1. Pre-AP 5/9 Turn in the “gases make me happy” HW
Pick up FOUR PIECES OF BLANK PAPER and a calculator
Have a seat in your assigned seat.
You need to fold the four pieces of paper in half, staple them like a book, and label the pages (bottom corner)
We will start gases today (after we discuss test results). You will keep the gas book throughout the entire unit (you will turn it in for a grade before the test). If you are taking AP Chem next year, I suggest NOT throwing this away. I am shortening the gas unit next year to give us more time on other topics.
HW: will be determined today
FYI: I will not see 4th period Friday, so I am going to try and get you ahead today. 

2. AP 5/9
You will have all class today to work on your take home test or your career project.
If you don’t have to do either of those things, study for other classes. Your English AP test is tomorrow.
FYI: your field trip permission slip is do May 17th
FYI: You will present the career presentation May 22nd-May 24th
FYI: Your take home test is due May 17th.

3. Characteristics of Gases
The Kinetic-Molecular Theory of Matter
Pressure
The Gas Laws

4. The Kinetic-Molecular Theory of Matter

5. Kinetic-Molecular Theory of Matter
Developed to account for the behavior of the atoms and molecules that make up matter
Based on the idea that the particles of matter are always in motion

6. Kinetic-Molecular Theory of Gases
Describes the behavior of an ideal gas
An imaginary gas that perfectly fits all the assumptions of the KM theory
Based on 5 assumptions: Particles in an ideal gas…
have no volume.
undergo only elastic collisions.
are in constant, rapid, random, straight-line motion.
do not attract or repel each other.
have an average kinetic energy that is directly proportional to their Kelvin temperature.

7. Real Gases
A gas that does not behave according to the assumptions of the KM theory
Real gases behave most ideally
at low pressures
at high temperatures
for gases that are nonpolar

8. Pressure

9. 4 factors used to describe gases:
You must specify 4 measurable quantities to describe a gas:
Volume-liter, millileters
Temperature-must be in Kelvin
Number of molecules-moles
Pressure

10. Pressure and Force Which shoes create the most pressure?
Pressure-force per unit area on a surface
Gases exert pressure on any surface that they collide with, even the Earth.
Air pressure in measured with a barometer.
Which shoes create the most pressure?

11. Units of Pressure These are all equal to each other!
1 atm
760 mm Hg
760 torr
X 105 Pa
kPa
Be able to convert between them.

12. Pressure Conversion Example
The average atmospheric pressure in Denver, Colorado is atm. Express this pressure in (a) mm Hg and (b) kPa. a) b)

13. ALL TEMPERATURES MUST BE IN KELVIN FOR GASES
To convert from Celsius to Kelvin:
ADD 273
Example:
1. 250C to K=?
C to K=
To convert from Kelvin to Celsius:
SUBTRACT 273
Example:
1. 213K to 0C=?
K to 0C=

14. Practice: You have 15 minutes to convert the following pressure and temperature
atm into kPa
mmHg into atm
atm into kPa
kPa into torr
mmHg into torr
O C into Kelvin
O C into Kelvin
K into Celsius
K into Celsius
K into Celsius

15. Standard Temperature & Pressure
Abbreviated “STP”
Refers to
Temperature of 0° C
Pressure of 1 atm
Values are exact

16. Pre-AP 3/10
Today you will need the paper from the side table, a calculator, the Boyles and Charles Law worksheet, and your BIG GAS book (you were given Monday).
Please turn in the KMT picture from Tuesday if you haven’t already.
Today we will do a quick station review and then we will learn to calculate Boyles and Charles Law.
Tomorrow we will do a quick lab over the gas laws.

17. Pass the Gas Station Activity
There are 6 gas stations.
Four are printed for you on the front of the paper you picked up AND INCLUDE INSTRUCTIONS FOR EACH STATION.
You will have to ADD TWO to the back of your paper:
Station 5: Convert the pressure and temperatures for the questions at the station
Station 6: List the five assumptions of the Kinetic Molecular Theory

18. Pre-AP 3/11
Take out your gas book AND the Boyles/Charles Law worksheet. You also need a calculator.
I will show you how to work these today and then you will have the remainder of the period to finish the paper.

19. Pre-AP 3/21
Today you will need: a calculator, your gas law book, the charles/boyles law paper you received the week before spring break.
We will review what we have learned about gases so far.
You will then complete a review activity and work on the Charles/Boyles paper.
This week, we will finish up gas laws.

20. Draw a pic that demonstrates Boyle’s Law
Draw a pic that demonstrates Charles’s Law
A gas has a pressure of 546 torr and a volume of 5.6 L. What is the new pressure if the volume increases to 8.6 L?
The volume of a gas at 30°C is 42.5 L. If the temperature decreases to 10°C, what is the new volume?

21. The Gas Laws

22. Boyle’s Law Relates pressure and volume
Properties are inversely proportional-as pressure increases, volume decreases.
Any units may be used for pressure and volume, as long as they are the same for the 2 values.

23. Boyle’s Law Example 1
A sample of oxygen gas has a volume of 150. mL when its pressure is atm. What will the volume of the gas be at a pressure of atm if the temperature remains constant?
P1=0.947 atm
V1=150. mL
P2=0.987 atm
V2=?

24. Boyle’s Law Example 2
A helium-filled balloon contains 125 mL of gas at a pressure of torr. What pressure would the gas exert if it was allowed to expand to 135 mL?
P1=758.2 torr
V1=125 mL
P2=?
V2=760 torr

25. Charles’s Law Relates temperature and volume
Properties are directly proportional-as temperature increases, volume increases.
Any units may be used for volume, as long as they are the same for the 2 values.
Temperature values must be in Kelvin.
Video demonstration of Charles’s Law

26. Kelvin Temperature Scale
Starts at a temperature equal to °C.
Lowest temperature possible; called absolute zero
To convert between °C and K, round to 273.
K=°C
°C=K –

27. Charles’s Law Example 1
A sample of neon gas occupies a volume of 752 mL at 25°C. What volume will the gas occupy at 50°C if the pressure remains constant?
V1=752 mL
T1=25°C + 273=298 K
V2=?
T2=50°C + 273=323 K

28. Charles’s Law Example 2
A sample of nitrogen gas is contained in a piston with a freely moving cylinder. At 0.0°C, the volume of the gas is 375 mL. To what Celsius temperature must the gas be heated to occupy a volume of 500. mL?
V1=375 mL
T1=0.0°C + 273=273 K
V2=500. mL
T2=?

29. Gay-Lussac’s Law Relates temperature and pressure
Properties are directly proportional-as temperature increases, pressure increases.
Any units may be used for pressure, as long as they are the same for the 2 values.
Temperature values must be in Kelvin.

30. Gay-Lussac’s Law Example 1
At 120.°C, the pressure of a sample of nitrogen is 1.07 atm. What will the pressure be at 205°C, assuming constant volume?
P1=1.07 atm
T1=120°C + 273=393 K
P2=?
T2=205°C + 273=478 K

31. Gay-Lussac’s Law Example 2
Before a trip from New York to Boston, the pressure in an automobile tire is 1.8 atm at 20.°C. At the end of the trip, the pressure gauge reads 1.9 atm. What is the new temperature inside the tire?
P1= 1.8 atm
T1=20.°C + 273=293 K
P2=1.9 atm
T2=?

32. Pre-AP 3/22
Today you will need your gas book, the paper from the side table, a calculator, and something to write with.
Turn in your homework (Boyles/Charles law)
WE will cover combined gas law today and practice those types of problems.
Thursday we will cover the most important law (IDEAL GAS LAW)

33. Combined Gas Law Combine Boyle’s, Charles’s, and Gay-Lussac’s Laws
Relate pressure, volume, and Kelvin temperature
Any units may be used for pressure and volume as long as they are the same for the initial and final values, but temperature must be in Kelvin.

34. Combined Gas Law Example 1
The volume of a gas is 27.5 mL at 22.0°C and atm. What will the volume be at 15.0°C and atm?
P1=0.974 atm
T1=22.0°C + 273=295 K
V1=27.5 mL
P2=0.993 atm
T2=15.0°C + 273=288 K
V2=?

35. Combined Gas Law Example 2
A 700. mL gas sample at STP is compressed to a volume of 200. mL, and the temperature is increased to 30.0°C. What is the new pressure of the gas in Pa?
P1= x 105 Pa
T1=0.0°C + 273=273 K
V1=700. mL
P2=? Pa
T2=30.0°C + 273=303 K
V2=200. mL

36. Pre-AP 3/24 Turn in your Combined Gas Law HW
You will need your big gas book, a calculator, the papers from the side table, and something to write with.
WE will learn about the ideal gas law today and practice a few problems, then go to the computer lab for a simulation of this gas law.
Your HW for the weekend is the ideal gas law paper

37. Ideal Gas Law PV= nRT. P=pressure IN ATM V=volume IN LITERS
n=moles (may have to convert grams
R = L.atm/K.mol (proportionality constant)
T=temperature IN K
MOST USEFUL GAS LAW

38. Ideal gas law example 1
The gas pressure inside an aerosol can is 1.5 atm at 25oC. Assuming that the gas is ideal, what would the pressure be if the can were heated to 450oC?

39. Ideal gas law example 2
A quantity of helium gas occupies a volume of 16.5 L at 78oC and 45.6 atm. What is the volume at STP?

40. Ideal gas law example 3
A sample of hydrogen gas has a volume of 8.56 L at a temperature of o0C and a pressure of 1.5 atm. Calculate the moles of hydrogen molecules present in this gas sample

41. Ideal Gas Law example 4
A sample of methane gas that has a volume of 3.8 L at 5oC is heated to 86OC at a constant pressure. Calculate its new volume.

42. Ideal Gas Law example 5
How many moles of chlorine gas would occupy a volume of 35.5 L at a pressure of kPa and a temperature of 100. C? After determining the number of moles, calculate the number of grams of chlorine (Cl2) contained in this container?

43. Ideal Gas Law example 4
A sample of methane gas that has a volume of 3.8 L at 5oC is heated to 86OC at a constant pressure. Calculate its new volume.

44. Pre-AP 3/30
You will need the Ideal gas law worksheet, a calculator, something to write with.
WE will review the ideal gas law and then learn gas stoichiometry (it’s a tough one)
You will have a quiz on Friday over everything we have learned so far (minus gas stoichiometry). I am out that day so please be good. Your gas law test is next Thursday. We are almost finished. Your gas law book will be due next THURSDAY for some BIG GAS POINTS. DON’T lose it.

45. Gas Stoichiometry Moles  Liters of a Gas STP: use 22.4 L/ 1mol
Non-STP: use ideal gas law
Non-STP Problems
Given liters of gas?
start with ideal gas law
Looking for liters of gas?
start with stoichiometry conversion

46. GAS STOICH EXAMPLE 1
A sample of nitrogen gas has a volume of 1.75 L at STP. How many moles of N2 are present?

47. GAS STOICH EXAMPLE 2
How many liters of N2 are required to produce 115 g of NH3 at STP?

48. 2Al(s) + 6 HCl (aq)  2AlCl3 (aq) + 3 H2 (g)
GAS STOICH EXAMPLE 3
2Al(s) + 6 HCl (aq)  2AlCl3 (aq) + 3 H2 (g)
If 13.5 g of aluminum is reacted with excess hydrochloric acid in a 2.0 L bottle at 26C, what would the pressure be?

49. Pre-AP 4/4 Pick up the permission slip from the side table.
Today you will get back your quiz and will be given 15 minutes to transfer answers from the answer document to the actual quiz. You will need to show work on the quiz. We will grade the quiz afterwards.
We will also practice gas stoichiometry today. Tomorrow we will finish gas laws and then test on Thursday.
After the quiz, you will need the gas stoichiometry HW, a clean piece of paper, a calculator, and something to write with.

50. REVIEW~ Answer the following on a clean piece of paper.
A sample of hydrogen gas has a volume of 2.25 liters. How many moles is this at STP?
What volume of ammonia, NH3, is produce from 5.1 moles at STP?
How many liters of carbon dioxide produce 130 g of this gas at STP?
A sample of methane gas that has a volume of 3.8 L at 5oC is heated to 86OC at a constant pressure. Calculate its new volume.

51. Gas Stoichiometry
If you are given a reaction and you are asked to find volume at STP of a different reactant, you will use stoichiometry.
Example:
N2 + 3H2 2NH3
What volume of nitrogen at STP would be required to react with mol of hydrogen.

52. Gas Stoichiometry Example AT STP
N2 + 3H2 2NH3
What volume of nitrogen at STP would be required to react with mol of hydrogen.

53. Gas Stoichiometry Example AT STP
N2 + 3H2 2NH3
What volume of nitrogen at STP would be required to react with g of hydrogen.

55. Ptotal = P1 + P2 + ... Dalton’s Law
The total pressure of a mixture of gases equals the sum of the partial pressures of the individual gases.
Ptotal = P1 + P
Total pressure in container.
Partial pressures of the gases inside the container

56. Dalton’s Law Example
A mixture of 3 gases is at a total pressure of 6.11 atm. The partial pressure of gas A is 1.68 atm; that of gas B is 3.89 atm. What is the partial pressure of gas C?
PA=1.68 atm
PB=3.89 atm
PC=? atm
PTotal=6.11 atm
The total pressure in the collection bottle is equal to the sum of the partial pressures of all gases present in the bottle.

57. Dalton’s Law with H2O vapor press.
When a H2 gas is collected by water displacement, the gas in the collection bottle is actually a mixture of H2 and water vapor.
Patm = PH2O + Pgas
Look up water-vapor pressure on p.899 if given a temperature!

58. Dalton’s Law Example 1
Hydrogen gas is collected over water at 22.5°C. Find the pressure of the dry gas if the atmospheric pressure is kPa.
PH2=? kPa
PH2O=2.72 kPa
Patm=94.4 kPa
The total pressure in the collection bottle is equal to atmospheric pressure and is a mixture of H2 and water vapor.

59. Dalton’s Law Example 2
A gas is collected over water at a temp of 35.0°C when the barometric pressure is torr. What is the partial pressure of the dry gas?
Pgas=? torr
PH2O=42.2 torr
Patm=742.0 torr
The total pressure in the collection bottle is equal to barometric pressure and is a mixture of the “gas” and water vapor.