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Particle Theory of Matter (pp. 136-143)

Matter: anything that has mass, takes up space, and is made of particles.

Matter is made of tiny particles which combine to make larger particles, and eventually complex objects

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1. all matter is made of tiny particles

2. these particles are always moving; they move faster with more energy

3. there are spaces between particles

4. there are attractive forces between particles

5. the particles of one substance differ from particles of other substances

Kinetic energy: energy that particles or an object has due to its motion.

Kinetic energy of objects or particles depends on two things:

Mass of the object

Speed at which object is moving

If two objects have the same mass, the one moving faster has more kinetic energy

If two objects are moving at the same speed, the one with more mass has more kinetic energy

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Temperature: a relative measure of how hot or how cold something is; the average kinetic energy of the particles of a substance

In an object with a higher temperature, the particles are moving faster and have more energy. In contrast, in lower temperature objects particles are moving slower. Note: not all particles in an object have the same amount of energy.

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States of Matter (pp. 144-157)

There are 3 basic states of matter Solid

Liquid

Gas

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Has a fixed shape (does not change to fit its container)

Definite volume (as long as temperature is constant)

Particles packed closer together; strong forces; particles vibrate

No definite shape; takes shape of container it's in

Definite volume (as long as temperature stays the same)

Particles are not as close together; forces between particles weaker; particles can move around more

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No definite shape and no definite volume

Particles are extremely far apart; forces between particles are extremely weak; particles are always moving

Thermal expansion: the volume of an object increases when the temperature increases

Thermal contraction: the volume of an object decreases when the temperature decreases

Temperature increases gives the particles of a substance more energy, allowing them to move faster and further apart. This causes the volume to increase. Temperature decreases do the opposite.

Volume changes more obvious in gases, compared to liquids and solids because the forces are weaker

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Changes of State (pp. 158-171)

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Change of state: the change from any of the three states (solids, liquids, and gases) to any other state

6 basic changes of state: Melting

Freezing

Evaporation

Condensation

Sublimation

Deposition

Melting: solid changing to a liquid

Freezing: liquid changing to a solid

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Evaporation: liquid changing to a gas

Condensation: gas changing to a liquid

Sublimation: change from a solid to a gas

Deposition: change from a gas to a solid

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As a substance is heated, its particles gain energy and move faster and attempt to move further away from each other. The forces that are present between them are not strong enough to hold them in place

ex. melting, evaporation, sublimation

As a substance is cooled, its particles lose energy and move slower. Attractive forces between the particles can now hold the particles closer together.

ex. freezing, condensation, deposition

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Melting point: the temperature at which a solid state to become a liquid

Boiling point: the temperature at which a liquid becomes a gas

The melting point and freezing point of a substance are the same temperature.

Different substances have different melting and boiling points due to different attractive forces.

Heating curve: a graph that demonstrates the changing of states of a substance by plotting temperatures versus time, when energy is continuously added to a substance

Heating curves have plateaus (flat areas) where changes of state occur as the heat energy absorbed by the substance is used to overcome attractive forces, not to make the particles move faster.

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