Gas

• No definite volume or shape
• Particles are spread apart
• Particles move quickly
• Most energy

kinetic theory

• gas particles: small, hard spheres, no volume
• rapid, constant, random motion
• collisions are elastic

Gas pressure

• gas particles simultaneously colliding with an object.
• vacuum=no particles, no collisions, no pressure
• SI unit Pascal Pa
• 100kPa = 1 atm = 760mmHg

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Liquid

• Definite volume
• No definite shape
• Particles are further apart
• Particles move freely
• More energy

Vapor pressure
force exerted by gas on a liquid.
Equilibrium when rate of evapration=rate of condensation.

Solid

• Definite shape and volume
• Particles close together
• Particles slightly vibrate
• Least amount of energy

Adding or removing energy changes states of matter.

Thermal energy is responsible for phase changes.

Thermal energy is the energy that comes from heat. This heat is generated by the movement of tiny particles within an object. The faster these particles move, the more heat is generated.

Temperature is a measure of the average heat or thermal energy of the molecules in a substance.

Easy way to think of the difference between thermal energy(heat) and temperature:
A swimming pool and a cup of water can have the same temperature but the pool will have much higher thermal energy (heat).

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