1. Boyle’s Law

2. Objective
 At the end of this lesson you should be
able to:
 Determine the relationship between
pressure and volume
 Solve problems involving pressure and
volume

3. Introduction
 Feel your chest
 Breath slowly
 What happen to your chest??
 Why its expend??

4. Relationship between pressure
and volume
 When the volume is decrease, molecules will
have smaller space to move
 Molecules collide more often with the wall and
with another molecules
 So the rate of collision increase therefore the
pressure are increases too
 Some simulation>>..
 Some simulation>>’’

5. Boyle’s Law
 Boyle’s Law state for constant mass and
temperature,
 “Pressure are inversely proportional to its
volume”

6. Boyle’s Law
 In mathematical equation:
 PV = constant
 So we can conclude:
P1V1=P2V2

7. Lets do the graph!!
 P inversely to V  P directly proportional to
1
_
V
P P
0 0 1
_
V
V

8. Graph!!
 Because PV is a constant value we can
get this graph:
PV PV
0 P 0 V

9. Example

10. Explanation
V2= 120 L
P2= ? atm
V1= 30 L
P1= 1 atm

11. Solution

12. Example

13. Explanation
Before Push After Push
P1 250 mm P2 200 mm
750 mm 746 mm
P1=(Atmospheric Pressure – 750) mm Hg
P2=(Atmospheric Pressure – 746) mm Hg

14. Solution
Atmospheric Pressure of mercury is 766mm Hg
Atmospheric Pressure of water is 10 m Water

15. What if??
750 mm
250 mm P1
Up side down
P1=(Atmospheric Pressure + 750) mm Hg