Gas Laws and Kinetic Theory
The kinetic molecular theory explains the behaviour of gases in terms of the movement of particles. Gas laws describe the mathematical relationships between pressure, volume, and temperature.
What You Need to Know
Key Concept Diagram
Gas particles move randomly and rapidly, colliding with each other and container walls
Pressure is caused by gas particles colliding with container walls
Increasing temperature increases particle speed and therefore pressure (in a fixed volume)
Boyle's Law: pressure and volume are inversely proportional at constant temperature (P x V = constant)
Key Vocabulary
Kinetic molecular theory
The model that explains gas behaviour through the random motion of particles
Pressure
The force exerted per unit area by gas particles colliding with a surface
Boyle's Law
At constant temperature, the pressure and volume of a gas are inversely proportional
Absolute zero
The lowest possible temperature (0 K = -273 degrees C); all particle motion theoretically stops
Knowledge Check
Select the correct answer for each question. Click "Check Answer" to see if you are right.
Question 1
A sealed syringe has its plunger pushed in, reducing volume by half. What happens to the gas pressure? (temperature constant)
Question 2
Why does a balloon expand when heated?
Question 3
At absolute zero, what happens to gas particle motion according to kinetic theory?
Key Concepts Summary
- ●Gas particles move randomly and rapidly, colliding with each other and container walls
- ●Pressure is caused by gas particles colliding with container walls
- ●Increasing temperature increases particle speed and therefore pressure (in a fixed volume)
- ●Boyle's Law: pressure and volume are inversely proportional at constant temperature (P x V = constant)