1. Classification of Matter
Ch. 15
Classification of Matter

2. Section 1: Composition of Matter
Substance:
Either an element or a compound
Element:
Substance made of all the same type of atom
Ex: nugget of gold, piece of lead
Compound:
Substance made of two or more types of atoms combined in a fixed proportion
Ex: water (H20), table salt (NaCl)

3. Section 1: Composition of Matter
Mixture:
Made of 2 or more substances that can be separated by physical means
Heterogeneous mixture:
Mixture of different and easily distinguishable materials (ex: trail mix)
Homogeneous mixture:
Contains 2 or more gaseous, liquid, or solid substances blended evenly
Also called a solution (ex: soft drink)

4. Section 1: Composition of Matter
Colloid:
Heterogeneous mixture with larger particles that never settle
Colloids scatter light in the Tyndall effect
Ex: paint, fog
Suspension:
Heterogeneous mixture containing a liquid in which visible particles settle
Ex: muddy pond water

5. Section 2: Properties of Matter
Physical property:
characteristics of a material which can be observed without
changing the identity of the substances in the material
examples: color, shape, size, melting point, and boiling point
1. Appearance—physical description of a substance
2. Behavior—how a substance acts; for example, magnetism, viscosity, ductility
3. Physical properties such as size and magnetism can be used to separate mixtures.

6. Section 2: Properties of Matter
Physical change:
change in a substance’s size, shape, or state of matter
substance does not change identity when it undergoes a physical change
Distillation:
a process for separating a mixture by evaporating a liquid and condensing its vapor

7. Section 2: Properties of Matter
Chemical property:
characteristics of a substance indicating that it can change chemically
for example:
flammability or light sensitivity of a substance

8. Section 2: Properties of Matter
Chemical Change:
When one substance changes to another substance.
Some chemical changes are indicated by temperature change, smell, or bubble formation.
Other chemical changes occur very slowly such as the formation of rust.
Chemical changes can be used to separate substances such as metals from their ores.

9. Section 2: Properties of Matter
Weathering of Earth’s surface involves both physical and chemical changes.
Physical—big rocks split into smaller ones; streams carry rock particles from one location to another
Chemical—Chemical changes can occur in rocks when calcium carbonate in limestone changes to calcium hydrogen carbonate due to acid rain.

10. Section 2: Properties of Matter
Law of Conservation of Mass
Mass of all substances present before a chemical change equals the mass of all substances after the change.