Chemistry 112Chemistry 112

Elements and CompoundsElements and Compounds

What’s the difference?What’s the difference?

Elements are the simplest form of matter.Elements are the simplest form of matter. They have a unique set of propertiesThey have a unique set of properties

A compound is a substance that contains two A compound is a substance that contains two or more elements chemically combined in a or more elements chemically combined in a fixed proportion.fixed proportion.

Compounds cannot be separated by physical Compounds cannot be separated by physical means, only chemical.means, only chemical. Elements cannot.Elements cannot.

How do you breakdown a How do you breakdown a chemical compound?chemical compound?

Chemical changes are required for the Chemical changes are required for the breakdown of chemical compounds.breakdown of chemical compounds.

Chemical changes give products that are Chemical changes give products that are chemically different from the reactants.chemically different from the reactants.

How are compound sentences like How are compound sentences like chemical compounds?chemical compounds?

Substances and MixturesSubstances and Mixtures

If the composition of the material is fixed, If the composition of the material is fixed, the material is a substance.the material is a substance. Elements and compounds.Elements and compounds.

If the composition of the material varies, If the composition of the material varies, the material is a mixture.the material is a mixture. Homogeneous and heterogeneous mixtures.Homogeneous and heterogeneous mixtures.

Symbols and FormulasSymbols and Formulas

Chemical symbols are used to represent Chemical symbols are used to represent elements.elements. Na, O, S, AuNa, O, S, Au

and chemical formulas are used to and chemical formulas are used to represent compounds.represent compounds. NaCl, HNaCl, H22O, COO, CO22, CaCO, CaCO33

To be completed:To be completed:

Questions 20 – 27, pg. 52Questions 20 – 27, pg. 52