1

Pure Substances are either:

a) elements

b) Compounds

Are a substance that cannot be separated into simpler substances by physical means

2

Elements simplest kind of matter

– http://www.privatehand.com/flash/elements.html?ref=nf

cannot be broken down any simpler and still have properties of that element!

all one kind of atom.

92 naturally occurring elements

Arranged in the Periodic Table of Elements by increasing atomic number

3

Symbols & Formulas Elements have a 1 or two letter symbol,

and compounds have a formula.

An element’s first letter always capitalized; if there is a second letter, it is written lowercase.

– Examples: B, Ba, C, Ca, H, He

Some names come from Latin

4

made of two or more atoms, chemically combined (not just a physical blend!)

when broken down, the pieces have completely different properties than the original compound.

– Example: NaCl (salt) »Na is explosive and Cl is toxic but

together it is edible

Compounds

5

Making Compounds

They must always combine in definite proportions (C12H22O11)

The proportions are determined by the number of chemical bonds that can be formed by each atom.

6

Representing Compounds Compounds are represented by chemical

formulas.

– A formula indicates the number and kind of atoms making up a compound.

For example: H2O consists of 2 hydrogen atoms and 1 oxygen atom.

MgSO4 consists of 1 magnesium atom, 1 sulfur atom, and 4 oxygen atoms.

7

Separating Compounds Chemical means must be used to

separate compounds

External energy must be used to separate. The energy could be heat or electricity

Example: Electrolysis- electricity is used to split a water molecule to produce hydrogen and oxygen gas.

2H20 ---------> 2H2 + O2

8

Identify the Type of Substance

Na

H20

CuCl2

O2

Sn

CO2

FeF3

B

Cobalt

Xenon hexafluoride

Gold

Lithium

Zinc nitrate

Hydrochloric acid

Mercury

krypton

9

Compound vs. Mixture

Compound Mixture

Made of one kind of material

Made of more than one kind of material

Made by a chemical change

Made by a physical change

Definite composition

Variable composition

10

Classification of Matter