Two types of matter:  Mixtures  Pure substances

Mixtures:  Consists of two or more substances that are mixed together but not chemically combined  Ex: pre-baked cookies  Solution – liquid mixture  Soda; sea water  2 types of mixtures  Homogeneous – uniform composition  Heterogeneous – not uniform composition

Pure Substances  Is made of only one kind of matter and has definite properties.  Ex: sugar, salt, gold, iron  Elements – are pure substances that cannot be broken down anymore.  Look at periodic table  Compounds – is a pure substance formed from chemically combining two or more different elements  H2O, CO2, C6H12O6  Atoms – smallest particle of a element

States of Matter Notes  A sheet of paper is about 10,000 atoms thick.  There are 2000 billion billion atoms of oxygen in one drop of water (double that for hydrogen)!  A sheet of paper is about 10,000 atoms thick.  There are 2000 billion billion atoms of oxygen in one drop of water (double that for hydrogen)!

 Atoms are held together by a chemical bond.  A molecule is a group of atoms that are joined together and act as a single unit. For example, H 2 O is made up of 2 hydrogen atoms and 1 oxygen atom and is VERY different from hydrogen alone or oxygen alone.  There are 3 atoms in one molecule of water.

Pure Substances

4 states of matter:  Solids  Liquids  Gasses

4th State of Matter is Plasma. Just be aware of it…

Solids:  have a definite volume and a definite shape.  will keep that volume and shape in any position and in any container.  Particles in a solid are packed very tightly together and stay in fixed positions. These particles do move back and forth slightly—like balls connected by tight springs.

Crystalline solids-- particles form regular, repeating patterns. e.g. salt, sugar, sand. Amorphous solids—no pattern to particles. e.g. Butter, glass, plastic, rubber.

Liquids:  have no shape of their own, but do have a definite volume.  takes shape of container.  Particles in a liquid are packed tightly together but they move around each other freely.

Viscosity: - the resistance of a liquid to flowing. More viscous = more “thick”.

Gases:  have no definite shape or volume.  can change volume easily.  Particles in a gas fly at high speeds in all directions, filling all the space available to them. They can be spread out to “fill” any space or they can compact together in a smaller space.

Draw this

Characteristics Properties  Properties for a given substance that never change. (always remain the same)  water freezes at 32 degrees boils at 212  Physical Changes – alter the form of a substance  Boiling Point  Melting point  Chemical Changes – one or more substances combine or break apart to form new substance  Wood being burnt. Burning in general