Pure Substances and Mixtures

Scientists use models when they want to describe things that are difficult to understand.

• True

• False

The particle model theory describes important aspects of matter:

• There are forces between the particles.

• All matter is made up of millions of particles that are incredibly small

• The spaces between the particles in matter are empty.

• The particles in matter are always moving. The more energy they have, the faster they move.

• All of the Above

Brownian Motion:

“The random movement displayed by small particles that are suspended in fluids (liquids and gases)”

• True

• False

The random movement of liquid or gas particles from a high concentration to a low concentration to spread evenly is known as

The kinetic theory of matter states that matter is made of tiny particles (i.e. atoms and molecules) and that they are always in constant motion.

• True

• False

Packed in a regular arrangement with very small spaces between the particles. High density

• Solid

• Liquid

• Gas

Particles are held together by relatively strong forces of attraction. So they move freely, yet still stay together

• Solid

• Liquid

• Gas

Have no fixed shape because particles move around rapidly with a lot of energy. It fills up the space it is in.

• Solid

• Liquid

• Gas

Can diffuse as the particles move freely

• Solid

• Liquid

• Gas

Particles vibrate in a fixed position with low energy

• Solid

• Liquid

• Gas