1. What do you think a chemical property is?
Friday, 9/22/ Day 2
Science Warm
Ups
AR Book under desk
Agenda
1. Please have these
Items on your desk.
Science notebook
Fill out your Agenda.
Science Starter:
What do you think a chemical property is?
What signs do you think you will see if a chemical change is occurring?

2. Physical versus Chemical Properties

3. Reviewing MATTER Matter: anything that has mass and takes up space
Mass – the amount of matter in something
Volume – the amount of space something occupies
Which of the following is matter?
A car?
A box?
You?

4. What is a property?
Property: a characteristic of a substance that can be observed

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

6. Physical Property
Physical property: a property that can be observed without changing the identity of the substance.
Examples:
luster
malleability: the ability to be hammered into a thin sheet
ductility: the ability to be stretched into a wire
melting point
boiling point
density
solubility
specific heat

7. Special Physical Properties
Melting point: the temperature at which a substance changes from a solid to a liquid at a given pressure
Boiling point: the temperature at which a substance changes from a liquid to a gas at a given pressure
water = 100oC

8. Physical Changes Do NOT CHANGE THE TYPE OF MATTER
Nothing new or different is formed
Could be a change in:
A. Size
B. Change in state
C. Color
D. Shape

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

10. Chemical Properties
Chemical property: a property that can only be observed by changing the identity of the substance
Examples:
flammability
ability to rust
reactivity with vinegar

11. 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

12. Evidence of Chemical Reactions
Chemical Reaction: The process by which the atoms of one or more substances are rearranged to form different substances.
Temperature change
Color change
Gas or solid appears

13.
Bozeman video clip

14. 4. An energy change (Temperature)
Endothermic reaction-a chemical reaction accompanied by the absorption of heat.
Exothermic reaction-a chemical reaction that releases energy. The energy “ex”its. It is the opposite of an endothermic reaction.

15. Example of everyday endothermic reactions

16. Examples of everyday exothermic reactions

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

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

19. Change of Matter::::Physical change: Identity Retained.
This type involves a change in the observable properties of matter without a change of the substance identity.  In most physical change of matter, no bonds are broken between atoms and the identity of the substance is retained.
Example:  Phase Change  
In a phase change matter changes from solid, liquid or solid but the identity of the substance is retained. 
 

20. Change of Matter:::::Chemical change: Identity Changed

This type of change refers to a material changing to a completely different type of material or transformation to a new substance. This process involves bond breaking and bond forming such that material changes identity. 
 
Example:  Decomposition of water.
In the decomposition of water, water molecules H2O are broken down to hydrogen and oxygen.

21. Consider the following examples, which of these are phyiscal and which are chemical change
Heating sugar vs. adding sugar to water
Cutting wood vs. burning wood.
3. The electrolysis of water vs. ice melting.

22. Answers. . . . . . . .. Physical Change Chemical Change
1. Sugar dissolving Sugar heating
2. Cutting Wood Burning Wood
3. Melting Ice Electrolysis of water