1. Physical and Chemical Changes
Lesson 3
February 3rd, 2011

2. Physical Change
In a physical change, the substance involved remains the same (chemically). The substance may change form or state, however. All changes of state are physical changes.

3. Physical Change
Examples: Dissolving a substance in a liquid, breaking something.
NOTE: Most physical changes can be reversed

4. Observing Chemical Properties (3)
A chemical property describes the ability of a substance to change into a new substance or substances.

5. In order to view a chemical property a chemical change must occur.
Chemical change - the formation of a new substance or substances with new properties.
A chemical reaction is a process in which a chemical change occurs.
Chemical properties include how a substance interacts with other substances

6. Chemical Properties
1. Combustibility is the ability of a substance to burn. In order to burn a substance requires Oxygen

7. Chemical Properties
Light sensitivity is a chemical property of that can cause new substances to form when light hits it.

8. Chemical Properties
3. Reacting with an acid is a chemical property where when acid is poured on a substance it produces a gas and bubbles.

9. Clues that a chemical change has occurred
Evidence of Chemical Change
Example
Picture
Change in Colour
Metal is silver- coloured; rusted metal is brown

10. Clues that a chemical change has occurred
Evidence of Chemical Change
Example
Picture
Bubbles appear or a gas is formed
Sodium bicarbonate creates a gas when dropped in water.

11. Clues that a chemical change has occurred
Evidence of Chemical Change
Example
Picture
Heat or light is produced or absorbed
A burning candle gives off light and heat

12. Clues that a chemical change has occurred
Evidence of Chemical Change
Example
Picture
A solid is formed
Precipitate

13. Clues that a chemical change has occurred
Evidence of Chemical Change
Example
Picture
The change cannot be reversed
A fried egg cannot be converted back to a raw egg.

14. WHMIS, HHPS, and MSDS labels provide information about what might happen when chemical changes occur. This information is intended to protect you.

15. Physical and Chemical Changes Worksheet
Complete
If time permits we will start the lab.