Boyle's Law

1. MELC #21:
Investigate the relationship between:
-volume and pressure at a constant
temperature of a gas

2. Learning Objectives:
1 2 3
Identify the
properties of
gas and their
relationship to
each other.
Solve
problems
using Boyle’s
Law.
Demonstrate
how Boyle’s
Law affects
our daily
living.

3. Picture Analysis
Describe the
molecules
based on its
movement,
spaces,
number.

4. Graph Me!
Study the figures on the next
slide. Plot the volume and
pressure on each of the
graphs. Connect the plotted
points and interpret the
relationship of the variables.

5. Graph Me!

6. INTERPRETATION

7. Behavior of
Gases:
Boyle’s law and
its Application

8. Gas - a fluid (such
as air) that has
neither independent
shape nor volume
but tends to expand
indefinitely.

9. General Properties of Gas:

10. General Properties of Gas:
1. Gas has no definite shape and
volume. Their volume is the
volume of their container.

11. General Properties of Gas:
2. They are compressible when
pressure is exerted and they also
exert pressure.

12. General Properties of Gas:
3. Gases expand when heated and
contract when cooled.

13. General Properties of Gas:
4. The intermolecular force of
attraction between their particles is
negligible, thus, they diffuse easily.

14. Measurable Properties of Gas:
VOLUME
PRESSURE
TEMPERATURE

15. Measurable Properties of Gas:
VOLUME
The volume of a gas
is equal to the
volume of its
container.

16. Measurable Properties of Gas:
VOLUME
The common units of volume
used in gas
measurements are liter (L),
milliliter (mL), cubic meter (m3)
and cubic centimeter (cm3).

17. Measurable Properties of Gas:
PRESSURE
The pressure of a gas is the
force exerted by the gas
molecules on the walls of its
container divided by the
surface area of the container.

18. Measurable Properties of Gas:
PRESSURE
The Earth’s atmosphere
exerts pressure =
1.013 x105 N/m2 or 1 atm
(atmosphere).

19. Measurable Properties of Gas:
PRESSURE
Common Units of Pressure:
1 atm = 1.013 x10^5 N/m2 = 1.013 x10^5 Pa
1 atm = 760 torr = 760 mmHg
1 atm = 14.696 psi.

20. Measurable Properties of Gas:
TEMPERATURE
The temperature of a gas
is the average kinetic
energy of the particles of
gas.

21. Measurable Properties of Gas:
TEMPERATURE
It is usually expressed in
degree Celsius (°C),
degree Fahrenheit (°F)
and Kelvin (K).

22. Measurable Properties of Gas:
TEMPERATURE
°C = (°F -32) / 1.8
°F = 1.8°C + 32
K = °C + 273
Measurable Properties of Gas:

23. Standard Conditions of Gas:
1. The standard temperature is
the melting of an ice which is 0°C or
273K.
2. The standard pressure is the average
pressure of the atmosphere at sea level
which is equal to 1 atm. One mole of gas
occupies a volume of 22.4 L.

24. Picture Analysis

25. Picture Analysis
What happens to the
balloon when the plunger
of the syringe is being
pushed? How about if
being pulled?

26. Boyle’s law is a gas
law which states that the
pressure exerted by a gas (of a
given mass, kept at a constant
temperature) is inversely
proportional to the volume
occupied by it.

27. Boyle’s law
was put forward by the Anglo-
Irish chemist Robert Boyle in
the year 1662.

28. Boyle’s law

29. Boyle’s law

30. Sample Problem:
1. Two liters of gas is confined in a
container under a pressure of 760 mmHg.
What could be the new volume if the
pressure is increased to 1,520 mmHg.

31. Sample Problem:
Given: V1 = 2 L
P1 = 760 mmHg
P2 = 1,520 mmHg
Required: Final Volume (V2)
Equation: V1P1=V2P2

32. Sample Problem:
Solution:
(2L) (760 mmHg) = (V2) (1520 mmHg)
V2 = (2L) (760 mmHg)
1520 mmHg
Answer: V2 = 1L

33. Try this!
An argon gas occupies 56.2 L at 760
torr. If the volume of gas is decreased
to 1⁄4 of the original volume, calculate
its final pressure.

34. Try this!
At 0°C and 5 atm, a given sample of
gas occupies 75 L. The gas is
compressed to a final volume of 30 L
at 0°C. What is the final pressure?

35. Answer
Given:

36. Answer
Required: P2

37. Answer
Equation: P V = P V2
1 1 2

38. Answer
Solution:

39. Answer
Answer: 3040 torr

40. Try this!
At 0°C and 5 atm, a given sample of
gas occupies 75 L. The gas is
compressed to a final volume of 30 L
at 0°C. What is the final pressure?

41. Answer
Given:

42. Answer
Required: P2

43. Answer
Equation: P V = P V2
1 1 2

44. Answer
Solution:

45. Answer
Answer: 12.5 atm

46. MELC: (Day 3)
Investigate the relationship between:
-volume and pressure at a constant
temperature of a gas

47. Learning Objectives:
1 2 3
Identify the
properties of
gas and their
relationship to
each other.
Solve
problems
using Boyle’s
Law.
Demonstrate
how Boyle’s
Law affects
our daily
living.

48. Performance
Task 1:
Boyle’s Law
Model

49. Objective:
Create your own model for
Boyle’s Law.

50. Materials:
2 pcs. balloon
1 plastic bottle (mismo bottle)
Scissors
Tape

51. Procedure:
1. Cut off the bottom portion of the bottle.
2. Take one balloon. Cut off its narrow end or its
opening. The part left should look like a shower
cap.
3. Stretch this part of the balloon to cover the
bottom part of your bottle. This will serve as the
membrane.

52. Procedure:
4. Take the other balloon. Fold the opening of this
balloon around the rim of the bottle to hang it
upside down.
5. Now that your model is ready, slightly pull the
balloon membrane of the bottle and observe what
happens to the balloon hanging in the rim.
6. Let go of the membrane and observe again.