Ch. 7.2 Fluids and the Particle Theory of Matter

Matter matter – anything that has mass and volume mass – amount of matter in an object volume – measure of how much space a substance takes up

The Particle Theory of Matter particle theory of matter – theory that states: that all matter is made up of particles; that all particles of one substance are identical; that particles of matter are in constant motion; that temperature affects the speed at which particles move; that particles have forces of attraction between them; and that there are spaces between particles

The Particle Theory of Matter 1. All matter is made up of particles.

The Particle Theory of Matter 2. All the particles of one substance are identical.

The Particle Theory of Matter 3. Particles of matter are in constant motion.

The Particle Theory of Matter 4. Temperature affects the speed at which particles move. COLD = SLOW WARM = FAST

The Particle Theory of Matter 5. Particles have forces of attraction between them.

The Particle Theory of Matter 6. There are spaces between particles.

GAS SOLID LIQUID

How the Particle Theory Explains Properties of Fluids particle theory states that particles are attracted to each other in some substances, however, particles may be more attracted to particles in other substances example: salt (sodium chloride) dissolving in water

Liquids Can Flow particles in a liquid can overcome some of their attraction to each other and slide past each other this is what allows liquids to flow and take the shape of their container

Gases Can Flow gas particles move so quickly and are so far apart that they overcome almost all their attraction to each other this is why gases flow and spread out to all parts of their container example: air freshener sprayed in one part of a room can soon be smelled in other parts of the room

Thermal Expansion and Contraction thermal expansion – an increase in the volume of a substance in response to an increase in its temperature when the temperature of a solid, liquid, or gas increases, its particles move faster and farther apart thermal contraction – a decrease in the volume of a substance in response to a decrease in its temperature when the temperature of a solid, liquid, or gas decreases, its particles move slower and closer together