Transcript Pure Substances , Compounds , and Mixtures

Pure Substances and
Mixtures
Categorizing Matter
• Everything in the universe is either a
pure substance or a mixture.
Pure Substance =
1) Made of either a single element
or one particular kind of
compound
2) Has a definite composition
1) H2O, NaCl, C, etc.
3) Can’t be broken down into
simpler substances through
physical changes
Two Types of Pure Substances
•
•
Elements
Compounds
Element =
• Consists of only one type
of atom
•
Au, Ag, C, Na, Br, K, H,
etc.
Compound =
• 2 or more different atoms
chemically combined
together
1) Composition is always the
same
2) Cannot be broken down
using physical changes
•
H20, NaCl, CO2, etc.
Mixtures =
• Substances that have been
combined physically (no
chemical reaction)
1) Homogeneous Mixtures =
solutions
•
•
“Homo” = same
Mixture that looks the same
everywhere
– Air, salt water, sugar water
2) Heterogeneous Mixtures =
suspensions
•
•
“Hetero” = different
Looks different throughout
– Mud puddle, blood, salad dressing,
chocolate chip cookie, bird seed
Element, Compound, or
Mixture?
Element, Compound, or
Mixture?
Element, Compound, or
Mixture?
Element, Compound, or
Mixture?
Element, Compound, or
Mixture?
Element, Compound, or
Mixture?
Element, Compound, or
Mixture?
Element, Compound, or
Mixture?
Exam Review and ET:
#9-12
9. A heterogeneous mixture is one that is
not
a. uniform throughout.
b. made of two or more liquids.
c. easily mixed together.
d. edible by humans.
10. Which of the following is a
homogeneous mixture?
a. salad dressing
b. rubbing alcohol
c. gelatin
d. orange juice with pulp
11. A compound differs from a mixture
because it
a. always remains frozen even at high
temperatures.
b. is formed from two cations.
c. always contains the same elements in
the same proportion.
d. can form only in the presence of heat
energy.
12. Each molecule of table sugar,
C12H22O11, contains
a.0 atoms of carbon.
b.6 atoms of carbon.
c. 1 atom of carbon.
d. 12 atoms of carbon.