1. Physical & Chemical Changes
Changing Matter
Physical & Chemical Changes

2. What different ways can we differentiate between my sisters?
Properties
How we identify something.
All substances have properties that we can use to identify them. For example we can identify a person by their face, their voice, height, finger prints, DNA etc.. The more of these properties that we can identify, the better we know the person. In a similar way matter has properties - and there are many of them. There are two basic types of properties that we can associate with matter.

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. 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.

6. Matter can be changed two ways
Physically
Physical reaction
Physical change
Chemically
Chemical reaction
Chemical change

7. 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

8. 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

9. 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

10. Chemical Changes Evidence of a chemical reaction Formation of gas
Formation of precipitate
Change in color
Change in energy
Endothermic Absorbs heat energy (gets cold)
Exothermic Releases heat energy (gets hot)
Alka-Seltzer: (Baking soda or sodium bicarbonate) NaHCO3 + Citric acid ---> CO2 + H2O + Sodium Citrate

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

12. Law of Conservation of Matter
Matter is conserved  type of atoms does not change
Nothing is created or destroyed

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