Classification of Matter

A.  Composition of Matter

1.  Matter is anything that has mass and takes up space (has volume)

2.  All matter is made of particles

3.  Pure substances are made of the same kind of particles

a.  Elements

1)  Made of atoms

2)  109 elements

b.  Compounds

1)  Particles are made of combinations of atoms in a definite ratio

2)  Millions

4.  Mixtures are made of different kinds of particles

a.  Heterogeneous mixtures have particles that are easily distinguished

1)  Colloids

a)  Particles never settle out

b)  Particles scatter light and are easily distinguished (Tyndall effect)

2)  Suspensions contain particles that settle out

b.  Homogeneous mixtures have particles that are uniformly spread out (also called solutions)

B.  Properties of Matter

1.  Physical properties are characteristics that can be observed without changing the substances that make up the material

a.  Examples of physical properties:

1)  Changes of state

2)  Color

3)  Odor

4)  Hardness

5)  Density

6)  Ability to conduct heat

7)  Ability to conduct electricity

8)  Attraction to magnets

b.  Physical changes

1)  Do not change the identities of the substances in a material

2)  Examples:

a)  Change in size or shape (breakage)

b)  Change in state (melting, freezing, vaporization, condensation, sublimation)

2.  Chemical properties are characteristics that indicate if a material can undergo a certain chemical change

a.  Chemical changes are changes of one substance into a different substance

b.  Examples:

1)  Burning

2)  Explosions

3)  Rotting

4)  Rusting

5)  Foaming

c.  Clues for chemical changes

1)  If something can burn

2)  Rapid production of energy (light, sound, etc.)

3)  Production of gas bubbles

4)  Distinct change in odor

5)  Color change (not always reliable)

6)  If something can corrode

C.  The Law of Conservation of Mass

1.  Matter can be neither created nor destroyed during a chemical change

2.  The total mass of all substances must be equal to the total mass after a chemical change

3.  There can be no loss of mass nor gain of mass during a chemical change