SIGNS OF A CHEMICAL REACTION

FORMATION OF:SIGN EXPLANATION SITUATION PICTURE

GAS FORMATION When 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 FORMATION When 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

CHANGE INSIGN EXPLANATION SITUATION PICTURE

COLOR CHANGE When 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 CHANGE When 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