Do Now …
Date: September 19, 2016
Objective: Complete separation of complex mixture
and record observations.
Read:
During the lab:
 Place separated substances on a paper towel.
 No solids go in the sink.
 Smaller quantities of liquids evaporate faster!
Monday, September 19, 2016
Today:
Lab: Separating a Mixture
Work on Lab Write-Ups
Unit Test Friday, Lab Due Friday
During the lab …
Record your observations!
• What did the substances look like?
• Where they pure?
• Difficulties you experienced.
You can collect digital images during
the lab (as well as video).
NB
Nota Bene
Note Well
The LAST day to hand in missing
labs is this Friday.
Do Now …
Date: September 20, 2016
Objective: Observe and record data on the Tyndall
Effect for solutions, colloids, and suspensions.
Copy the table below:
Mixture
Solution
(e.g. salt water)
Colloid
(water +
toothpaste)
Suspension
(muddy water)
Particle
Size
Small
Medium
Large
Light …
Tyndall Effect?
Passes
through
Spreads
out
No
Spreads
out
Yes
Yes
Notes
Doesn’t
separate
Doesn’t
separate
Separates after
a while
Tuesday, September 20, 2016
Today:
W-Up, Tyndall Effect Demo,
Practice Test
HW: Google Form (see Breslyn.org)
Study for Test on Friday
Tyndall Effect
Solutions, Suspensions, & Colloids
Types of mixtures.
We can classify them by the size of
particle in the mixture.
Tyndall Effect
Tyndall Effect – colloids and suspensions
scatter light in all directions.
Tyndall Effect
Image from www.silver-lightning.com/ tyndall/
Tyndall Effect
Image from www.silver-lightning.com/ tyndall/
Tyndall Effect
Image from www.silver-lightning.com/ tyndall/
Tyndall Effect
This effect is also seen when
headlights shine into a fog and when
sunlight shines through clouds.
Tyndall Effect
A short-wavelength wave is stopped or reflected
A long-wavelength wave is not affected
Image from http://www.madsci.org/posts/archives/nov99/943908453.Ch.r.html
Solutions, Suspensions, & Colloids
Solutions – smallest particles (less than 1 nm).
Particles do not settle.
Colloids – smaller particles (greater than
100 nm) than suspensions (e.g. gelatin desserts,
paint). -- Exhibits Tyndall Effect
Suspensions – mixtures where the particles
(1 to 1000 nm) slowly settle (e.g. clay in water).
-- Exhibits Tyndall Effect
Elements & Compounds
Elements - single atoms – for
example Fe, Cl, Mg, … .
Compounds – combination of
elements – H2O, NaCl, H2SO4
Elements & Compounds
KI
Compound
HCl
Compound
Ce
Element
U
Element
MnO2
Compound
Pure Substances
Pure substances:
• have a constant composition
• cannot be separated or broken
down by ordinary physical means.
Is water a pure substance?
Mixtures
• A combination of two or more
different substances.
• Can be separated by physical means.
Mixtures and Compounds
What is the difference between a
mixture and a compound?
Salt
Compound (NaCl)
Distilled (Pure) Water
Gatorade
Salt Water
Compound (H2O)
Mixture (H2O, electrolytes, sugar, …)
Mixture (NaCl and H2O)
Homogenous Mixture
• Same composition throughout.
• Particles equally distributed.
• Example: salt dissolved in water.
Also called a solution.
Heterogeneous Mixture
• Varying composition in sample.
• Example: a salad.
Physical Properties
Salt -Sand -Paper -Gravel -Iron Filings -Styrofoam --
Wednesday-September 21, 2016
Date: September 19, 2016
Objective: Complete formal write-up of separation of
complex mixture and record observations.
Read:
• Follow the rubric! This is how you will be assessed.
• Each person turns in their own type-written lab.
• Some part of your lab may be similar but the write-up
should be your own work!
• For the conclusion – see Breslyn.org for a possible
template.
Thursday-September 22, 2016
Today:
Review Practice Test, Study / Alloy Lab
HW: Finish Practice Test
Work on Final Draft of Separation Lab
Alloys
Alloys are a mixture of two or more
metals.
The mixture has different properties
than the individual metals. They
could be stonger, conduct electricity
better, absorb heat faster, … .
Chemical or Physical Change?
Chemical changes
result in the
formation of a
new compound.
Evidence of a Chem. Change
Changes in heat and light.
Color changes.
Formation of a precipitate.
Formation of a gas (sometimes bubbles).
Remember: the change is difficult to reverse.
Warm-Up: Determine the Density
Mass of substance:
48 grams
Volume of substance: 96 mL
What is the density?
When placed in water, will it float?
Will it float?
A substance was determined to have a mass of
3.2 grams. It’s volume was 3.0 mL.
When placed in water, will it float?
Do Now …
Date: September 23, 2016
Objective: complete unit test.
Use the time before class to quickly review for
the test. Look especially at any information
you don’t know very well. When you get the
test, look it over and try answer questions
about this information first.
Reminder: Final draft of Separation Lab due next Tuesday!
Friday, September 23, 2016
Today:
Unit Test
Note: Final typed separation lab is due on Tuesday.
Old Content
Do Now …
Date: September 18, 2014
Objective: Make an alloy (brass) and describe it’s
composition.
Copy: An alloy is a mixture of two or more metals
(and sometimes non-metals).
Alloys have useful properties that differ from the
original metals.
Examples: brass (Zn + Cu),
stainless steel (Fe + Cr + Ni)
Thursday, September 24, 2015
Today:
Lab: Alloys
HW:
Study for Unit Test Tomorrow
W-Up
Tyndall Effect
Alloys BCR
1. Use the terms mixture, physical property,
physical change, element, atom,
heterogeneous, homogenous, and melting
point to describe today’s lab.
2. How is an alloy different than a compound?
3. We say that an alloy is a mixture of two or
more metals. Draw a diagram of how the atoms
of zinc and copper would appear if you could see
them in a pre-1982 penny and your “gold” penny.
---------------------------W
Other Periodic Tables
http://chemlab.pc.maricopa.edu/periodic/spiraltable.html
Other Periodic Tables
http://chemlab.pc.maricopa.edu/periodic/spiraltable.html
Na(s) in H2O(l)
http://www.theodoregray.com/Periodi
cTable/Stories/011.2/Videos/SodiumR
esearch02.html
Do Now …
Date: September 20, 201Objective: Develop strategy and prepare for unit
test Friday.
Log in and go to www.Breslyn.org.
On the paper provided copy and answer:
• What is your goal for the unit test?
• What do you need to study most?
What do you need to study?
• Know what is going to be tested.
• Focus on areas where you are weak.
• Study in several sessions.
Today…
1. Take the practice test (link on Breslyn.org.)
2. Study the section(s) you did poorly on.
3. Retake the practice test.
Show me your score.
Exit Ticket
Two topics you still need to study:
1.
2.