Bellwork: Monday 4/23/2012
• Classify the following
as either a chemical
change or a physical
change:
– Boiling Physical Change
– Burning Chemical Change
• On a molecular level,
how would you
describe the
difference between
boiling something,
and burning
something?
Different Phase- Still
same bonds; farther
apart, moving faster
NEW substance- Bonds
broken, reformed
Think about it…
• A garden salad is made
up of lettuce, tomatoes,
cucumbers, ham, egg,
bacon bits, and croutons.
• Compare this to
dissolving sugar into unsweet tea.
– Hint: think about each
of them as different
things being mixed
together—what is the
end result??
• The salad is not a uniform
mixture (one bite is different
from the next) – the salad is
a heterogeneous mixture
• The tea is a uniform mixture
– once dissolved, the sugar is
spread out evenly in the tea
so one sip tastes like another
– the tea is a homogeneous
mixture
Packet 12, Page 1- Mixtures & Solutions
• Compound- two or more substances chemically
combined
– Only separated by chemical means/reactions
• Examples of compounds:
• Salt (NaCl) – Sodium & chlorine combined chemically
• Water (H2O) – Hydrogen & oxygen combined chemically
• Carbon Dioxide (CO2) – Carbon & oxygen combined chemically
• Mixture- two or more substances mixed together;
NOT chemically combined
– Separated by physical means
• Examples of mixtures:
– Bowl of cereal – mixture of cereal and milk
– Trail mix- mixture of various nuts, fruit, candy
Take a Guess!
Mixture or
Compound?
•
•
•
•
•
•
•
•
Air – mixture of gases
Soda pop – mixture of soda syrup, water, and CO2 gas
Fog – mixture of water and air
Table salt – compound of Sodium and Chlorine: NaCl
Kool-Aid – mixture of water, sugar, and flavor crystals
Water – compound of Hydrogen and Oxygen: H2O
Salt water – mixture of salt and water
Carbon monoxide – compound of Carbon and Oxygen: CO
6.19- TSW USE EVIDENCE TO COMPARE
AND CONTRAST HOMOGENEOUS AND
HETEROGENEOUS MIXTURES.
• Heterogeneous mixture- a
mixture in which the properties
are not uniform (ex. beef stew,
garden salad)
– “Uniform” means the same
throughout
• Suspension- *solid is not
dissolved* Very fine particles of
solid mixed with a liquid; often
looks cloudy; eventually solid
settles to the bottom
• Sediment- *solid is not dissolved
and settles to the bottom*
• Homogeneous mixture- a
mixture in which the
properties are uniform (ex.
sweetened tea)
• Solution- *solid is dissolved*
mixture in which one
substance is dissolved in
another; has two parts:
–Solute- is dissolved (s, l, g)
–Solvent- does the
dissolving (s, l, g—usually
liquid)
• *The solute is present in a
smaller amount than the
solvent*
• Solubility- How
well a solute will
dissolve in a
solvent
–Insoluble- does
not dissolve in
water
–Soluble- does
dissolve in
water
6.21- TSW IDENTIFY THE SOLUTE AND
SOLVENT IN A SOLUTION.
Solution
Solute
Solvent
Lemonade
Sugar (s) and Lemon
Juice (l); Lemonade
powder (s)
Water (l)
Soda pop
Ocean
water
Water (l) &
CO2 – (g)
carbonation/bubbles Syrup (l)
Salt (s)
Water (l)
(s) Means it is a SOLID; (l) LIQUID; (g) GAS
Matter: Pure Substances vs. Mixtures
Packet 12, Page 2
Matter
Solid, liquid, gas
Mixture
Pure Substance
Variable
Composition
Constant Composition; Can
write chemical formula,
homogeneous
Element
Compound
One type of
atom
Two or more different
types of atoms
chemically bonded
Homogeneous
solutions
Heterogeneous
Colloids and
suspensions
In-Class Work: Page 2- Classify Substance vs. Mixture
Type of Matter
Chlorine
Water
Substance- Element or
Compound?
Element
Mixture- Heterogeneous
or Homogeneous?
Compound
Soil
Heterogeneous
Sugar water
Homogeneous
Oxygen
Carbon dioxide
Element
Compound
Rocky road ice cream
Heterogeneous
Pure air
Homogeneous
Silver
Ethyl alcohol (C2H5OH)
Aluminum
Table salt (NaCl)
Sugar
Element
Compound
Element
Compound
Compound
Seawater
Homogeneous
Chocolate chip cookie dough
Heterogeneous
Homogeneous
Vanilla ice cream
Page 5- Separating Mixtures Using Physical Methods:
6.20- TSW SEPARATE MIXTURES USING THE FOLLOWING PHYSICAL
MEANS: FILTERING, MAGNETISM, DISSOLVING, AND EVAPORATION.
1. Filtration- separates a solid (or
suspension) from a liquid
– Example: separate dirt from some
salty water
– How it works: The liquid (and anything
dissolved in the liquid) passes through
holes in the filter paper. The solid
particles are too big and get stuck.
2. Magnetism- separates objects with
magnetic properties, from non-magnetic
objects
– Example: separate iron from sand
– How it works: The magnet sticks to
the iron, not the sand.
3. Dissolving- causes solid matter to
pass into a liquid solution;
“disappears”
– Example: the dissolving of salt
in water
– How it works: Soluble solids will
dissolve, while insoluble solids
will not
4. Evaporation- separates a dissolved
SOLUTE from a SOLUTION
– Example: obtain some pure salt
from salty water
– How it works: When salty water
is warmed the water evaporates
leaving behind crystals of salt.
5. Paper Chromatography- separates the different
colors in dyes
– Example: separate the different colored dyes in
ink pens
– How it works: Place a dot of the dye to separate,
on chromatography paper, and then dip it into a
solvent. As the solvent soaks up through the
paper it carries the dye with it. The more soluble
dyes move further up than the less soluble ones,
hence separating from each other.
In-Class Work: Page 4
• Circle/write correct answers
• Whatever is not finished is homework!
Bellwork: Tuesday 4/24/2012
• Choose one of the five separation techniques we
have studied so far and describe how they can be
used to separate a mixture, and what they
separate.
1.
2.
3.
4.
5.
Evaporation – how / what
Magnetism – how / what
Filtration – how / what
Dissolving – how / what
Chromatography – how / what
Separating Mixtures Lab- Page 5
• Objective: Students will design, conduct, and
justify an experimental design in which they
combine sand, iron filings, gravel, and salt, and
then use physical means to separate the
mixture.
• Data Table
• Procedures
• Conclusion Questions
• We will be working on this lab for one day. Your
mixture should be completely separated by the
end of today.
Separating Mixtures Lab Procedures - Page 5
• Part 1 Procedure:
– Measure and record the “original mass” of the sand, iron
fillings, gravel, and salt in the data table on pg. 6.
– Combine the sand, iron fillings, gravel, and salt in a beaker;
stir until the substances are a complete jumble!
• Challenge:
– Along with your partners, you must now find a way to
separate the jumble that you have created in your beaker
back into the original substances: sand, iron fillings, gravel,
and salt.
– You may only use the tools you have been given!
– Use Part 2 Procedure on pg. 6 to complete the challenge!
– We don’t have a hot plate or blow dryer so MEASURE THE
MASS OF WATER IF YOU USE IT!!
Separating Mixtures Review
• Filtration- separate a solid or suspension from a
liquid
– separating SAND from water
• Magnetism- separate magnetic objects from nonmagnetic objects
– separating iron from salt
• Dissolving- causes solid matter to pass into a liquid
solution; “disappears”
• Evaporation- used to obtain the solute from a
solution
– obtaining SALT from salty water
• Chromatography- used to separate out one color
from a mixture of colors
– separating out the colors in black ink
Bellwork: Thursday 4/26/12
Answer the following questions on your bellwork.
1. In the lab we did yesterday, what separation
techniques worked for you and which ones
did not?
2. Write the order of separation that you found
to be the best.
7. You should
now be left
with separate
piles of salt
and sand!!
1. Filter the
large gravel
from the
sand, salt, iron
mixture.
2. Add water
to the salt
and sand
mixture.
3. Shake well
until the salt
dissolves. The
sand does not
dissolve.
6. You can dry the
sand by carefully
heating the wet
filter paper.
5. Evaporation: Put
the salt solution in the
evaporating basin and
heat with the Bunsen
burner. The water is
evaporated. White
salt crystals will be left
behind.
4. Filtration: Use the
filter paper and the
funnel to filter into
the beaker. The salt
solution passes
through the paper.
The sand remains
behind on the paper.