1. Bell work: 12/2/13
Would you classify eating turkey as a chemical change or physical change? Why?

2. Physical & Chemical Changes
Changing Matter
Physical & Chemical Changes

3. Matter has properties
Two basic types of properties that we can associate with matter.
Physical properties
Chemical properties

4. Physical Properties
Anything that can be observed without changing the identity of the substance. (Tends to be measurable.)
melting point
density
boiling point
thermal conductivity
electrical conductivity
ductility
color
malleability

5. Physical Changes Do NOT CHANGE THE TYPE OF MATTER
Nothing new or different is formed
Could be a change in:
Mass
Volume
Density
Change in state
Color
Shape
Size

6. Examples of Physical Changes
Boiling
Freezing
Dissolving
Breaking
Making a mixture
2 or more types of matter (substances) mixed together
Not in specific amounts
Can be separated physically

7. Chemical Properties
The way a substance may change or react to form other substances
heat of combustion
Reactivity to other chemicals
reactivity with water PH
Oxidation
Flammability
Chemical properties of matter describes its "potential" to undergo some chemical change or reaction by virtue of its composition. What elements, electrons, and bonding are present to give the potential for chemical change.
It is quite difficult to define a chemical property without using the word "change". Eventually you should be able to look at the formula of a compound and state some chemical property. At this time this is very difficult to do and you are not expected to be able to do it.
For example hydrogen has the potential to ignite and explode given the right conditions. This is a chemical property.
Metals in general have they chemical property of reacting with an acid. Zinc reacts with hydrochloric acid to produce hydrogen gas. This is a chemical property.

8. Picture from www.chem4kids.com
Chemical Changes
The composition of the substance changes.
The substances present at the beginning of the change are not present at the end; new substances are formed. The change cannot be “undone.”
Picture from

9. Chemical Changes Evidence of a chemical change Formation of gas
Formation of precipitate
Change in color
Change in energy
Alka-Seltzer: (Baking soda or sodium bicarbonate) NaHCO3 + Citric acid ---> CO2 + H2O + Sodium Citrate

10. Chemical Changes
Atoms are re-arranged, NOT created or destroyed

11. Law of Conservation of Mass
Mass is conserved  amount of atoms cannot change
Nothing is created or destroyed