1. 2.2 What are some ways to describe matter?
Concept 2: Matter can be described by its chemical properties
Concept 3: Matter can be described based on physical and chemical changes
Name:______________________________
Date:______________________________

2. Chemical Properties: Qualitative Observations
Matter can also be described using chemical properties
Chemical property describes the ability of matter to react.
Chemical properties can only be observed in a chemical reaction.
Reactivity with acids:
Some substances react vigorously with acids and others do not
Example: baking soda and vinegar produce a gas

3. Chemical Properties: Qualitative Observations
Reactivity with oxygen:
Substances in some foods react with oxygen when exposed to air
Example: avocadoes turning brown
Combustibility:
Some material will catch fire and burn in the air
Example: burning wood
Lack of reactivity:
Some substances do not react with other substances are known to be “inert”
Example: helium in balloons

4. Matter can be described based on physical and chemical changes.
Chemical Change: cooking toast
Physical Change: Boiling Water
Chemical and Physical Change: cooking bacon
Refer to page 121 in the textbook

5. Describing Matter: Physical Changes
Physical Change is a change that alters a substance without changing its chemical identity or composition.
Ex: crumpling up a piece of aluminum foil, folding a piece of paper into a bird
Can you think of another example of physical change?
_____________________________________________
Changing the state of matter of a substance is also a physical change
Example: freezing water into ice, boiling water until it forms steam.

6. Describing Matter: Chemical Changes
A chemical change can also be known as a chemical reaction
In a chemical reaction we have reactants and products
reactants products
During chemical changes, new substance are going to be produced
Example:
steel forming rust
food rotting
gasoline producing smoke

7. Describing Matter: Chemical Changes
Can you give an example of a chemical change?
_________________________________________
Evidence of new substances forming:
Change in colour
Change in texture
New smells
Release of gas
Change of energy in the form of heat

8. Law of Conservation of Mass
Antoine and Marie Anne Lavoisier carried out many chemical reactions and found that the mass does not change during a chemical reaction.
The law of conservation of mass states:
mass of the reactants = mass of the products
Antoine and Marie Anne Lavoisier

9. Law of Conservation of Mass

10. Matter can be classified based on how it responds to physical and chemical changes
Matter can either be pure substances or mixtures
Most of the matter in the world is a mixture
Matter
Mixture
Pure Substance
Elements
Compounds

11. Types of Matter: Mixtures
A mixture is two or more different kinds of particles
Example: salt water
Salt can be separated from water by evaporation
Example: iron and sand mixture
Iron can be separated from sand by using a magnet

12. Types of Matter: Pure Substances
In a pure substance, all the particles look alike
There are two different kinds of pure substances
Compounds
Elements
Diagrams:
CAN be broken down further into elements by chemical means
CANNOT be broken down further
Examples: water (H2O), carbon dioxide (CO2), Glucose (C6H12O6)
Examples: solid gold, solid silver

13. Is it a mixture or a pure substance?
element
mixture
Pure substance
mixture
Pure substance
mixture
compound

14. Is it a mixture or a pure substance?
compound
compound