Y8 Chemistry

Practice for Mid Topic test

What are atoms?

The tiny particles that make up matter, they are the building blocks of matter.

What is a molecule?

A group of two or more atoms chemically bonded together.

What is a compound?

A substance made up of more than one type of atom chemically combined.

What is matter?

Anything that takes up space and has mass.

What is a solid?

A state of matter where the particles are packed closely together in a highly organised matter.

What is a liquid?

A state of matter where the particles are still quite close together but not as tightly packed together as solids.

What is a gas?

A state of matter where the particles are very far apart and can move about freely.

What does diffusion mean?

The movement of molecules from a region of high concentration to a region of low concentration.

What does melting mean?

The process by which a substance in the solid state changes to the liquid state.

What does solidification/freezing mean?

The process by which a substance in the liquid state changes to the solid state.

What does condensation mean?

The process by which a substance in the gaseous state changes to a liquid which occurs by cooling down gas.

What does sublimation mean?

The process by which a substance in the solid state changes directly into a gaseous state, skipping the liquid state.

What does melting point mean?

The temperature at which a substance changes from a solid to a liquid.

What does boiling point mean?

The temperature at which a substance changes from a liquid to gas.

What are the properties of a solid?

1. Particles vibrate in place

2. Fixed volume and shape

3. Can’t be compressed

4. Particles can’t flow.

What are the properties of a liquid?

1. Fixed volume

2. Takes the shape of the bottom of the container

3. Can’t be compressed

4. Particles slowly flow.

What are the properties of a gas?

1. No fixed volume or shape

2. Fill any container they are held in

3. Can be compressed

4. Particles can rapidly flow

What is matter made of?

Very small particles that are constantly moving.

What energy do the particles in matter have?

Kinetic energy.

Why can’t solids and liquids be compressed?

Their particles are already very closely packed together.

Why can gases be compressed?

Their particles have a lot of empty space between them.

List the states from lowest to highest particle kinetic energy.

Solids, liquids, gases.

Why do solids have a fixed shape and volume?

Their particles only vibrate in place. ( Vibration is a small movement )

Why do liquids carry more kinetic energy than solids?

Whilst the particles in a liquid can flow over the top of each other, the particles in solids, can barely move at all, only vibrating in place. More movement means more kinetic energy.

Why do gases have much more kinetic energy than solids and liquids?

In gas the particles move around freely in all different directions, whereas the movement of particles in solids and liquids are much more restricted. Kinetic energy is the energy of motion, so the more movement the higher kinetic energy.

What happens to particles if you increase temperature?

Particles will have increased kinetic energy.

What happened to particles if you decrease temperature?

Particles will have decreased kinetic energy.

Do particles with strong bonds have a high or low energy state?

A low energy state.

Do particles with weak bonds have a high or low energy state?

A high energy state.