819 Identify the common outcomes of all chemical changes.

Identify the common outcomes of all chemical changes. Key concepts/skills: Level 1: Define key vocabulary. Level 2: Identify the parts of a chemical equation. Level 3: Identify the common outcomes of all chemical changes including chemical and physical property changes, endothermic and exothermic, conservation of mass, cannot be reversed by physical means.

Key vocabulary Chemical equation reactant product Yield flammability reactivity Physical properties chemical properties endothermic Exothermic Chemical change

I. Chemical Changes A. When substances react to form completely new substances with new chemical and physical properties. 1. How to recognize a chemical change. a. Gas formation b. Solid formation in a liquid c. Energy change d. Color change Identify the common outcomes of all chemical changes.

II. Chemical equation – a series of symbols and formulas that show what happens during a chemical reaction. A. Reactant + reactant > Product + Product (yields)

III. The amount of Matter A. The amount of matter that starts a reaction is the same as the amount of matter produced B. The number of atoms is the same beginning to end C. 10 atoms + 15 atoms > 25 atoms Identify the common outcomes of all chemical changes.

IV. Chemical Properties A. Flammability – how easily a substance burns B. Reactivity – how easily a substance reacts with others C. Chemical props after reaction are completely different than before D. Chemical Props. > New chem. Props. Identify the common outcomes of all chemical changes.

V. Physical Properties A. Size, Shape, Color, Odor, Texture, things that can be observed with senses B. All Physical properties change during a chemical reaction C. Physical Properties > New Physical Properties Identify the common outcomes of all chemical changes.

VI. Energy A. Energy is either absorbed by a chemical reaction or released B. Exothermic reaction – release energy as heat or light C. Endothermic reaction – absorb energy as heat or light Identify the common outcomes of all chemical changes.

VII. Chemical Changes cannot be reversed by physical means A. The products of most chemical changes are physically stable B. heat or physical stress cannot reverse a chemical reaction

Common Outcomes of Chemical Changes 1. Physical change (color, texture, odor, size, shape) 2. Chemical change (flammability, reactivity) 3. Reactants > (yield) Products 4. Amount of matter stays same 10 atoms + 15 atoms = 25 atoms 5. Endothermic or Exothermic 6. Cannot be reversed by physical means Identify the common outcomes of all chemical changes.