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Target 2.3
Differentiate between pure substances
and mixtures
Elements, Compounds and Mixtures
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Target 2.4
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You need to do this:
Identify different types of mixtures
Identify pure substances
Identify homogeneous mixtures
Identify heterogeneous mixtures
Identify solvents & solutes
Identify suspensions & solutions
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Pure Substances - Elemental
Matter
Elemental
Matter Classified
Composed of identical atoms
EX: copper wire, aluminum foil
Pure = only a single element
○ Gold (Au), Silver (Ag)
Impure = Two or more compounds together
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Pure Substances - Compounds
Pure Substances - Elemental
Copper is Copper
For example+
It is an element – it does
not break down any further
than that
Check the chemical
formula: Cu
That makes it a pure
elemental substance
Two different compounds,
each has a definite composition.
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Pure Substances - Compounds
Pure Substances - Compounds
Halite (table salt) is
a compound
Compound:
A molecule composed of 2 or more different
elements
Check the chemical
formula: NaCl
NOT elementally
pure
But, if there is
nothing but salt,
then it is pure salt
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Pure Substances - Compounds
Pure Substances - Compounds
Many minerals are
compounds
All are pure
substances
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Fluorite (CaF2) is a mineral
compound that is a pure
substance
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Pure Substances - Elemental
Pure Substances - Elemental
Gold (Au) is an element
(pure substance) and a
mineral
So is silver (Ag)
Copper (Cu) is a pure
substance that is an
element that is a mineral
So is platinum (Pt)
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Pure Substances - Molecules
Pure Substances - Molecules
A molecule is a compound in which two
or more elements are bonded together
Nitrogen gas is N2
Oxygen gas is O2
They CAN be the same element)
Hydrogen gas is H2
These are all molecules and not
compounds because each is composed
of a single element
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Pure Substances - Molecules
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Compound or Molecule?
Acetaminophen
Water (H2O), carbon dioxide (CO2) and
methane (CH4) are compounds because
each is made from more than one
different element
C8H9NO2
Caffeine
C8H10N4O2
Ensulizole
C13H10N2O3S
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Water
H2O
Calcium Carbonate
CaCo3
Ozone
O3
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Pure or Impure?
Acetaminophen
Mixtures
Water
C8H9NO2
Caffeine
Calcium Carbonate
C8H10N4O2
Ensulizole
C13H10N2O3S
A mixture is combination of two or
more substances in which each
substance retains its properties
H2O
Remember, a compound is a “mixture” of
two or more elements, BUT
CaCO3
○ The properties of the elements change after
Ozone
combining
O3
NaCl
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Mixtures
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Mixtures
If elements and compounds are just
hangin’ out together, then they are a
mixture
BUT if they come together to form a
brand new thing, then they become a
pure substance)
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Mixtures
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Heterogeneous or Homogeneous?
Most stuff is a mixture of some kind
There are two types of mixtures:
Homogeneous & Heterogeneous
How can you tell them apart?
Homogeneous Mixtures:
Different parts cannot be seen individually
Heterogeneous Mixtures:
Different parts can be seen individually
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Heterogeneous or Homogeneous?
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Suspensions: Not Just for 8th Graders…
About 55% of blood
is blood plasma
The blood's liquid
medium
○ Which is actually
straw-yellow in color
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Suspensions: Not Just for 8th Graders…
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Suspensions: Not Just for 8th Graders…
The rest of blood is
composed of several
kinds of cells
Suspended solids
can settle (sink) to
the bottom of the
medium
Red blood cells, white
blood cells and
platelets
○ The “Solids”
suspended (floating) in
the liquid medium
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Suspensions: Not Just for 8th Graders…
Suspensions: Not Just for 8th Graders…
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Heterogeneous or
Homogeneous?
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Homogenous Mixtures
Earth’s Atmosphere
is a mixture of
elements and
compounds
Nitrogen 78%
Oxygen
21%
Argon
0.9%
Water Vapor
0 - 4% (variable)
Carbon Dioxide
0.034% (variable)
Suspension? Homogeneous? Heterogeneous?
Pure? Impure?
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Mixtures
H2O
ClNa+
Mg2+
SO42
Ca2+
K+
C
BrBT
Sr2+
F-
Mixtures
Classified
Solution:
○ All parts in the
mixture are in the
same matter phase
Air, Salt Water
Suspension:
○ All parts are not in
the same matter
phase
Suspension? Homogeneous?
Heterogeneous? Pure? Impure?
Milk, Fog, blood
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Matter Flowchart
MATTER
yes
MIXTURE
no
Can you see pieces
of it?
Homogeneous
Mixture
(solution)
PURE SUBSTANCE
yes yes
Heterogeneous
Mixture
Colloids
no
Can it be physically
separated?
Can it be chemically
decomposed?
Compound
no
Element
Suspensions
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