KINETIC THEORY OF

MATTER.

What is matter?

• Anything that has mass and takes up space

Matter

Kinetic Theory of Matter…• All matter is made up of particles• Different substances have different

sized particles• Particles are always moving - move

faster at higher temperatures• Particles are held together by bonds that vary in strength

mixture Composed of two or more substances, but each keeps its original properties.

States o MatterSolids Liquids Gases

Space between particles

Very small Very small Large

Bond between particles

Strong (rigid structure)

Strong Very weak

Movement of particles

Vibrate in a fixed position

Roll over each other

Move freely

States of Matter

• Which state(s) have a definite shape?

• Which state(s) have a definite

volume?

• Which state(s) are able to be

compressed?

• Which state(s) can flow?

• Which state(s) have particles which

move?

States of Matter

Classifying Matter

Matter

Pure Substances Mixtures

HomogeneousMixtures

HeterogeneousMixtures

Elements Compounds

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Most atoms are combined with others in nature.

PHASE CHANGECH3CH2OH (l) CH3CH2OH (g)

CHEMICAL CHANGE CH3CH2OH + 3 O2 2 CO2 + 3 H2O

Pure Substances and Mixtures

Pure substances are either:Elements OR Compounds

-cereal with milk- salad- trail mix- sand- cement

- milk- steel (iron and carbon)- fog

Pure water - H2O molecules.Salt - NaCl molecules.A ruby stone - Al2O3 molecules.

Carbon (in the tip of your pencil)Gold is made only of atoms of Gold.

Mixtures are: Homogenous OR Heterogeneous

(the same throughout) (vary throughout)

Classifying Matter

Pure Substances

Elements Compounds

…can be broken down into atoms

Examples: Carbon (in the tip of your pencil) is made solely of carbon atoms.

Gold is made only of atoms of Gold.

…can be broken down into molecules.

Examples: Pure water consists only of H2O molecules.Salt consists only of NaCl molecules.A ruby stone consists of Al2O3 molecules.

Models of Matter

Mixtures

Heterogeneous mixtures- different particles are large enough to be seen or felt.

Homogeneous mixtures -very well mixed-looks and feels like one substance (Solutions are homogeneous mixtures)

Examples:-cereal with milk- salad- trail mix- sand- cement

Examples:- milk- steel (iron and carbon)- fog

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• Consist of only 1 type of atom

O O OO O

OO

O

O OOO

O

Oxygen Atom

Element

Example: oxygen

Elements-

• A group of two or more atoms linked together by a bond

O O

Examples: oxygen water

O

HH

Molecule-

• A group of two or more DIFFERENT atoms linked together by a bond Examples:

water salt

O

HH

Na

Cl

Compound-

•Compounds can be broken down into molecules

OHH

OHH

OHH

OHHO

HHO

HHO

HH

Water is a compound

Single water molecule

PRACTISE

Identify each of the following substances as either an element, compound, solution or mixture:a. Sodium bromide (solid white granules)b. An aqueous mixture of bluestone (copper

sulfate)c. Sulphur (a yellow powder)d. Iodine and alcohol (a brown liquid)e. Sand and sea salt (silicon dioxide and

sodium chloride)f. Waterg. Airh. sugar

Practise

PRACTISE

Each shape below represents an atom of a particular element. a) State whether each is a representation of a group of atoms or a group of molecules.b) State whether the diagram represents an element, a compound, or a mixture.

Practise

Write a definition for the following words:

• Pure substance• Mixture• Atom• Element• Molecule• Compound

• Mixture- Composed of two or more substances, but each keeps its original properties. A mixture can be physically separated into pure compounds or elements

• A pure compound has a constant composition with fixed ratios of elements.

Mixtures

HOMOGENEOUS MIXTURES• The prefixes "homo"-

indicate sameness.• A homogeneous mixture

has the same uniform appearance and composition throughout.

HETEROGENEOUS MIXTURES• A heterogeneous mixture

consists of visibly different substances or phases. The three phases or states of matter are gas, liquid, and solid.

• Substances change state when energy or heat is added to them

• Heat gives the particles more kinetic energy causing them to expand

Changes in states of matter

• Melting Point• Freezing Point• Boiling Point • Condensation Point

Changes in states of matter

                                                            

In a physical change, the substance involved remains the same substance, even though it may change state or form.

In a chemical change, the original substance is changed into one or more different substances that have different properties.

Physical vs. Chemical Changes

Chemical or Physical?

Example: A burning candle

Physical:• solid becomes liquid• liquid becomes solid

Chemical:•Wax vapour becomes carbon dioxide, water and energy

How can we tell that a chemical change had occurred?

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The following are clues that a chemical change has happened:

• Heat or light is given off

• Bubbles of gas are formed

• A new colour appears

• The change is difficult to reverse

• A solid material (called a precipitate) forms in a liquid

More examples

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Chemical ChangePhysical Change

• tarnishing silver

• tearing clothes

• crumpling paper • bleaching your hair

• burning toast

• fireworks exploding

• rusting bicycle

• melting ice cream

• glass breaking

• spoiling food

• boiling water

• sawing wood