1. Chapter 10 Lesson 3
Chemical Changes

2. Chemical Changes Lesson 3
Vocabulary
Chemical Change: a change that causes different kinds of matter to form.

3. What are chemical changes?
Not all chemical changes are useful.
A car made from iron might rust.
Rust is very different from iron. It is weaker and it peels.
Food spoils as a result of chemical changes. Materials in food can break down and form new materials.
When this happens, food
might change color or smell bad.

4. What are chemical changes?
A chemical change causes different kinds of matter to form.
The properties of the new matter are different from those of the original materials.
Chemical changes happen every day. Your body uses chemical changes to break down the food you eat.
Cooking uses chemical changes. Cake batter changes when you bake it. You
know it has changed because it
feels and tastes different.

5. What are the signs of a chemical change?
A chemical change happens when different materials are put together .
Light and Heat:
A burning log changes into carbon dioxide gas and ash.
As the log burns, it releases light and heat.

6. Formation of Gas:
The formation of a gas can be a sign of a chemical change.
When you add baking soda to vinegar, carbon dioxide gas forms.
As this gas escapes from the liquid, bubbles form.

7. Color Change:
A color change shows that a chemical change has happened.
The Statue of Liberty used to be the same color as a penny. It turned green as a result of a chemical change.