October 19, 2009
• Update your planner.
• Hand in Combinations of Atoms.
• Open your book to page 44.
• Set up your Cornell Notes.
• Today’s Theme: How can we
classify matter?
PROPERTIES OF MATTER
Describing Matter
Physical Properties
• A property of matter that can be
observed or measured without
changing the identity of the
matter.
Physical Properties
• Physical properties identify matter.
• Examples include but are not limited to:
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Density
States of Matter (Solid, Liquid, Gas, Plasma)
Solubility
Freezing point
Boiling point
Melting point
Color
Smell
Thermal Conductivity
Attraction or repulsion to magnets
Malleability
Ductility
Opacity
Viscosity
2.1
Identifying Substances
Physical Properties
• Density is a measure of how much mass is
contained in a given unit volume .
• A measure of how tightly that ‘stuff’ is packed
together
• A ratio of mass to volume
• Density equals mass divided by volume.
• Density = mass ÷ volume or
Physical Property
• Malleability - The ability to be pounded into thin
sheets.
• Example: Aluminum can be rolled or pounded
into sheets to make foil.
• Ductility - The ability to be drawn or pulled into a
wire
• Example: Copper in wiring – soldering wires or
joints
Physical Property
• Thermal Conductivity - The
ability to transfer thermal energy
from one area to another.
• Examples:
• Plastic foam is a poor conductor, so a
hot drink won’t burn your hand.
• The inside of the toaster (hot coils) are
good at transferring heat.
Physical Property
• Solubility - The ability to dissolve in
another substance.
• Example:
• Sugar or salt dissolve easily in water
but sand dissolves slowly
• Three ways to increase solubility
• Heat or make warmer
• Grind or smash
• Stir or mix
5 States of Matter
Bose-Einstein
Condensate
Solid
Liquid
Gas
Plasma
Physical Property
• State of Matter - The physical form in
which a substance exists:
• Bose Einstein Condensate - super-unexcited and
super-cold atoms.
• Solid – matter has a definite shape and volume
• Liquid – matter takes the shape of its container
and has a definite volume
• Gas – matter changes in both shape and volume
• Plasma – positively charged atoms (ions) and
free electrons.
Bose-Einstein
Condensate
• This state of matter was the only one
created while you were alive.
• In 1995, two scientists, Cornell and
Weiman, finally created this new state of
matter.
• Two other scientists, Satyendra Bose and
Albert Einstein, had predicted it in the
1920. They didn't have the equipment and
facilities to make it happen in the 20s. Now
we do.
• If plasmas are super hot and super excited
atoms, the atoms in a Bose-Einstein
condensate (BEC) are total opposites
States of Matter
What are the atoms doing in each state?
Physical Change
• A change that affects one or more
physical properties of a
substance.
• Does form new substances.
• Can often be undone
• Example melted ice can be placed
back in refrigerator.
States of Matter
Lutgens and Tarbuck: The Atmosphere
2.1
Physical Changes
•Physical changes can be classified
as reversible or irreversible.
•All physical changes that involve a
change from one state to another
are reversible.
•Cutting hair, filing nails, and
cracking an egg are examples of
irreversible physical changes.
Chemical Property
• A property of matter that describes a substance based on its
ability to change into a new substance with different
properties.
• Examples:
• 1 pH - The pH scale measures how acidic or basic a substance
is.
• a measure of the relative amount of free hydrogen (H+) and
hydroxyl ions (OH-).
• The pH of water determines the
− solubility (amount that can be dissolved in the water)
− biological availability of nutrients (amount that can be
utilized by aquatic life).
• 2. Combustibility - when wood burns
• 3. Flammability - when fireworks explode
• 4. Reactivity - when iron Oxidizes (rust)
pH scale
Physical Changes
2.1
• During a physical
change, some properties
of a material change,
but the composition of
the material does not
change.
• As gallium melts in a
person’s hand, the shape
of the sample changes,
but the composition of
the material does not
change.
Chemical Change
• A change that occurs when one or more
substances are changed into entirely new
substances with different properties.
• Can’t change back under normal conditions
(example – vinegar and baking soda).
• Common Examples:
• Reactivity – Oxidation (rust) on a bicycle
• pH (Acid / Base) – Effervescent tablets (Alka Seltzer) and
your stomach
• Flammability – Burnt wood
• Combustibility - Fireworks