Download
1 / 8
80 likes | 208 Vues
Compounds . Pgs. 58 - 61. What is a Compound?. Elements are not always found in their natural state. They undergo chemical changes fairly easily and are found combined with other elements as compounds.
E N D
Compounds Pgs. 58 - 61
What is a Compound? • Elements are not always found in their natural state. • They undergo chemical changes fairly easily and are found combined with other elements as compounds. • A compound is a pure substance composed of two or more elements that are chemically combined. • Ex. Salt, water, sugar, carbon dioxide, baking soda
Elements Combine in a Definite Ratio • Compounds are not random combinations of elements. • They form in a specific ratio according to their masses. • Water has a ratio of 1 gram of hydrogen to 8 grams of oxygen. • All water has this same mass ratio.
Every Compound has a Unique Set of Properties • Each compound has its own physical properties. • Compounds can be identified by their chemical properties as well. • Compounds have different properties from the elements that formed them. • Ex. Sodium + Chlorine = Salt • Sodium is a metal, chlorine is a poisonous gas, and salt is safe white nonmetal solid.
Compounds Can Be Broken Down • Some compounds can be broken down into elements through chemical changes. • Ex. Mercury oxide breaks down into mercury and oxygen gas. • Others can undergo chemical changes to form simpler compounds. • Ex. Carbonic acid can break down into carbon dioxide and water
Compounds Cannot Be Broken Down Physically • The only way to break down a compound is through a chemical change. • Filtering, grinding, and breaking are all physical changes. • The compound will keep its identity through those processes.
Compounds in Nature • Proteins are compounds used by all living things. • Proteins have nitrogen that both plants and animals can use once the protein is broken down into simpler substances. • Carbon dioxide is another important compound for life. • Animals exhale it and plants take it in to make food and other compounds.
Compounds in Industry • Nitrogen can be combined with hydrogen to form ammonia. • Ammonia is used in fertilizers for plants. • Other compounds can be things like medicines, food preservatives or synthetic fibers. • Compounds found in nature are not usually the raw material needed by industry. • Ex. Aluminum is found as aluminum oxide. • Aluminum is used to make cans, airplanes, and building materials.
