Physical and Chemical CHANGES

Physical changes are all about energy and states of matter

In a physical change there is only a change of state—thermal energy is added or removed. The new substance has the same chemical properties as the old one. No new substance(s) are produced. Physical changes can be reversed.

SOLIDS _LIQUIDS_ GASES_ PLASMA + energy -energy The Staircase of Phase Change Subtracting energy slows molecule motion, causing matter to go back down the stairs to a lower energy level. Adding energy speeds up molecule motion, causing matter to move up a level on the stairs.

Chemical changes happen on a molecular level.

Plus, you cannot get the original materials back easily. In a chemical change one or more NEW substances are created. The new substance is different from the original. It has properties that are different than those of the starting materials.

Identify the following events as: Physical Change Ask yourself: 1.Is the material still the same basic material? 2.Is it just a change of state or phase? 3.Is it really new or different material? 4.Can it be easily reversed? Chemical Change Ask yourself: 1.Are there any new or different substances? 2.Is the material different from the original? 3.Are the chemical properties different? 4.Can it be easily reversed?

glass breaking hammering wood together to build a playhouse melting butter for popcorn separating sand from gravel spoiling food mixing Kool-Aid powder into water bleaching your hair fireworks exploding squeezing oranges to make orange juice frying an egg pouring milk on your cereal burning leaves making salt water to gargle with cream being whipped burning toast freezing chocolate covered bananas melting Popsicles cooking spaghetti

Glow Sticks

Cooking applesauce

Whipping cream

Adding milk to cereal

Burning leaves

Making frozen chocolate bananas

Hammering wood together

Bleaching your hair

Dissolving Kool-Aid in water

Spoiled food

Melting a popsicle

Breaking a glass

Exploding fireworks Fourth of July Ashland, KY

Melting butter for popcorn

Cooking an egg

Separating sand and gravel

Burned toast

Squeezing oranges for juice

Quiz Time!

1. In a physical change there is only a change of state—_______ is added or removed. 2. The new substance has the same _________ properties as the old one. 3. No _____ substance(s) are produced. 4. Physical changes are easily ________. Use these to complete the questions: Chemical Energy New Reversed

1.In a chemical change one or more _____ substances are created. 2. The new substance is different from the _________ substance. 3. It has properties that are _______ than those of the starting materials. 4. You _______get the original materials back easily. Use these to complete the statements: Cannot Different New Original

The END