1. Science Starter (Week 12, Day 4, 4/22/16)
Draw the graphs representing the relationship between pressure and temperature, pressure and volume, and pressure and number of particles.
1atm = 760torr = kpa = 760mmHg = 14.7 psi
Convert 1030 torr to atm.
Convert 0.34 psi to mmHg.
Convert 2340 mmHg to 760 torr.
Describe what happens to a sample of gaseous carbon dioxide as you increase temperature.

2. Objective
SWBAT use the combined gas law to determine changes in pressure, volume, and temperature of gases

3. Agenda
Science Starter
Recap the Lab
Combined Gas Law
Practice

4. Recap from Yesterday
When the # of particles increases, pressure increases When temperature increases, Pressure increases When volume increases, Pressure decreases

5. 55-Gallon Drum Crushing

6. Kinetic Molecular Theory: Particles of a gas…
are in constant motion
experience elastic collisions
do not stick to other particles.
Increase speed with temperature.
The pressure of a gas is related to the frequency and impact of the collisions of the gas particles

7. 3x = (10)(6) 2) 2x = 5(10) 4 20 Quick Reminder
Please solve for x in the following 2 problems below your Science Starter!
3x = (10)(6)
2) 2x = 5(10)

8. Unit 6: Gas Laws Combined Gas Law

9. Notes: Combined Gas Law
Four variables used in gas law problems:
V =
T =
n =
P =

10. Notes: Combined Gas Law
Four variables used in gas law problems:
V = volume of the gas (L)
T = temperature (K)
K stands for Kelvin.
K = oC+273
n = number of particles (moles)
P = pressure (atmospheres)

11. Notes: Combined Gas Law
Earlier, we found the relationship between all these variables. 1) Pressure and Temperature are POSITIVELY related (when one goes up, so does the other). 2) Pressure and the number of particles (n) are POSITIVELY related. 3) Pressure and volume are NEGATIVELY related (when one goes up, the other goes down)!!

12. What does this all boil down to?
THE COMBINED GAS LAW!!!
ALERT!!
T must ALWAYS be in Degrees KELVIN
(celsius +273)

13. Process of solving a problem
Step 1: Identify the given variables of the problem
For some problems this will be easy, but you really have to look through word problems!!
Clues—First: initial, beginning, start
Clues—Second: then, secondly, after, new
Look for the verb! If something is happening, you have a __________ then ___________ situation.
Step 2: Cross out any variables you don’t need
Step 3: Solve the remaining equation

14. Examples
The pressure inside of a 5.1 L container is 3.2 atm. The container expands to a volume of 8.8 L. What is the new pressure inside the balloon?
P1 = 3.2 atm V1 = 5.1 L P2 = ? V2 = 8.8 L
Step 1: Identify which variables the problem gives you.
Step 2: Cross out any variables you don’t need
Step 3: Solve the remaining equation

15. You must convert to Kelvin!!!
Examples
Bria has a 3.2L balloon of hydrogen gas at 23 C. She leaves the balloon in her blazing hot car, and the temperature increases to 72 C. What is the new volume of the balloon?
V1 = 3.2 L T1= 23 C V2 = ? T2 = 72 C
You must convert to Kelvin!!!

16. Partner Practice
The pressure inside a .83 L hot air balloon is 4.31 atm. If the volume increases to 1.44 L, what is the new pressure inside the balloon? P1 = 4.31 atm V1 = .83 L P2 = ? V2 = 1.44 L

17. Example – Word Problems
A sample of xenon gas in a 6.1 L container initially has a pressure of .85 atm. If the pressure of the gas increased to 1.9 atm, what is the new volume of the container?
Step 1: Identify which variables the problem gives you.
CIRCLE KEY FACTS. CROSS OUT EVERYTHING YOU DON’T NEED.
Step 2: Cross out any variables you don’t need
Step 3: Solve the remaining equation

18. Examples
In a thermonuclear device, the pressure of liters of gas within a bomb casing reaches 4,000,000 atm. When the explosion destroys the bomb casing, the gas is released into the atmosphere where it reaches a pressure of atm. What is the volume of the gas after the explosion.

19. Partner Practice
Synthetic diamonds can be manufactured at pressures of 60,000 atm. If we took 2.0 liters of gas at 1.0 atm and compressed it to a pressure of 60,000 atm, what would the volume be?

20. Practice Stations 4 questions around the room
Answer each on a sheet of paper
Turn in to the bin for today’s exit ticket!
(Show your work, write the number, and circle answer!!)

21. Partner Practice
A sample of gas occupies of volume of 5.5 L. After being compressed to a volume of 3.9 L, the new temperature of the sample of gas is 273 K. What was the initial temperature of the gas?
V1 = 5.5 L T1= ? V2 = 3.9 L T2 = 273K

22. Example
The temperature inside my refrigerator is about 40 Celsius. If I place a balloon in my fridge that initially has a temperature of 220 C, a volume of 0.5 liters, and a pressure of 3 atm, what will be the volume of the balloon when the pressure decreases to 2 atm and the temperature decreases to 40 Celsius?

23. Partner Practice
The pressure in a 3.0L bicycle tire is 2.08 atm at 25˚C in Fresno. You take the bicycle up to Huntington, where the temperature is 0oC. The tire shrinks to a volume of 2.0 L. What is the final pressure in the tire?
V1 = 3.0 L T1=250 C P1= atm
V2 = 2.0 L T2 = 00 C P2=?

24. Partner Practice
A sample of gas at 288 K occupies a volume of 52.9 L. The gas is compressed to a volume of 41.9 L. What is the new temperature of the gas?