Friday, Jan. 18 th : “A” Day Tuesday, Jan. 22 nd : “B” Day Agenda

2. Friday, Jan. 18th: “A” DayTuesday, Jan. 22nd: “B” DayAgenda • Homework questions/collect (Pg. 432: #1-12) • 2nd combined gas law example for warm-up • Sec. 12.2 quiz: “The Gas Laws” • Lab discussion/write up: “Charles’ Law: The Effect of Temperature on Volume” • Gas Laws and Drinking Straw Activity Lab next time - dress appropriately!

3. Homework QuestionsPg. 432: #1-12 • Questions/Problems? • Hand In

4. Additional Example A gas at STP occupies 28 cm3 of space. If the pressure changes to 3.8 atm and the temperature increases to 203°C, find the new volume. • Use the combined gas law: P1V1 = P2V2 T1 T2 • P1 = 1.00 atm • V1 = 28.0 cm3 • T1 = 0°C + 273 = 273 K • P2 = 3.8 atm • T2 = 203°C + 273 = 476 K V2 = 12.8 cm3

5. Sec. 12.2 quiz“The Gas Laws” • You may use your book, notes, and a calculator to complete the quiz on your own. • Question #5 was NOT covered in this section…the answer is (C) Dalton. Good Luck!

6. Lab: “Charles’ Law: The Effect of Temperature on Volume”Background • According to the kinetic-molecular theory, an increase in temperature will cause the molecules of a gas to move faster and exert more pressure, causing the gas to expand. • Conversely, as a gas cools, the molecules move more slowly and the gas will contract, or exert less pressure. • The relationship between the volume of a gas and its temperature is known as Charles’s Law.

7. Lab: “Charles’ Law: The Effect of Temperature on Volume”Title, Purpose and Hypothesis • You will have to read through the lab to find the purpose of this lab and write your hypothesis statement.

8. Lab: “Charles’ Law: The Effect of Temperature on Volume”Changes to Materials List • Remember, 1 cm3 = 1 mL • You will use a hot plate NOT a bunsen burner. • Change “thermometer” to “temperature probe”. • You will need a 100 mL graduated cylinder, NOT a 50 mL. • Cross out the barometer – we don’t have one. I will look online to find the atmospheric pressure.

9. Lab: “Charles’ Law: The Effect of Temperature on Volume”Procedure • The procedure for this lab is pretty straight-forward and we will follow the directions in the lab handout. • I have graph paper for you to use to graph your data.

10. Lab: “Charles’ Law: The Effect of Temperature on Volume”Lab Write-up and Reflection Statement • With a partner of your choice, complete the lab write-up. • Don’t forget to leave space for the reflection statement. • Be sure to update your table of contents in your lab folder. We will be in the lab next time: dress appropriately!

11. Gas Laws & Drinking Straws Activity

12. Pre Lab Question(Answer on the back of your post-lab question sheet) Why can we drink through a straw? try to explain it without using the word suck in your description

13. Activity #1 • Fill your cup ½ full of water. • Put your straw in the cup. • Place one finger over the straw and lift it out of the water. • Observe the water in the straw carefully.

14. Activity #2 • Grab a second straw. • Put both straws into your mouth. • Lower one of them into the glass and the other should be outside of the glass. • Try to drink the water through the straw in the glass

15. Activity #3 • Tape two straws together end to end and drink from them. • Continue to add straws until you have a total of 8 straws taped together. • Try drinking out of your elongated straw vertically and as horizontally as possible.

16. Activity #4 (demonstration) • Use flexible tubing to make a giant straw on the stairwell.

17. Post Lab Questions • Why does the water stay in the straw in activity #1? • Why can’t you drink very well in activity #2 (two straws in your mouth)? • Why is there a limit to the height of a straw you can drink from? • What is the maximum theoretical height through which you can drink? Atmospheric pressure = 760 mmHg Mercury is 13.7 times more dense than water is.