do now (5 min)
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Do Now (5 min). 1. What happens to the pressure of a gas when you raise the temperature? 2. What happens to the pressure of a gas when you INCREASE the volume?. Do Now Discussion. What happens to the pressure of a gas when you raise the temperature? - PowerPoint PPT PresentationTRANSCRIPT
Do Now (5 min)1. What happens to the pressure of a gas when
you raise the temperature?
2. What happens to the pressure of a gas when you INCREASE the volume?
Do Now DiscussionWhat happens to the pressure of a gas when
you raise the temperature?
What happens to the pressure of a gas when you INCREASE the volume?
Pressure INCREASES
Pressure DECREASES
Do Now – 4/23/101. What happens to pressure as volume
increases?2. What happens to volume as pressure
increases?3. What happens to Mr. Sandine as your grade
decreases?
Setup Cornell Notes – “Gas Laws”
The Gas Laws4-18-10
Cornell NotesWorksheet Relay
AgendaDo NowCornell Notes (3 gas laws)Worksheet Relay
Remember…Gases have four different properties we can
measure in numbers:According to Kinetic Molecular Theory, gases
have these properties because they are made of moving particles.
Why are we learning about gases?Gases affect our lives in many ways
We need it to survive (oxygen)Air pressure is responsible for our ears and
lungs to function
To predict these behaviors, we need to be able to use the three gas laws that gases obey.
Boyle’s LawP α 1/V
Pressure and volume are INVERSELY proportional if moles and temperature remain constant
When P goes up, V goes down and vice versa
P1V1 = P2V2
Robert Boyle (1627-1691). Son of Earl of Cork, Ireland.
Example 1:If the pressure of a gas starts at 2 atm and it’s
volume is 5.0 L, what happens to the pressure when the volume increases to 15.0 L?
P1V1 = P2V2
Before
After
(2 atm)
(5.0 L)
= (x atm)
(15.0 L)
(15.0 L)
(15.0 L)
If we change the volume, the pressure changes to 0.67 atm
Example 2:If the pressure of a gas starts at 5 atm and it’s
volume is 10.0 L, what happens to the pressure when the volume decreases to 5.0 L?
P1V1 = P2V2
Before
After
(5 atm)
(10.0 L)
= (x atm)
(5.0 L)
(5.0 L)
(5.0 L)
If we change the volume, the pressure changes to 10.0 atm
Boyle’s LawBoyle’s LawA bicycle pump is a
good example of Boyle’s law.
As the volume of the air trapped in the pump is reduced, its pressure goes up, and air is forced into the tire.
Charles’s LawV α T
Volume and temperature are DIRECTLY proportional IF moles and pressure remain constant
When V goes up, T goes up
V1 = V2
T1 T2
Jacques Charles (1746-1823). Isolated boron and studied gases. Balloonist.
Example 1:If the volume of a gas is 4.0 L and it’s
temperature is 50 K, what happens to the volume if the temperature changes to 75 K?
V1 = V2
T1 T2
Before
After
4.0 L
50 K=
X L
75 K
If we change the temperature, the volume changes to 6.0 L
Example 2:If the volume of a gas is 8.0 L and it’s
temperature is 200 K, what happens to the volume if the temperature changes to 100 K?
V1 = V2
T1 T2
Before
After
8.0 L
200 K=
X L
100 K
If we change the temperature, the volume changes to 4.0 L
Charles’s BalloonHeat up the air (raise the
tempreature), the volume increases (balloon inflates)
Gay-Lussac’s LawP α T
Pressure and temperature are DIRECTLY proportional IF moles and volume remain constant
When P goes up, T goes up
P1 = P2
T1 T2
Joseph Louis Gay-Lussac (1778-1850)
Example 1If the pressure of a gas is 5.0 atm and the
temperature is 50 K, what will the temperature be if the pressure decreases to 3.0 atm?
P1 = P2
T1 T2
Before
After
5.0 atm50 K
=3.0 atmX K
If we change the pressure, the temperature drops to 30 K
Example 2If the pressure of a gas is 5.0 atm and the
temperature is 50 K, what will the temperature be if the pressure increases to 10.0 atm?
P1 = P2
T1 T2
Before
After
5.0 atm50 K
=10.0 atmX K
If we change the pressure, the temperature drops to 100 K
Combined Gas LawGood news! We don’t have to memorize all
three laws! Since they’re all related, we can combine them into ONE equation!
• If you only need one of the other gas laws, you can cover up the item that is constant and you will get that gas law!
= P1 V1
T1
P2 V2
T2
Boyle’s Law
Charles’ Law
Gay-Lussac’s Law
PracticeComplete the worksheet problems on a
SEPARATE sheet of paperHave Mr. Sandine check your work after each
round BEFORE you move on to the next round!
Next Monday, we will be in the computer lab (342)
Trifolds are due todayIf you have any other HW (Study guides,
vocab, 13.1, etc, make sure you get it checked in)