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04/19/234
Physical Properties
•Can be observed or measured without changing the identity of the matter.
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•Example: You don’t change the identity of an apple to find it’s volume or see that it is red
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Thermal Conductivity: The rate at which a substance transfers thermal energy (heat)
Example: Cup of hot chocolate warms your
hands
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Solubility: The ability of a
substance to dissolve into another substance.
•Example: Lemonade mix dissolves into water
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•Ductility: •The ability of a substance to be pulled into a wire.
Example: Copper Wire is ductile
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• Malleability: • The ability of a substance
to be rolled or pounded into thin sheets.
• Example: Aluminum can be rolled into sheets to make aluminum foil
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• You use physical properties all the time.
• For example, physical properties help determine if your socks are clean (odor) or if you can fit all your books into your backpack (volume).
MetalsSilver/ gray in color (except for Copper
and Gold)Have luster (shiny)Hard, solid (except for Mercury which
is a liquid)Malleable and DuctileGood conductors of electricity and
heat
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Metals can oxidize- react to Oxygen and rust forms
Examples of Metals:
Nickel, Titanium, Tungsten, Tin, Iron
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NonmetalsNot able to conduct electricity or heat
Are not malleable or ductile
Many are gas and a few are solid
Examples: Helium, Oxygen, Chlorine, Neon
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MetalloidsSolid
Located on stair step between metals and nonmetals on periodic table.
Have properties of metals and nonmetals
Semi- conductors04/19/23
15
Density•A physical property, a
measurement
•The mass per unit volume
• Density = mass
volume
D= m
v04/19/23
17
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Practice Problems•Example: What is the density of an object with a mass of 20g and with a volume of 10 mL?
•D= ?•1. Write the equation
D= m v
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•Example 2: What is the density of an object with mass of 35 g and with volume is 7 cm3?
•Write the steps and solve yourself.
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Chemical Property
Describes matter based on its ability to change into new
matter with different properties.
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Just so you know….
Reactivity the ability of 2 or
more substances to combine & form a
new substance
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Reactivity with Oxygen- When metal is
exposed to oxygen and
changes.Ex: Rusty nail,Statue of Liberty
Non-reactivity with oxygen: Substances or
objects that will not rust.
Ex: The bumper on a car
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What’s the difference?
•Physical Properties- Can be measured or observed and do NOT change what something is made of.
Chemical Properties:Describes how something will react.DOES change the chemical nature of matter
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Physical Change•A change that affects one or more physical properties of a substance.
Example: Breaking a piece of chalk in two pieces.
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Examples of Physical Changes
•Freezing water for ice cubes
•Sanding a piece of wood
•Cutting your hair
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Chemical Change• Two or more substances are
changed into a new substance
•Not the same as Chemical Properties
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Remember……•Chem. Props just describe the ability of a substance to go through a chemical change
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Signs of a Chemical Change
•Changes in color•Heat is produced •Fizzing and Foaming•Sound is produced•Gas is produced•Light is produced•Change in smell
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What happens during a chemical change?
•When you bake a cake, you combine eggs, flour, sugar, oil, and other ingredients.
•Each ingredient has its own set of properties
•But if you mix all the ingredients together, you get something completely different.
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•The heat of the oven and the interaction of the cake ingredients cause a chemical change.
Physical Change: A change in appearance only; DOES NOT CHANGE the identity of the matter
Examples:Size change
Shape changeState change ( solid to liquid)
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Chemical Change: Produces new matter with different properties. The identity of the matter DOES change
Examples:Color Change
Heat produced or removedFizzing & Foaming
Smell ChangeLight/ Sound Produced
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EndothermicEnergy is gained by a substance
- Think “endo”= enterExample:
Ice melting into liquid water. The molecules gain energy and speed up
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ExothermicEnergy is removed from, or
taken out of, a substance. Can give off heat
Think “exo” = exitExample:
Water freezing to a solid. The molecules lose energy and
slow down.04/19/23
46
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Solid•definite shape •definite volume•Molecules are very close together
•Molecules vibrate in place
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Liquid•No definite shape; takes the shape of its container
• Ex: When you pour water from a beaker into a graduated cylinder does it stay in the shape of the beaker? Nope!
•definite volume
•Molecules completely break away from each other.
•There is empty space between the molecules.
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