscany attempted to raise H2O 12m but the H2O would not go above 10m
Used mercury to show that pressure is related to elevation
At sea level the mercury moved up 760mm (thus 760mmHg)
1mmHg became known as a torr

6. Units of Pressure at sea level
760mmHg = 760torr Barometer – measures atmospheric pressure

7. Manometers Invented by Otto Von Guericke
Used to determine the pressure of a closed system
If the system side goes down:
𝑃 𝑠𝑦𝑠𝑡𝑒𝑚 = 𝑃 𝑎𝑡𝑚𝑜𝑠𝑝ℎ𝑒𝑟𝑒 +𝛥ℎ
If the system side goes up:
𝑃 𝑠𝑦𝑠𝑡𝑒𝑚 = 𝑃 𝑎𝑡𝑚𝑜𝑠𝑝ℎ𝑒𝑟𝑒 −𝛥ℎ

8. Units of Pressure Blaise Pascal French mathematician
Replicated Torricelli’s experiment
Was interested in the vacuum
Something that shouldn’t exist
Decided that some form of air pressure was holding the mercury up
Used newtons (force) per square meter (area) to describe air pressure
1N/m2 = 1Pa  very little

9. Units of Pressure at sea level
760mmHg = 760torr = 101.3kPa

10. Units of Pressure Conférence Générale des Poids et Mesures
General conference on weights and measurements
50’s everyone was using different units (very confusing)
Agreed that the pressure at sea level in Paris, France would forever be 1 atm

11. Units of Pressure at sea level
760mmHg = 760torr = 101.3kPa = 1atm

12. Units of Pressure are on your formula sheet!!!!

13. Practice 760mmHg = 760torr = 101.3kPa = 1atm

14. Unit A.1 Note quiz questions1.
𝑅= 𝐿•𝑎𝑡𝑚 𝐾•𝑚𝑜𝑙
atm 2.

15. I’m worth 1.6 Billion dollars, I don’t need you. You’re fired!
But first
OMG a dollar!
Not negligible
I’m worth 1.6 Billion dollars, I don’t need you. You’re fired!
Negligible

16. Vocabulary pt2 Proportional Good Grades α Happiness
increase in good grades causes an increase in happiness
Decrease in good grades causes a decrease in happiness
Inversely proportional
Coach L singing α 1/Happiness
increase in me singing causes an decrease in happiness
Decrease in me singing causes an increase in happiness

17. Kinetic-molecular theory
Explains why gases behave like they do
6 basic postulates about gases

18. Gases are made of small stuff
Gases are composed of a large number of molecules or atoms
Generally low atomic and molecular weights (bigger molecules form liquids or gases)

19. Gases are… Hello? Most of the volume of a gas is empty space.
That’s why they are easy to compress (to a point)
The volume the actual particle takes up is negligible

20. Gases and pool Always in motion
Move in straight lines, until they collide with the walls of the container or each other
These collisions with the container are called pressure
Behave like pool balls on crisco

21. Gases aren’t attractive… for the most part
There is negligible force of attraction between gas particles or between the walls of the container and the molecules (mostly)

22. Bumper cars, anyone? Collisions are elastic
Elastic Collisions -- none of the energy of a gas particle is lost when it collides with another particle or with the walls of the container.

23. Gases and heat
The temperature of a gas is an average of the kinetic energy of it’s particles
Units: Kelvin (K) = °C

24. Unit A.1 Note quiz questions4. 3.
0.5 mol
0.5 mol 5.
0.5 mol
0.5 mol

25. Kinetic-molecular theory
Deviate because of:
Attractions (IMFs)
Increase with #e-
Increase A LOT if polar (H2O, NH3, etc.)
Actually have a volume (just very small)

26. Kinetic-molecular theory
A gas that obeys all the postulates of the Kinetic Molecular Theory is called an ideal gas
Gasses are ideal at:
High temperatures
Low pressures

27. Unit A.1 Note quiz questions6. 7. 8.

28. Behaviors of a gas
𝑟𝑎𝑡𝑒= 1 𝑀𝑀

29. Diffusion

30. Effusion Rate of effusion α 1/√molar mass For comparing two gases
Ex: a balloon filled with helium will deflate faster then a balloon filled with nitrogen, B/C helium has a smaller molar mass.

31. Unit A.1 Note quiz questions9.
10.

32. Unit A.2
Gas Laws (part 1)

33. Gas Laws Daltons Law John Dalton
English Chemist, physicist, and meteorologist
Pioneered atomic theory (that Dalton)
The pressure of a system of gasses is equal to the partial pressures of the gasses in it.
𝑃 𝑇 = 𝑃 1 + 𝑃 2 + 𝑃
𝑃 𝑎 = 𝑃 𝑇 𝑚𝑜 𝑙 𝑎 𝑚𝑜 𝑙 𝑇

34. Practice

35. Water Displacement Way of collecting gas
Measures the volume of gas by the water it displaces
Water Vapor
Molecules on the surface gain energy and become a vapor
MUST be removed to get the pressure of the gas

36. Practice

37. Unit A.2 Note quiz questions1. 2. 3.

38. Shaving cream in a vacuum

39. 𝑃 1 𝑉 1 = 𝑃 2 𝑉 2 Gas Laws Boyles Law Robert Boyles
Irish natural philosopher, chemist, physicist and inventor
Pressure increases as volume decreases
Mathematically
𝑃𝑉=𝑅
𝑃 1 𝑉 1 = 𝑃 2 𝑉 2

40. Practice

41. Unit Note quiz A.2 questions4.

42. Gas laws 𝑉 1 𝑇 1 = 𝑉 2 𝑇 2 -or- 𝑉 1 𝑇 2 = 𝑉 2 𝑇 1 Charles Law
TEMPERATURE MUST BE IN KELVIN
𝑲=°𝑪+𝟐𝟕𝟑
Gas laws
Charles Law
Jacques Alexandre César Charles
French inventor, scientist, mathematician, and balloonist
Pioneered hot air ballooning (with hydrogen!)
Volume of a gas increases with temp.
Mathematically
V = RT --or-- 𝑉 𝑇 =𝑅
𝑉 1 𝑇 1 = 𝑉 2 𝑇 2 -or- 𝑉 1 𝑇 2 = 𝑉 2 𝑇 1

43. TEMPERATURE MUST BE IN KELVIN
𝑲=°𝑪+𝟐𝟕𝟑
Practice

44. Unit 8.4 Note quiz questions5. 6. 7. 8.

45. Gas Laws 𝑃 1 𝑇 1 = 𝑃 2 𝑇 2 -or- 𝑃 1 𝑇 2 = 𝑃 2 𝑇 1 Gay-Lussac’s Law
Joseph Louis Gay-Lussac
French chemist and physicist
Pressure increases with temperature
Mathematically
𝑃=𝑅𝑇 --or-- 𝑃 𝑇 =𝑅
𝑃 1 𝑇 1 = 𝑃 2 𝑇 2 -or- 𝑃 1 𝑇 2 = 𝑃 2 𝑇 1

46. Gas Laws Combined Gas Law All three at once 𝑃𝑉 𝑇 =𝑅
𝑃 1 𝑉 1 𝑇 1 = 𝑃 2 𝑉 2 𝑇 2
𝑃 1 𝑉 1 𝑇 2 = 𝑃 2 𝑉 2 𝑇 1
Before and After problems Helps with ALL the other gas laws

47. 𝑳·𝒂𝒕𝒎 𝒎𝒐𝒍·𝑲
8.31 𝑳·𝒌𝑷𝒂 𝒎𝒐𝒍·𝑲
62.4 𝑳·𝒎𝒎𝑯𝒈 𝒎𝒐𝒍·𝑲
Practice
R =

48. Unit 8.4 Note quiz questions9.
10.

49. Unit A.3
The Ideal Gas Laws

50. Which Balloon contains the most gas?
All the same 1 mol gas = 22.4 L As long as each is at the same temp, pressure and has the same volume (Avogadro’s Hypothesis) P=nR or 𝑃 𝑛 =𝑅

51. 𝑃𝑉 𝑛𝑇 =𝑅 𝑃𝑉=𝑛𝑅𝑇 ALL THE GAS LAWS
R Is a constant (the ideal gas constant)
𝐿·𝑎𝑡𝑚 𝑚𝑜𝑙·𝐾
8.31 𝐿·𝑘𝑃𝑎 𝑚𝑜𝑙·𝐾
62.4 𝐿·𝑚𝑚𝐻𝑔 𝑚𝑜𝑙·𝐾
𝑃𝑉 𝑛𝑇 =𝑅 𝑃𝑉=𝑛𝑅𝑇

52. The Ideal Gas Law Pv=nRT
𝑳·𝒂𝒕𝒎 𝒎𝒐𝒍·𝑲
8.31 𝑳·𝒌𝑷𝒂 𝒎𝒐𝒍·𝑲
62.4 𝑳·𝒎𝒎𝑯𝒈 𝒎𝒐𝒍·𝑲
The Ideal Gas Law Pv=nRT
R =

53. 𝑳·𝒂𝒕𝒎 𝒎𝒐𝒍·𝑲
8.31 𝑳·𝒌𝑷𝒂 𝒎𝒐𝒍·𝑲
62.4 𝑳·𝒎𝒎𝑯𝒈 𝒎𝒐𝒍·𝑲
Practice
R =

54. Unit A.3 Note quiz questions1.
This is saying that 0.33mol of CO2 (g) is made 2.

55. Unit A.3 Note quiz questions3.
This is saying that mol O2 is produced 4.
FREE SPACE  don’t put anything 

56. Deviations from the Ideal Gas Law
Gasses are ideal at:
High temperatures
Low pressures
Why?
IMFs do exist
Molecules do have a volume

57. Unit A.3 Note quiz questions5. 6. 7.

58. Molar Mass 𝑃𝑉=𝑛𝑅𝑇 𝑃𝑉= 𝑚𝑎𝑠𝑠 𝑀𝑀 𝑅𝑇 𝑃𝑉𝑀𝑀=𝑚𝑎𝑠𝑠𝑅𝑇 𝑀𝑀= 𝑚𝑎𝑠𝑠𝑅𝑇 𝑃𝑉 𝑀𝑀= 𝐷𝑅𝑇 𝑃
𝑃𝑉=𝑛𝑅𝑇 𝑃𝑉= 𝑚𝑎𝑠𝑠 𝑀𝑀 𝑅𝑇 𝑃𝑉𝑀𝑀=𝑚𝑎𝑠𝑠𝑅𝑇 𝑀𝑀= 𝑚𝑎𝑠𝑠𝑅𝑇 𝑃𝑉 𝑀𝑀= 𝐷𝑅𝑇 𝑃
The ideal gas equation can be used to find
Molar mass of a gas
Density of a gas
Molar mass kitty cat
“cats cover their P with DRT”

59. 𝑳·𝒂𝒕𝒎 𝒎𝒐𝒍·𝑲
8.31 𝑳·𝒌𝑷𝒂 𝒎𝒐𝒍·𝑲
62.4 𝑳·𝒎𝒎𝑯𝒈 𝒎𝒐𝒍·𝑲
Practice
R =

60. Unit A.3 Note quiz questions8. 9.
10.
Find the MM, which one of these answers matches it?

61. ALL THE FORMULAS 𝑃𝑉=𝑛𝑅𝑇 𝑅=0.08206 𝐿·𝑎𝑡𝑚 𝐾·𝑚𝑜𝑙
𝑃 𝑇 = 𝑃 1 + 𝑃 2 + 𝑃 𝑃 1 = 𝑃 𝑇 ( % 1
𝑃𝑉=𝑛𝑅𝑇 𝑅= 𝐿·𝑎𝑡𝑚 𝐾·𝑚𝑜𝑙
𝑀𝑀= 𝐷𝑅𝑇 𝑃
Do pages 26-29
𝑃 1 𝑉 1 𝑇 2 = 𝑃 2 𝑉 2 𝑇 1

62. Quiz & Lab next class Quiz Properties of a gas Combined gas law
Volume, temp, and pressure
Combined gas law
Ideal gas law
Lab
Molar volume of a gas
BEFORE Class
Do pre-Lab
Watch lab procedure