Page 154 - text book form physics kssm 2020

4.4 Gas Laws

Pressure, Temperature and Volume of Gas
Photograph 4.3 shows an air cushion wrap used in packaging of goods.
When it is compressed, the air inside gives resistance. Th is observation
can be explained in terms of the behaviour of gas molecules based on
the Kinetic Th eory of Gas.

Photograph 4.3 Air cushion
wrap being compressed

Activity 4.9 ISS ICS

Aim: To observe the behaviour of gas molecules through computer simulation
Instructions:
1. Carry out a Think-Pair-Share activity.
2. Scan the QR code to see the simulation on the behaviour of gas molecules. Based on
the simulation, discuss:
(a) movement of gas molecules
(b) space fi lled by gas molecules Simulation of behaviour of
(c) direction of motion of molecules gas molecules
(d) collisions between gas molecules and the walls of
the container
(e) effects of increasing and decreasing of pressure,
temperature and volume of gas on the behaviour of
the gas molecules http://bt.sasbadi.com/p4148
3. Present your fi ndings.

Table 4.8 explains pressure, temperature and volume of gas in a closed container based on
the Kinetic Th eory of Gas.

Table 4.8 Pressure, temperature and volume of gas based on the Kinetic Th eory of Gas
Characteristic of gas Description

Pressure • Gas molecules always move randomly.
• When gas molecules collide with the wall of the container and rebound, a
force is exerted on the wall of the container.
• Force per unit area is the pressure of the gas.

Temperature • Average kinetic energy of gas molecules increases with temperature.

Volume • Gas molecules move freely and fi ll the entire space of the container.
• Volume of gas is the same as the volume of its container.

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148 4.4.1
4.4.1