1. SIGNS OF A CHEMICAL REACTION

2. FORMATION OF: SIGNEXPLANATIONSITUATIONPICTURE GAS FORMATIONWhen a chemical reaction occurs, two or more substance chemically react and form a gas When an alkali metal and water come together, one of the products is Hydrogen gas PRECIPITATE FORMATIONWhen a chemical reaction occurs, two or more substances chemically react and a solid “rains down” / “falls out” of the reaction when milk and vinegar are mixed together, the milk curdles and substances fall out to the bottom of the container

3. CHANGE IN SIGNEXPLANATIONSITUATIONPICTURE COLOR CHANGEWhen a chemical reaction occurs and the color changes from the original color to the new color. You need another reaction to reverse! When you dye your blonde hair purple, it changes from blonde to purple. To change it back you need another chemical reaction! ENERGY (LIGHT OR HEAT) EXCHANGE When a chemical reaction occurs, heat or light is taken in or given off (endothermic and exothermic reactions) When cooking chicken, I must add heat in order to make it safe to eat ODOR CHANGEWhen a chemical reaction occurs, a noticeable change in smell can be seen. When using Febreeze, Oxygen atoms bond to the smelly compounds and lifts the away so everything smells fresh