1. Matter: Physical vs. Chemical

2. Properties of Matter
Characteristics that enable us to distinguish one kind of matter from another.
How can we distinguish hydrochloric acid from water?

3. Types of Properties Extensive Intensive
Depends on the amount of matter
e.g., volume, mass, amount of energy (cal)
Intensive
Does not depend on the amount of matter
e.g., melting point, boiling point, density, conductivity

4. Physical & Chemical Properties
Physical Property
Can be observed or measured without changing a substance’s composition.
Demo- Sand… What do you know about sand? Physical & Chemical Properties
Demo: Ghost Crystals, Colorful Mixing Demo, Tarnished Silver, Magic Sand

5. Physical Properties Boiling Point Melting Point Color Density
Malleability
Conductivity
Magnetism
Hardness
Ability to transmit light

6. Physical & Chemical Properties
Chemical Property
Can only be observed by changing the composition of the material
Changes its identity

7. The ability of a substance to…
Chemical Properties
The ability of a substance to…
Rust
Decay
Burn
Ferment
React with acid, base, or water

8. Properties of Water Water expands as it freezes. (Physical)
Hydrogen peroxide, H2O2 can decompose to produce water.
(Chemical)
Water boils quicker in Denver, CO than at the beach.
When an electrical current is passed through water, elemental hydrogen and oxygen are produced.
Salt can dissolve in water.

9. Physical & Chemical Changes
Physical Change
Will change the visible appearance, without changing the composition of the material
Changes that effect only physical properties.
Does not change the composition!

10. Physical Changes Physical changes are usually reversible Crush Boil
Diffuse
Condense
Osmosis
Cut
Split
Crack
Boil
Melt
Freeze
Distillation
Sublimation
Expand
Demo: Chalk, Shredding paper

11. Physical & Chemical Changes
Changes that involve a change in the composition of the substance.
New matter is formed

12. Chemical Changes Chemical Changes are usually NOT reversible Ferment
Decay/Decompose
React with acid, base, or water
Neutralize
Rust
Digest
Tarnish
Explode / Burn
Ignite
Cook
Chemical Changes
are usually
NOT reversible
Rusting of a car

13. 2H2O  2H2 + O2 Reactants the stuff you start with
Products- what you make
Arrow points from the reactants to the new products
The products will have NEW PROPERTIES different from the reactants you started with

14. Indicators of Chemical Change
Color Change
Gas produced
Temperature change
Light produced
Precipitate forms
Irreversibility
Not easily reversed!

15. Indicators of Chemical Change
Color Change
Very hard to reverse
Think about cooking an egg

16. Indicators of Chemical Change
Gas produced
Bubbles are produced
Careful  there are examples of bubbles that are not chemical – boiling water bubbles
Physical change  Water vapor starts to form inside the liquid in the form of bubbles

17. Indicators of Chemical Change
Temperature change
Heat given off- Exothermic
Feels hot
Feel someone after they workout  they’re hot
Heat absorbed- Endothermic
Feels cool
Sweating while working out

18. Indicators of Chemical Change
Light produced
Striking a match  flame produced
Fireworks

19. Indicators of Chemical Change
Precipitate forms
2 liquids  solid + liquid

20. Law of Conservation of Matter
In any physical or chemical change, matter is neither created nor destroyed.
During any chemical reaction, the mass of the products is always equal to the mass of the reactants

21. Law of Conservation of Matter
All the mass can be accounted for!!
Burning of wood results in products that appear to have less mass as ashes.
Where is the rest??