Chemistry—The study of the properties of matter and how matter changes. Chemistry—The study of the properties of matter and how matter changes. Element—a substance that cannot be broken down into any other substances by chemical or physical means. Element—a substance that cannot be broken down into any other substances by chemical or physical means. Example: Carbon--C Example: Carbon--C All the matter around you is composed of one element or a combination of two or more elements. All the matter around you is composed of one element or a combination of two or more elements. Atoms—Smallest part of an element. All atoms of an element have the same chemical properties of atoms of other elements. Atoms—Smallest part of an element. All atoms of an element have the same chemical properties of atoms of other elements. Molecule—a combination of two or more atoms. Some molecules are made of atoms that are alike, as is oxygen gas (O 2 ) that you breathe. Molecule—a combination of two or more atoms. Some molecules are made of atoms that are alike, as is oxygen gas (O 2 ) that you breathe.

Compounds and Mixtures Compounds—A substance made of two or more elements chemically combined. They have a chemical formula. Compounds—A substance made of two or more elements chemically combined. They have a chemical formula. Examples: Sugar, Salt Examples: Sugar, Salt Mixtures—Substances that are mixed, but NOT chemically combined. They do not have formulas and can be separated by physical means. Mixtures—Substances that are mixed, but NOT chemically combined. They do not have formulas and can be separated by physical means. Examples: Dixie Cheeseburger, Iron and Sand Examples: Dixie Cheeseburger, Iron and Sand

Heterogenous mixture—mixture you can see the different parts Heterogenous mixture—mixture you can see the different parts Example—lasagna Example—lasagna Homogeneous mixture—mixture that looks the same throughout Homogeneous mixture—mixture that looks the same throughout Example-milk, Crest toothpaste Example-milk, Crest toothpaste

Changes Physical changes—A change that alters the form or appearance of a material, but it does not change the material into a new substance. Physical changes—A change that alters the form or appearance of a material, but it does not change the material into a new substance. All phase changes are physical. All phase changes are physical. Examples: tearing paper, evaporating water. Examples: tearing paper, evaporating water. Chemical changes—A change in matter that produces a new substance. Chemical changes—A change in matter that produces a new substance. Example: Burning wood Example: Burning wood

Signs of Chemical changes: Signs of a chemical change: Signs of a chemical change: A precipitate forms. (A solid that forms when two liquids are mixed.) A precipitate forms. (A solid that forms when two liquids are mixed.) Color Change Color Change Gas Production (You should see bubbles.) Gas Production (You should see bubbles.) Changes in temperature Changes in temperature Changes in Properties Changes in Properties