Transcript Lab Write-up and Reflection Statement

Friday, Jan. 18th: “A” Day
Tuesday, Jan. 22nd: “B” Day
Agenda
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!
Homework Questions
Pg. 432: #1-12
Questions/Problems?
Hand In
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
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!
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.
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.
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.
Lab: “Charles’ Law: The Effect of
Temperature on Volume”
Procedure
The procedure for this lab is pretty straightforward and we will follow the directions in
the lab handout.
I have graph paper for you to use to graph
your data.
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!
Gas Laws & Drinking Straws
Activity
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
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.
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
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.
Activity #4 (demonstration)
Use flexible tubing to make a giant
straw on the stairwell.
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.