Transcript Elements, Compounds, and Mixtures

ELEMENTS, COMPOUNDS, AND
MIXTURES
8TH GRADE SCIENCE
8.P.1.1 CLASSIFY MATTER AS ELEMENTS, COMPOUNDS, OR MIXTURES BASED ON
HOW THE ATOMS ARE PACKED TOGETHER IN ARRANGEMENTS.
COMPARING ELEMENTS,
COMPOUNDS, AND MIXTURES
• Creating a foldable:
• Fold a blank sheet of paper in half hamburger style
• Next, fold the half size into thirds
• Carefully cut along the folds of only the top half of folded paper so that
you have 3 flaps, then glue down in your notebook
Elements
Label each flap with the
following information:
Flap 1 Title: Elements
Compounds
Flap 2 Title: Compounds
Flap 3 Title: Mixtures
Leave room under each title
for additional information
Mixtures
HOW DO WE CLASSIFY MATTER?
• What is a pure substance?
• Any substance that cannot be physically broken down into simpler substances
• Includes both elements and compounds
• What is an element? (put information below title of flap)
• A pure substance that is made up of only one kind of atom  H, He, O2
• Organized on the periodic table
• Represented with a chemical symbol
• What is a compound? (put information below title of flap)
• A pure substance made up of two or more elements that have been chemically combined
• Represented using a chemical formula  C6H12O6, NaCl
WHAT ARE MIXTURES?
• (Put information below title of flap)
• The physical combination of 2 or more pure substances
• Mixtures are NOT chemically combined
• Mixtures can be separated by physical means (filtration,
evaporation, distillation)
• Mixtures are divided into two groups
• Homogeneous – a mixture that is evenly distributed
• Heterogeneous – a mixture that is unevenly distributed
ELEMENTS
BACK OF “ELEMENTS” FLAP
• A pure substance
• In an element, all atoms are
identical and share the same
physical and chemical properties
• Elements are organized on the
periodic table
• There are over 100 known elements
INSIDE “ELEMENTS” FLAP
• Elements are represented with a
chemical symbol.
• The symbol is at least one letter; the
first letter is always capitalized
• Example: H (Hydrogen) & He (Helium)
• Some elements are diatomic (2
atoms); they occur in nature in
groups of two
• H2, O2, Br2, Cl2
Compounds
Back of
“Compounds”
Flap
Inside
“Compounds”
Flap
• A pure substance
• A compound is a combination of 2 or more
elements joined by chemical bonds
Represented with a chemical formula 
C6H12O6, NaCl, H2O
• What is the difference between a
molecule and a compound?
Type of Substance Can it have two or
more types of
atoms?
Molecule
Yes
Can it have one
type of atom?
Can it be an
element?
Yes
Yes
Compound
Yes (it must!)
No
No
• All compounds are molecules, but not all molecules are compounds 
O2 is a molecule, but it’s not a compound
MIXTURES
•
•
•
BACK OF “MIXTURES” FLAP
INSIDE “MIXTURES” FLAP
HOMOGENEOUS MIXTURES
HETEROGENEOUS MIXTURES
These mixtures are evenly distributed
and may look like pure substances
because they are completely mixed into
a single phase
Also called solutions – contain a solute
(the substance being dissolved) dissolved
in a solvent (the substance doing the
dissolving)
Examples: salt water, Kool-aid, brass
• These mixtures are not evenly
distributed
• The substances are considered
insoluble because one substance will
not dissolve in the other
• Examples: oil and water, Chex mix,
chicken noodle soup, iced tea
Venn Diagram – Comparing elements, compounds, and mixtures
Place the letter for each description
in its location on the Venn Diagram
A.
B.
C.
D.
E.
F.
G.
H.
I.
J.
K.
Pure substance
Only one type of atom
Two or more types of atoms
Always homogeneous
Can be homogeneous
Matter
Can be two or more phases
There are about 100 different ones
Two elements joined by chemical
bonds
Can be separated by physical
change
Can be broken down by chemical
change
Elements
B, H
A, D
E, F
K, I
Compounds
C
G, J
Mixtures