1. GT 3 Kinetic Moleculat Theory, Ideal Gas Law, Graham’s Law, Daltons Law of Partial Pressures

2. Evaluation/Assessment:
Objective:
Today I will be able to:
Construct an explanation for why a can collapses under different temperatures
Apply the kinetic molecular theory to solving Ideal Gas Law and Graham’s Law problems
Evaluation/Assessment:
Informal Assessment – Monitoring student progress and questions as the students complete the practice worksheets
Formal Assessment – Analyzing student responses to the practice worksheets and the exit ticket
Common Core Connection
Make sense of problem and persevere in solving them
Look for and express regularity in repeated reasoning

3. Lesson Sequence Evaluate: Warm – Up
Engage and Explore: Collapsing Can Demo
Explain: Ideal Gas Law
Elaborate: Ideal Gas Law Practice
Explain: Grahams Law
Elaborate: Grahams Law Practice
Evaluate: Exit Ticket

4. Warm - Up List the constant variables in the following gas laws
Boyle’s Law
Charles’ Law
Gay-Lussac’s Law
What is STP?

5. Objective Today I will be able to:
Construct an explanation for why a can collapses under different temperatures
Apply the kinetic molecular theory to solving Ideal Gas Law and Graham’s Law problems

6. Homework
Finish Classwork
Gases Exam
Thursday, March 27

7. Agenda Warm – Up Collapsing Can Demo Ideal Gas Law Notes
Ideal Gas Law Practice
Grahams Law Notes
Grahams Law Practice
Exit Ticket

8. Collapsing Can Demo Watch Ms. Ose’s Demonstration
With a group construct an explanation for what is occurring inside the can (5 minutes)
Share the explanation with the class

9. Kinetic Molecular Theory, Ideal Gas Law

10. Kinetic Molecular Theory of Gases
Gases consist of small particles, either atoms or molecules, that have mass
Gas particles must be separated from each other by relatively large distances
- While gases do have volume, that volume is considered to be zero, which is why we say the volume of a gases’ container is the volume of the gas

11. Kinetic Molecular Theory of Gases
Gas particles must be in constant, straight-line, rapid motion
- Explains why when you spray a bottle of perfume at one end of the room, the people at the other end are able to smell it right away
- Gases diffuse rapidly

12. Kinetic Molecular Theory of Gases
Gases exert pressure because their particles collide with the walls of the container
-Think about blowing up a balloon – the balloon blows up evenly because gas particles are hitting all points of the inside walls the same

13. Kinetic Molecular Theory of Gases
Gas particles exert no force on one another – they neither attract or repel
- It is true enough for our class

14. Kinetic Molecular Theory of Gases
Gas particles may collide with each other, but these collisions are assumed to be elastic
- Think about playing pool – you transfer kinetic energy from your stick to the cue ball to make it move

15. Elastic vs. Inelastic Collisions
POW 8 v1 v2
elastic collision v3 v4 8
inelastic collision

16. Kinetic Molecular Theory of Gases
The average kinetic energy of the gas particles depends on the temperature of the gas
- Gas particles do not all have the same kinetic energy – some move slowly and some move very fast, but most are in between
- Explains why snow can evaporate when it is so cold outside

17. Kinetic Molecular Theory of Gases
A gas that obeys all these “rules” is called an Ideal Gas
No gas will obey all the “rules,” but some are close enough
Nonpolar gases at high temperatures and low pressure are very close

18. Ideal Gas Law PV = nRT P = pressure V = volume (use only L)
n = number of moles of gas
R = constant (.0821 atm-L/mol-K or 62.4 mmHg- L/mol-K)
T = temperature in Kelvin

19. Ideal Gas Law Practice
Complete the practice at your desk. If you have questions please ask Ms. Ose. We will review selected problems

20. Grahams Law

21. Graham’s Law
The rates of diffusion of gases at the same temperature and pressure are inversely proportional to the square roots of their molar masses
Normal language: lighter gases move through the air faster than heavier gases
Example: helium moves faster than radon

22. Graham’s Law
Diffusion – particle movement from an area of high  low concentration
Effusion – diffusion of gas particles through an opening
NET MOVEMENT
NET MOVEMENT

23. Graham’s Law
Rate = rate of diffusion or effusion – usually measured in distance/time (m/s)
M = molar mass

24. Graham’s Law
On average, carbon dioxide travels at m/s at 25.0˚C. Find the average speed of chlorine gas at 25.0˚C. Hint: put the lighter gas in the numerator
= 323 m/s

25. Grahams Law Practice
Complete the practice at your desk. If you have questions, please ask Ms. Ose. We will review selected problems

26. Dalton’s Law

27. Dalton’s Law of Partial Pressures
The sum of the pressures of all gases present in a system equals the total pressure of the system
P1 + P2 + P3 + … = Pt

28. Dalton’s Law Practice
Complete the practice at your desk. If you have questions, please ask Ms. Ose. We will review selected problems

29. Exit Ticket
Imagine that you are going on an airplane trip in an unpressurized plane. You are bringing aboard an air-filled pillow that you have inflated fully. Predict what will happen when you try to use the pillow while the plane is at cruising altitude.