COMPOUNDS Chapter 5 - 2

Compounds: Made of Elements A compound is a pure substance composed of two or more elements that are chemically combined.

CHEMICAL REACTIONS FORM COMPOUNDS A chemical reaction is the process by which substances change into new substances. The atoms are rearranged into new combinations.

Properties of Compounds Each compound has its own physical properties like melting point, density, and color. They can also be identified by their different chemical properties, such as reaction to acid and oxygen.

Properties: Compounds vs. Elements A compound has properties that are different than the elements that form them.

Ratio of Elements Elements combine in a definite ratio to form a compound. Examples: H2O, CO2, HCl, NaCl

Breaking Down Compounds Some compounds can be broken down into their elements by chemical changes. Opening a carbonated drink lets the carbonic acid break down into simpler compounds- carbon dioxide and water

Methods of Breaking Down Compounds The only way to break down a compound is through a chemical change. Sometimes energy needs to be added for a chemical change to happen. Examples: apply heat or apply an electrical current.

Compounds in Industry Compounds found in nature are not usually the raw materials needed by industry. These compounds must be broken down to provide the raw materials. Example: aluminum oxide

Compounds in Nature Proteins are compounds found in all living things. Carbon dioxide is another compound that is used in photosynthesis.

THE END OF CHAPTER 5 - 2