changes of state

Thermal energy

The total kinetic and potential energy of all the particles in an object or substance

Temperature

A measure of the average kinetic energy of the particles in an object or substance

Kinetic energy

Energy of motion

Potential energy

Energy that is stored

Thermal energy and temperature are related, but they are not the same thing. How can you understand the difference?

In terms of particles

When you apply heat, what are you transferring?

You are transferring energy from the heat source to the substance

All particles of matter are constantly what

Moving

If you heat a substance, what do the particles do?

It moves faster

What a substance is called and its thermal energy decreases. What do the particles do?

It slows down

Melting

The change in state from a solid to a liquid

Melting point

In pure crystalline solids melting occurs at a specific temperature

At a solid melting point what do the particles do and what happens

It’s particles vibrate so fast that they break free from their fixed positions

Freezing

A change of state from liquid to solid

No matter how much of a substance there is

It will always have the same freezing point and boiling point and melting point

Vaporization

The change in state from a liquid to a gas

When does vaporization occur?

When the particles in a liquid gain enough energy to move independently and away from each other

What are the two main types of vaporization?

Boiling

Vaporization that takes place both below and at the surface of a liquid

Evaporation

Vaporization that takes place only on the surface of a liquid

Although boiling occurs only at one temperature evaporation can…

Occur at all times

What does pressure depend on?

The force you apply in the area over, which you apply the force

Pressure formula

Pressure=force/area

Atmospheric pressure

The air that surrounds you is constantly applying pressure to you

What can atmospheric pressure affect?

How easily a liquid changes to a gas

Atmospheric pressure example

When you boil water to make pasta, atmospheric pressure is acting on the surface of the liquid water as the water is heated on the stove the pressure inside of the liquid increases when the pressure inside of the liquid equals the atmospheric pressure the liquid boils

How can altitude affect the boiling point?

In high altitude, it takes less thermal energy to get a liquid to boil because the atmospheric pressure is less because the air is less dense

Condensation

The change in state from the gas to liquid

When does condensation occur?

When particles in a gas lose enough thermal energy to change state

Sublimation

The change in state from most solid to a gas

When does sublimation occur?

When the surface particles of a solid gain of energy that they formed the gas

What happens during sublimation?

Particles of a solar do not pass through the liquid state as a form of gas I ordinary atmosphere pressures, such as carbon dioxide cannot exist as a liquid so instead of melting, solid carbon dioxide changes directly into a gas as shown in dry ice