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KS3 Chemistry

7G Solids, Liquids and

Gases

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Video: Matter Matter Everywhere

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I. Theories: Elements

A. Thales [580-570 BC]1. Philosopher2. Everything is made up of water3. Water can be liquid, solid, or gas

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B. Empedocles1. Everything was made up of

four substances: Fire, Air, Water and Earth

2. Substances changed because there were two forces that

could affect them: Love and StrifeC. Aristotle

1. Philosopher2. Believed Empedocles idea 3. This was the accepted theory

for 2000 years

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II. Theories: Atoms

A. Anaxagoras1. Philosopher2. Believed that everything was made from tiny ‘seeds’

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B. Democritus2. Actually developed idea of ATOMS3. Different types of materials were made from atoms

a. solids = atoms stuck together

b. liquids and gases = atoms not stuck

together4. Idea was unpopular for 2000 years

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C. John Dalton1. Atomic Theory of Matter2. Many elemental substances

or elements, that make up different types of atoms

3. Elements are composed of extremely small atoms4. Group of atoms = molecule

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Video: History of Atoms

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III. What is Matter

A. Anything that has mass B. Anything that takes up space

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Video: What is Matter?

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IV. Particle Model or Particle Theory of Matter A. All matter is made up of tiny particles B. Particles are always moving =

Kinetic Energy1. The higher the temperature the faster these particles move 2. Heating particles causes them to

move further apart - substance will expand

3. density of a substance Decreases C. The difference between: Solids, Liquids and Gas can be explained by this model

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V. States of MatterA. At room temperature most

substances exist in one of three physical states.1. Solid

a. Keeps its shapeb. has a fixed volumec. has a definite shape

even when movedd. very dense

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e. Particles are vibrating f. Particles held together by strong force of attraction g. Particles cannot move around each otherh. Particles are close together

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2. Liquida. Takes the shape of its containerb. Has fixed volumec. Does NOT have a definite shaped. flows easilye. can’t be compressed into

smaller Volume

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f. Particles are free to move past each otherg. Particles are held together by the force of attraction

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3. Gasa. Has NO definite volumeb. Has NO definite shapec. Fills all available spacesd. flows easily e. Not densef. almost NO force of attraction between particlesg. particles move very fast

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Three States of Matter

solid liquid gas

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How do smells spread out?

Where is the smell coming from and how does it spread out?

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VI. Diffusion A. What is Diffusion

1. Diffusion is the movement of particles that allows them to

spread out from high concentration to low concentration and mix with other

particles

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B. Occurs in liquids and gases, but NOT solidsC. Occurs more quickly In gases than liquidsD. Occurs more quickly in warmer temperatures than cooler temperatures

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Video: Diffusion