Materials

There are 3 states of matter: solid; liquid; gas.

• All matter consists of tiny particles called atoms.
• Atoms can only be seen with an electron microscope.

1. Solids

• Do not flow.
• Fixed volume, so they cannot be compressed.
• Fixed shape.

2. Liquids

• Can flow.
• Fixed volume, so they cannot be compressed.
• No fixed shape.

3. Gases

• Can flow.
• No fixed volume, so they can be compressed.
• No fixed shape.

Chemical Bonding

• Atoms in solids are tightly chemically bonded to one another.
• Atoms in liquids are more loosely chemically bonded to one another.
• Atoms in gases are very loosely chemically bonded to one another.
• The bond strength determines the state of matter.
• We can change the state of matter through different processes.

Changing States of Matter

1. Melting: solid—> liquid
2. Evaporation: liquid—> gas
3. Condensation: gas—> liquid

Melting

• Heating a solid makes its particles vibrate more.
• With enough heat, the particles break free and slide past each other, forming a liquid.

Boiling

• As the temperature of a liquid rises, its particles vibrate more and move further apart.
• Each liquid has a specific boiling point, such as water at 100°C and alcohol at 78°C.

Evaporation

• Evaporation happens at the surface of a liquid, turning it into a gas.
• It differs from boiling, which occurs throughout the liquid.

Condensation

• Cooling a gas slows down its particles.
• This process turns the gas into a liquid.