Physical%20and%20Chemical%20Properties%20and%20Changes

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Physicaland Chemical Properties and Changes
Mrs. StorerChemistry
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Physical versus Chemical Properties
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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?

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What is a property?

• Property a characteristic of a substance that
  can be observed.

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Physical Property
Physical property a property that can be
observed without chemically changing the matter.
These are usually physical descriptions of the
material, but they can also include some
behaviors.

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Physical properties can be used to separate
mixtures!
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Physical Properties
Examples
Color Shape
Size (volume) Texture
Melting point Boiling point
Mass Weight
Luster Specific heat
Solubility Elasticity
Phase Density (more on this later)
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Physical Properties Behaviors
Examples
Malleability the ability to be hammered into a thin sheet Ductility the ability to be stretched into a wire
Magnetic attraction of a magnet to iron Viscosity the resistance of a fluid to flow
Buoyancy ability of a substance to float
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Extensive vs Intensive Properties

• Physical properties can be described as
• Extensive dependent on the amount of the
  substance
• Examples mass, length, volume
• Intensive independent on the amount
• Examples density, scent
• Demo float two pieces of wood of different
  lengths

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Special Physical Properties

• Melting point the temperature at which a
  substance changes from a solid to a liquid at a
  given pressure
• water 0oC
• Boiling point the temperature at which a
  substance changes from a liquid to a gas at a
  given pressure
• water 100oC

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Chemical Properties

• Chemical property describes how a substance
  interacts with other substances.

Examples
Flammabilty Ability to rust
Reactivity Combustability
Acidity Basicity
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FLAMMABILITY A materials ability to BURN in
the presence of OXYGEN
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REACTIVITYHow readily (easily) a substance
combines chemically with other substances.
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Which has higher reactivity? A 14 karat gold
ring or a cheap metal ring from the vending
machine at the grocery store? What is your
evidence?
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Physical and Chemical ChangeMatter can change
in two different ways1. Physical Change2.
Chemical Change
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(1) Physical Change
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. 
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(1) Physical Change

• Signs of physical change include
• Changing the shape or size
• Dissolving
• State change

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Phases of Matter
 
Phase Shape Volume
Solids Definite shape Definite volume
Particles packed together Particles packed together

Liquids Indefinite shape Definite volume
Particles have room to move around Particles have room to move around

Gases Indefinite shape Indefinite volume
Particles far apart Particles far apart
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melting freezingcondensingbreakingcrushingcut
tingbending
Common examples of physical changes are
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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
dont like your haircut!
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Chemical changes, or chemical reactions, are
changes that result in the production of one or
more new substances. 
(2) Chemical Change
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Chemical Change

• Signs of a chemical change
• include
• gas bubbles
• color change - leaves turning colors in the
  fall, rust appearing
• disappearance of color fading fabric
• heat or light

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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 reaction
that produces water and carbon dioxide. 
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Common examples of chemical changesdigestion
respirationphotosynthesis burningdecomposition 
tarnishingrusting
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Light
6CO2 6H2O ? C6H12O6 6O2
Light Energy
CO2 H2O
Chloroplast
Sugars O2
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Chemical Change
Cleaning tarnished silver
Tarnish is silver sulfides that form from sulfur
compounds in the air
?
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Only sure proof that a new substance is produced
is a rapid release of energy heat, light, and
sound
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WEATHERING CHEMICAL OR PHYSICAL CHANGE?
BOTH
Forces of nature reshape Earths surface
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Physical
Large rocks split when water freezes Doesnt
change the rock
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Streams cut through softer rock Canyons
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Chemical
Solid Calcium Carbonate, found in limestone,
doesnt dissolve easily
React with acid (rain)
White Cliffs of Dover
Changes to a new substance (Calcium Hydrogen
Carbonate)
This does dissolve with water
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Caves stalactites and stalagmites
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Law of Conservation of Mass
Amongst all of this change, remember that Mass
cannot be created nor destroyed.
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Lets practice
Number your paper from 1-15 and write if it is a
physical or chemical change
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Physical or Chemical Change?

1. Painting wood
2. Burning paper
3. Digestion of food
4. Sugar dissolving in water
5. Iron turning red when heated
6. Evaporation
7. Pond freezing in winter

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Physical or Chemical Change?

1. Cutting wire
2. Painting fingernails
3. Cutting fabric
4. Baking muffins
5. Shattering glass
6. Decomposition of old leaves
7. Wrinkling of a shirt
8. Old nail rusting

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Physical or Chemical Change?

• Painting Wood
• PHYSICAL

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Physical or Chemical Change?

• Burning Paper
• CHEMICAL

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Physical or Chemical Change?

• Digestion of food
• CHEMICAL

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Physical or Chemical Change?

• Sugar dissolving in water
• PHYSICAL

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Physical or Chemical Change?

• Iron turning red when heated
• PHYSICAL

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Physical or Chemical Change?

• Evaporation
• PHYSICAL

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Physical or Chemical Change?

• A pond freezing in winter
• PHYSICAL

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Physical or Chemical Change?

• Cutting wire
• PHYSICAL

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Physical or Chemical Change?

• Painting fingernails
• PHYSICAL

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Physical or Chemical Change?

• Cutting fabric
• PHYSICAL

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Physical or Chemical Change?

• Baking muffins
• CHEMICAL

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Physical or Chemical Change?

• Shattering glass
• PHYSICAL

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Physical or Chemical Change?

• Decomposition of old leaves
• CHEMICAL

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Physical or Chemical Change?

• Wrinkling a shirt
• PHYSICAL

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Physical or Chemical Change?

• An old nail rusting
• CHEMICAL

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Physical or Chemical Property?
Combustibility CP Density PP
Malleability PP Tendency to corrode CP
Weight PP Volume PP
Failure to react CP Melting point PP
Ductility PP Odor PP
Texture PP Flammability CP
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Physical or Chemical Change?
Digestion of food CC Explosions CC
Getting a haircut PP Lighting a candle CC
Evaporation PC Tarnishing silver CP
Ice cube melting PP Formation of acid rain CP
Crushing rocks PP Dissolving salt in water PP