Download - Properties and Changes
Physical and Chemical
Properties of Matter
What is a physical property of matter?
• A property that can be observed or measured without changing the identity of that matter
• Ex: Color, odor, shape, size, etc.
Thermal Conductivity
Definition:
The ability to transfer thermal energy (heat) to something else
Example:
Coffee in a special cup to prevent heat transfer to our hands
State
Definition:
The form in which matter exists: solid, liquid, gas, or plasma
Example:
Ice = Solid Water = Liquid Helium = Gas Lightning = Plasma
Malleability
Definition:
The ability to be pounded into thin sheets
Example:
Aluminum can be pounded flat to make aluminum foil
Ductility
Definition:
The ability to be drawn into thin wires
Example:
Copper is used to make wires
Example:
Alka-seltzer dissolves in water or sugar dissolves in coffee
Solubility
Definition:
The ability for one substance to dissolve into another substance
Density
Definition:
Mass per unit volume
Example:
Lead is used for fishing weights because it is more dense than water
More information about density...
Density = The amount of matter in a given space or volume
Density = m Mass v Volume
More information about density...
Most substances have a unique density:Water = 1.00 g/mLGold = 19.32 g/mL(See page 13 in your book for a bigger list)
Density < 1 - The object will float in water Density > 1 – The object will sink in water
The Magic Triangle
Answers are expressed in g/cm3
or g/mL
CHEMICAL PROPERTIES
Chemical properties can ONLY be observed AS the substances are changing into different substances.
FLAMMABILITY: A material’s ability to BURN in the presence of OXYGEN
REACTIVITY:How readily (easily) a substance combines chemically with other substances.
Physical and Chemical Changes
Physical changes are those changes that do not result in the production of a new substance. If you melt a block of ice, you still have H2O at the end of the change.
Physical Changes
• Physical changes do not result in the formation of a new substance and are reversible.
• The following are examples of physical changes:• Melting and freezing• Boiling and condensation• Forming a separable mixture
If you break a bottle, you still have glass. Painting your nails will not stop them from being fingernails. Some common examples of physical changes are: melting, freezing, condensing, breaking, crushing, cutting, and bending.
Some, but not all physical changes can be reversed. You could refreeze the water into ice, but you cannot put your hair back together if you don’t like your haircut!
Special types of physical changes where any object changes state, such as when water freezes or evaporates, are sometimes called change of state operations.
Chemical changes, or chemical reactions, are changes that result in the production of another substance.
Chemical Changes Chemical changes result in the formation of
a new substance and tend to be irreversible.
The following observations often suggest that a chemical change has taken place:
Colour change Evolution (release) of gas Temperature change Solution turns cloudy Change of pH
Signs for chemical changes
Color change Gas formation (fizzing/bubbles) Change in light and temperature Precipitate (solid formation)
When you burn a log in a fireplace, you are carrying out a chemical reaction that releases carbon. When you light your Bunsen burner in lab, you are carrying out a chemical CHANGE that produces water and carbon dioxide.
Common examples of chemical changes that you may be somewhat familiar with are; digestion, respiration, photosynthesis, burning, and decomposition.
Physical or Chemical Change?
Painting WoodPHYSICAL
Physical or Chemical Change?
•Burning Paper•CHEMICAL
Physical or Chemical Change?
•Digestion of food•CHEMICAL
Physical or Chemical Change?
•Sugar dissolving in water
•PHYSICAL
Physical or Chemical Change?
•Iron turning red when heated
•PHYSICAL
Physical or Chemical Change?
•Evaporation•PHYSICAL
Physical or Chemical Change?
•A pond freezing in winter
•PHYSICAL
Physical or Chemical Change?
•Melting ice•PHYSICAL
Physical or Chemical Change?
•Cutting wire•PHYSICAL
Physical or Chemical Change?
•Painting fingernails•PHYSICAL
Physical or Chemical Change?
•Cutting fabric•PHYSICAL
Physical or Chemical Change?
•Baking muffins•CHEMICAL
Physical or Chemical Change?
•Shattering glass•PHYSICAL
Physical or Chemical Change?
•Decomposition of old leaves
•CHEMICAL
Physical or Chemical Change?
•Wrinkling a shirt•PHYSICAL
Physical or Chemical Change?
•An old nail rusting•CHEMICAL