Chemical and physical properties - Mr Banks...
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Chemical and physical properties MR. BANKS 7 TH GRADE SCIENCE
Transcript of Chemical and physical properties - Mr Banks...
Chemical and
physical propertiesMR. BANKS
7TH GRADE SCIENCE
How can you describe an object if you didn't know
what it is? Describing objects by
using ______
size
shape
color
Texture
Smell
Basically an object's characteristics.
Find an object in the room.
Describe that object in as many
ways as you can think of and
record your description in your
notebook.
Pair up with another student and
have them read your description
and try to guess your object.
What were some of the characteristics you listed
about your object?
Size, weight & mass, shape, odor, color, etc.
Properties of matter
A property is a characteristic of matter (meaning both elements
and compounds) that can be observed.
There are two types of property: physical and chemical.
Physical properties
Physical properties are characteristics of a
substance that can be observed without
changing the chemical identity of the substance.
Density, texture, color, smell, taste, melting point,
boiling point, hardness, solubility, etc.
Physical properties
Things that aren’t physical properties are words or
numbers, what an object is used for, and age.
Humans are very good at utilizing physical properties to identify things.
When you look at oranges, you know that they are oranges because of their color, shape, texture, and smell.
Physical properties
Physical properties can
change.
Ice in your soda melts,
glass breaks, paper is
ripped.
When ice melts in a
drink where does it go?
What does it become?
Is it still water?
Have the properties
changed?
Physical changes
Properties of matter
Chemical property – A
characteristic of a
substance that describes
its ability to interact with
and change into other
substances.
Can only be observed
when a substance
changes.
Examples: Chemical
reactions, burning,
rusting.
Chemical properties
A common chemical property is reactivity.
Reactive to oxygen
Reactive to water
Reactive to other chemicals The other most common chemical property is
radioactivity.
Notice that chemical properties aren’t easy to
observe, like physical properties are.
Chemical properties
Signs of chemical reaction.
Bubbling (making gasses)
Fire
Changes in temperature
Production of an odor
Formation of a solid
Chemical changes alter the identity of a substance.
In other words, a chemical change is when something changes into an entirely different substance.
For example:
Iron rusting
Wood burning
Baking a cake
Spoiled milk
Chemical changes
Compounds
The chemical and physical properties of compounds are
different from the properties of the elements they are
made of.
Soduim, Na Chlorine, Cl
Salt, NaCl
Na Cl
Oxygen, O Hydrogen, H
Water, H2O
H
O
H
1. A. Physical Change
B. Chemical Change
Rusting nails
2. A. Physical Change
B. Chemical Change
Effervescent tablet
3. A. Physical Change
B. Chemical Change
Cutting paper
4. A. Physical Change
B. Chemical Change
Vinegar and Baking soda
5. A. Physical Change
B. Chemical Change
Salt and water
6. A. Physical Change
B. Chemical Change
Breaking glass
7. A. Physical Change
B. Chemical Change
Burning wood
8. A. Physical Change
B. Chemical Change
Ice melting
9. A. Physical Change
B. Chemical Change
Sodium and water
10. A. Physical Change
B. Chemical Change
Boiling water
