Physical vs
Chemical properties
What are some examples of physical properties?????
- Colour
- Melting point
- Boiling point
- Size
- Shape
- Smell
- State (solid, liquid, or gas)
What are some examples of Chemical properties?????
Physical Change vs Chemical Change
Classify each of the following as a
1) physical change or 2) chemical change
A. ____ a burning candle
B. ____ melting ice
C. ____ toasting a
marshmallow
D. ____ cutting a pizza
E. ____ Braiding your hair
Evidence of a chemical reaction
You usually need more than one of the above characteristics to be considered a chemical change!
Examples
mixing vinegar & baking soda
burning a piece of wood
soured milk
cooking food/
making toast
Was that a chemical Reaction?
Why or why not? What evidence did you see?
Chemical Reactions
What is a chemical property?
What is a physical property?
Physical properties can be observed or measured without changing the physical state of the substance.
What is a chemical Change/
Reaction?
A chemical change takes place when two or more substances interact to form a new substance.
Physical Changes....
- Changes to matter in which composition of the matter stays the same.
- Many can be reversed.
- Example: Folding paper/ripping paper
These reactions are not easily reversed!
(acidic or basic)
- Heat of Combustion
- Rusting
BRAIN BREAK!
Chemical properties are characteristics of a material that become evident when the material undergoes a chemical reaction or chemical change.
What are chemical properties?
Trivia Break
Which animal can go longer
than a camel without water?
- Light
- Odor
- Fizzing/foaming
- Colour changes
- Precipitate - a solid that forms from a solution
during a chemical reaction
Kangaroo Rats!
Describing chemical reactions
The Law of Conservation of Mass states...
- Matter is neither created nor destroyed!
- That in a chemical reaction, the total mass of the reactants must equal the total mass of the products
Chemical equations use chemical formulas and other symbols instead of words to summarize a reaction
The Law of Conservation of Mass...
- Reactants - substances you have at the beginning
- Products - new substances produced when the reaction is complete
pizza dough + tomato
sauce+cheese
Kind of like a recipe....
pizza dough + tomato sauce+cheese
Just like in our recipe...
We will continue this when
we discuss balancing
chemical equations....