ChemistryChemical/Physical Properties & Changes

If H2O is the formula for water, what is the formula for ice? H2O cubed.

What is Matter?

Think and Discuss

What is Matter?

• Matter is any substance that has both mass and volume.

• Almost everything around us is matter including air and other gases.

• Examples of things that are not considered matter are light, heat, other types of energy.

Properties

• Properties are the characteristics used to identify a substance.

• Examples include, color, taste, smell, dimensions, density, etc.

Types of Properties

1. Chemical Properties

2. Physical Properties Quantitative vs.

Qualitative Properties

Properties

• Chemical Property – Describes the ability of a substance to form one or more different substances

–The substance is combustible (will burn)–The substance will react with an acid

• Physical Property – Describes a substance –Height, weight, colour, etc.–Includes qualitative and quantitative properties

Types of Properties

• Qualitative properties are descriptive properties.– Example- The car is red.

• Quantitative properties are based on a number or measurement.– Example – It is 5°C outside.

Types of Properties

Please turn to the Physical and Chemical Properties Handout

Chemical vs Physical Change

• A chemical change results in new substance being formed.

• A physical change results in the same substance with altered physical properties.

Examples

Chemical Physical_____

• Burning wood Sawing wood

• Decomposing water Freezing water

• Nail rusting Cleaning rust with steel wool

Chemical Change Clues

1. A gas is given off

2. A color change occurs.

3. A precipitate (solid) is formed

4. Heat is absorbed or given off.

5. Also, difficulty in reversing a change hints at a chemical change.

• Keep in mind these are only clues that a chemical change may have taken place. Proof still depends on a new substance being formed with new properties.

Is it a Physical or Chemical Change?

The following video will help explain the differences between Physical and Chemical Changes.