change it can be physical or chemical. physical change put a can of cola in the freezer. the water...

14
Change It can be Physical or Chemical

Upload: julie-hopkins

Post on 26-Dec-2015

216 views

Category:

Documents


0 download

TRANSCRIPT

Change

It can be Physical or Chemical

Physical Change

Put a can of cola in the freezer.

The water in the cola turns to ice

It pushes on the can and may explode.

Cleaning up that mess is not so nice.

Now ice seems different than water.

But its true identity’s the same.

What do you say when you see this kind of thing?

You call it a Physical Change

Change

Change, its everywhere you go

Change, it maybe fast or slow

Change , You can’t deny it But you can learn to classify

it.

ChangeLight a match and start a candle burning.

See how it gives off heat and light

Don’t stick your finger in that hot wax.

People who do that aren’t too bright.

The Wax is doing more than melting

Its’ atoms move around and rearrange.

CO2 and water are produced when it burns

You call that a Chemical Change.

Change

Change, its everywhere you go

Change, it maybe fast or slow

Change , You can’t deny it But you can learn to classify

it.

Change

Physical Change

During a physical change the matter is manipulated in shape, size or appearance however the atomic or molecular arrangement stays in tack.

The identity of the object remains the same.

Chemical Changes

A CHEMICAL CHANGE ALWAYS RESULTS

IN SOMETHING

NEW BEING CREATED.

Something NEW means you will have a different pure substance

Chemical Changes

There are 5 basic types of chemical changes

1. Definite Color change (not a blending)

2. Production of a gas

3. Absorption or Release of Heat

4. Production of Light

5. Formation of a Precipitate

Chemical Change

1. Definite Color change (not a blending): Dramatic change in the color of a substance indicates a new substance is present. Examples: Iron rusting it changes from dull gray to an orange.Leaves changing.Lemon juice in Ice Tea.

Chemical Change

2. Production of a gas: No not that kind of gas. When there is a chemical change sometimes gas is released. This gas is the result of the chemical reaction and the chemical change. When you mix baking powder with vinegar a gas is let loose and it bubbles. That gas is the product of the baking soda and vinegar mixing.

Chemical Change

3. Absorption or Release of Heat: Burning wood is a classic chemical change. When wood burns it becomes ash and it produces heat. This heat is a product produced during the chemical change.

Types of Heat Reactions a. Exothermic – Release of energy.b. Endothermic – Absorption of energy.

Chemical Change

4. Production of Light: Glow sticks are very common in showing that light is an indicator of a chemical change. Among other things, the lights from fireworks and the light from lightning bugs are also products from a chemical change.

Chemical Change

5. Formation of a Precipitate : When two liquids combine chemically often there is a solid product that is released. When that solid is insoluble {unable to dissolve in solution} the solid will “fall out” of the solution. The solid is called the precipitate and it indicates that a chemical change has occurred.