Compounds and Mixtures

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.

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

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)

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.

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).

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

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.

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

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

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

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