4. Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Homework questions/collect (Pg. 432: #1-12)  2 nd combined gas law example and ”Rock Me Avogadro” video for review before quiz  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!

5. Homework Questions Pg. 432: #1-12 Questions/Problems? Hand In

6. Additional Example A gas at STP occupies 28 cm 3 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: P 1 V 1 = P 2 V 2 T 1 T 2  P 1 = 1.00 atm  V 1 = 28.0 cm 3  T 1 = 0°C + 273 = 273 K  P 2 = 3.8 atm  T 2 = 203°C + 273 = 476 K V 2 = 12.8 cm 3

7. 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!

8. 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.

9. 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.

10. Lab: “Charles’ Law: The Effect of Temperature on Volume” Changes to Materials List  Remember, 1 cm 3 = 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.

11. 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.

12. 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!

13. Gas Laws & Drinking Straws Activity

14. 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

15. 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.

16. 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

17. 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.

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

19. Post Lab Questions 1.Why does the water stay in the straw in activity #1? 2.Why can’t you drink very well in activity #2 (two straws in your mouth)? 3.Why is there a limit to the height of a straw you can drink from? 4.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.