BOYLE’S LAW
Gases expand spontaneously to fill any volume available to them. Consequently, the volume of a gas
equals the internal volume of the container in which it is held. The volume of gases unlike those of solids and
liquids is greatly affected by changes in pressure and temperature
Objectives:
1. Relate the volume of a gas to its pressure;
2. Solve problems involving Boyle’s law
I. DISCUSSIONS
 Boyle’s law states that the volume of a fixed quantity of gas maintained at constant temperature is
inversely proportional to the pressure.
𝑷 ∝
𝟏
𝑽
 When two measurements are inversely proportional, one gets smaller as the other gets larger.
 Boyle’s law can be express in mathematical terms:
𝑷𝑽=𝒌
or
𝑷𝟏 𝑽𝟏 = 𝑷𝟐 𝑽𝟐
 The value of the constant depends on the temperature and the amount of gas in the sample.
II. WARMING UP
A. Fill in the blanks. Choose from the given options in the box below.
Boyle’s Law and Breathing Process
Between breaths, the gas pressure inside the lungs equals the atmospheric pressure. The volume of the
lungs is governed by the 1) _______________, which can expand and contract, and the 2) _______________,
a muscle beneath the lungs. 3) _______________ occurs when the rib cage expands and the diaphragm moves
downward. Both of these actions serve to 4) _______________ the volume of the lungs, thus decreasing the
gas pressure inside the lungs. The atmospheric pressure then forces air in the lungs until the pressure in the
lungs once again 5) _______________ atmospheric pressure. 6) _______________ involves the reverses of
the process. The rib cage contracts and the diaphragm moves up, both of which 7) _______________ the volume
of the lungs. Air is forces out of the lungs by the increase in 8) _______________ caused by this reduction in
volume.
Decrease
Diaphragm
Equals
Exhalation
Increase
Inhalation
Pressure
Rib Cage
B. Answer the following questions.
1. Gas cylinders, LPG tanks and oxygen tanks are made of very strong materials like steel. Why are plastic,
glass, and ordinary tin cans not used as gas storage?
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
2. What basic assumption of the Kinetic Molecular Theory (KMT) explains Boyle’s Law?
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
III. WORKING OUT
Answer the following and show your complete solution by following GUSAO.
1. What volume will 50 mL of a gas at 725 Torrs occupy if the pressure is increased to 760 Torrs?
2. A gas occupies 250 mL when the barometer reads 720 mm. How many milliliters will it occupy when the
barometer reads 740 mm?
3. Find the volume of a gas at standard pressure if its volume at 780 mm Hg is 80 mL?
4. If the volume of a gas, at constant temperature, changes from 200 ml to 500 mL, the pressure on the gas
must have changed from 400 torr to ____________.
5. Boyle’s Law describes the relationship between ___________ and _____________, and they are
___________ proportional. The variables __________ and ___________ remain constant.
6. A balloon is filled with 73 L of air at 1.3 atm pressure. What pressure is needed to change the volume to 43
L?
7. If 50 mL of Oxygen gas is compressed from 20 atm of pressure to 40 atm of pressure, what is the new
volume at constant temperature?
8. If a gas sample in a balloon had a volume of 100 mL and a pressure of 3 atm. It was then compressed to a
pressure of 10 atm, what would be its volume?
9. At 0.75 atm, the volume of a gas is 300 mL. If the temperature remains constant and the pressure is
changed to 456 torr, what is the new volume of the gas?
IV. WRAPPING UP
Create a concept map by using the following words inside the box. Link the words in the box with another
word/phrase to show how these concepts are related to each other.
Boyle’s Law
Gas Volume
Quantity of Gas
Moles
Temperature
Gas Pressure
Collision of Molecules
Container