Objectives: Explainhow elements make up compounds. Describe the properties of compounds. Explain how a compound can be broken down into its elements Giveexamples of common compounds. Bellringer The word compound refers to something that consists of two or more parts. How might you make a compound using elements? What are some compounds that you know?
Compounds: Made of Elements Compound pure substance composed of two or more elements that are chemically combined. Molecule Particle of a compound Formed when atoms of two or more elements join together. The Ratio of Elements in a Compound Elements join in a specific ratio according to their masses to form a compound Example, every sample of water has a 1:8 mass ratio of hydrogen and oxygen. Acetic acid Carbon Hydrogen Oxygen Water Hydrogen Oxygen Baking soda Sodium Hydrogen Oxygen Carbon
Properties of Compounds Each compound can be identified by its physical and chemical properties Compounds Versus Elements A compound has properties that differ from those of the elements that form it. Sodium
Dissolves in water
Safe to eat
Breaking Down Compounds Compounds can be broken down into their elements or into simpler compounds by chemical changes Methods of Breaking Down Compounds Energy is needed for a chemical change to occur Two ways to add energy apply heat apply an electric current
Compounds in Your World Compounds in Nature Proteins Carbon dioxide Carbohydrates Compounds in Industry Some compounds must be broken down for use in industry. Medicines food preservatives synthetic fabrics protein air carbohydrates medicine Food preservative Synthetic fabrics