1. Compounds and Mixtures

2. Compound
Substance made of two or more elements that combine chemically and display properties that are unlike those of the individual elements that make up the substance.

3. Example:
H2SO4 sulfuric acid
Made up of:
Hydrogen
Sulfur
Oxygen

4. CuSO4 3 How many elements are found in this compound?
How many atoms of each element are present?
1 copper (Cu)
1 sulfur (S)
4 oxygens (O)

5. The subscript “2” applies to everything in the parentheses.
And what about this one…?
Mg(OH)2
The subscript “2” applies to everything in the parentheses.
2 atoms of oxygen
1 atom of magnesium
2 atoms of hydrogen
A tiny hint: If you don’t know the symbols, count the capital letters in the formula to determine the number of elements that are present.

6. A MOLECULE
is the smallest whole part of a compound. A molecule may be made up of only one type of element (O2) or a number of different elements (H2SO4).

7. Some substances do not exist as single atoms, but are always paired
Some substances do not exist as single atoms, but are always paired. They are called diatomic molecules.
“di-” = “two” O2
Cl2 F2 H2 N2
Br2 I2

8. A MIXTURE
is made of two or more substances that are mixed together WITHOUT combining chemically. A mixture can be separated back into its original components.

9. RADICAL = A molecular group that acts as a single unit when forming a compound.
Some common radicals are:
NO3 nitrate
OH hydroxides
PO4 phosphate
SO4 sulfate
CO3 carbonate
O oxide

10. Examples of compounds that include a radical in the chemical formula:
NaOH sodium hydroxide
CaCO3 calcium carbonate

11. Prefixes commonly used in compound names:
Tetra-
Uni- or mono-
Di- or bi-
Pent-
Tri-

12. Carbon tetrachloride = CCl4
Examples:
Carbon Dioxide = CO2
Dioxide = 2 oxygen atoms
Di- or bi-
Carbon tetrachloride = CCl4
Tetrachloride = 4 chlorine atoms
Tetra-