1. 3.3 Compounds and Mixtures
Vocabulary word
Definition
formula
substance
compound
mixture

2. 3.3 Compounds and Mixtures
The food we eat, the materials we use and all matter can be classified by compounds or mixtures.
Substance- matter that has the same composition and properties throughout. An element such as a bar of gold is a substance.
Compound- a substance whose smallest unit is made up of atoms of more than one element bonded together.
Properties that are different from the elements that make them up. Ex: water, H2O.
Mixtures- when two or more substances (elements or compounds) come together but don’t combine to make a new substance.
Ex: mixing sand and water together does not change its identity. They are not chemically bonded together.
Water is different from the elements that make it up, just as hydrogen peroxide is different from water.

3. 3.3 Compounds and Mixtures
Compounds Have Formulas
Chemical formulas:
Which elements make up a compound
The subscript number written below and to the right of each element’s symbol tells how many atoms of each element are present
Ex: H2O has two atoms of hydrogen and one atom of oxygen.
Ex: H2O2 has two atoms of hydrogen and two atoms of oxygen.
*Propane has three carbon and eight hydrogen atoms. What is its chemical formula?

4. 3.3 Compounds and Mixtures
Homogeneous Mixtures
Homogenous means “the same throughout.”
You cannot see the different parts in this type of mixture
Heterogeneous Mixtures
Larger parts that are different from each other
You can see the different parts in this type of mixture
Ex: sand and water