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FROM BED BUGS TO BIG BUGS
(actually both terms are incorrect)
Kyle’s Girlfriend’s
Hands
http://www.emedicinehealth.com/slideshow_black_widow_brown_recluse_spiders/
article_em.htm
Physical Properties
Knowledge of physical properties allow substances to be
observed and tested without changing the nature of the
substance (chemical composition)
Example: melting ice and boiling water still leaves you with H2O
Also salt and water are easily mixed and separated and the salt
and water still retain their physical characteristics.
Alloys (see handout) and solutions (salt water; air)
Other physical mixtures from the lab….
Physical mixtures are characteristically
non-uniform
Chemical Properties
These properties require the substance to “react” or be
inherently altered so that it is different after the change.
Consider the “Observation Lab” reactions
All required the combination of different substances such
that physical properties after the change were very different
than those before the change.
Chemical mixtures (compounds) are always uniform
Mixture Separation Lab
The mysterious mixture was separated by taking advantage of
the physical properties of the components of the mixture.
Iron - magnetic
Iodine – sublimed and deposited on the cold surface
Sand – did not dissolve in water (insoluble) and particles were
large enough to be trapped by the filter paper
Salts – were all soluble and passed through the filter paper and
were collected by rapid evaporation.
Based on your collected masses, calculate the
percent composition of your mixture.
Magnetic material:
Sublimed material:
Filtered material:
Dissolved material:
Hint: divide your individual masses by the original
mass of your mixture and multiply by 100!
You’re welcome!
Mixture Separation Lab Analysis
Compare your data to the data of classmates
and the “true” values. What do you think
about the data? Is it reliable (can we be
confident that the data can be trusted?)
Explain the differences by identifying
possible errors (human error is not allowed –
be more specific) as you carried out the lab.
Identify the components of the mixture and
the properties used to separate the mixture.
9) Holding the silver penny on the edges with tongs, place it in
the hottest part of a burner flame. Pass it slowly through the
flame.
10) When the color changes again, plunge the penny into a
beaker of water. Metals are hot.
11) Make more coins.
12) Clean up without sin (be impeccable).
Questions
1. Did you make gold? How could you prove it?
2. What element gives the penny its silver color?
3. What temperature does zinc melt? Look it up, lazy bums.
4. What is an alloy?
5. What is an alloy of copper and zinc? Copper and tin?
6. Why are alloys helpful/useful?
7. Draw a picture of what the particles of zinc did with the
particles of copper.
Matter Classification Assessment Evaluation
Honors Chemistry
You will complete assessments prepared by your classmates.
Please evaluate it based on the following criteria (1-4 scale
with 4 being most like and 1 being least like)
Visually pleasing appearance (easy to read and understand)
Challenging (it made you think)
Length (it was great, not too short not too long)
Accuracy (it effectively tested my level of knowledge of the
content)
Reliability (as an assessment tool, students with a similar
understanding would get a similar score)
Enjoyment
Other complements and criticisms:
Mixture Practice Spark
• Complete the worksheet with your lab
group, you will turn in whatever you have
completed.
• Use the flowchart if you need it. It
distinguishes matter by particle size and
how materials are combined.
DOES IT LOOK LIKE ONE
THING?
Is there only one
ingredient in the
composition?
Is it made
not onofthe
more
periodic
than
table?
one
element?
Matter Classification based on particle size!
primary questions
• Does it look like one thing?
• Yes?
• Homogeneous - from the same/one origin
(homo – genesis)
– Mixtures (solutions and alloys) and Pure Substances
– No?
• Heterogeneous - from different/multiple origins (hetero –
genesis)
– Mixture (suspensions and colloids)
Matter Primary Question:
Does it look like one thing?
Yes
Homogeneous
No
Heterogeneous (mixture)
Homogeneous Question
Is it made of one ingredient?
No
Solution (mixture)
Yes
Pure Substance
Heterogeneous Question
Does it always look like more than one thing? Are the
components easily observed?
Yes
suspensions
No
Colloids
(From the Greek word for glue)
Dispersing Medium
Gas
Liquid
Solid
shaving cream,
whipped cream
foam rubber,
sponge,
pumice
Liquid
fogs, clouds,
mayonnaise,
aerosol can spray milk, face cream
jelly, cheese,
butter
Solid
smoke,
car exhaust,
airborne viruses
Gas
Gold in water,
milk of
magnesia,
river silt
alloys of metals
(steel, brass)
Colloidal Dispersions
Dispersing Medium
Gas
Gas
Liquid
Solid
Foam
Foam
Liquid
Aerosol
Emulsion
Gel
Solid
Aerosol
Sol
Solid Sol
Dispersed particles 1100 nanometers in
size
Tyndall effect – helps distinguish between colloids and
solutions (mixtures distinguished by the size of particles).
Gold in water
B
This liquid has
particles that are big
enough to disperse
light.
• Positive Tyndall
Effect
• Colloid
Pure Substance Question:
Is it unable to be separated into simpler forms of matter?
Yes
Elements
(Is it on the periodic table)
No Compounds
Solution Question:
Is it made of metal?
Alloy
(see handout)
Yes
No
Element Question:
Is it conductive, shiny, malleable, ductile?
Yes
metal
No
(periodic table)
nonmetal
Kind of? Metalloid/Semimetal
Compound Question:
After mixing with water, is it conductive?
Yes
Electrolyte
(ionic and soluble)
No
Nonelectrolyte (covalent
or insoluble)
Electrolyte Question:
Is the pH of the solution less than 7?
Yes Acids pH < 7
No
Bases pH >7 or Neutral pH = 7
pH = 7
Water and Salts
Nonelectrolyte Question:
Is it a carbon based compound?
Yes Organic
No
No Inorganic
There are entire years of college
chemistry curricula devoted just to
these two categories of chemical
compounds
Alchemy 101
Chromatography
Spark
Measure
the line on your
measurement packet
(in cm). Do not just
copy the measure of
your neighbor
http://micro.magnet.fsu.edu/primer/java/scienceopticsu/powersof10/
ALL Measurements in Science
use the
Metric System The International System
NOT the
English System
Systems of Measurement
The U.S.
English System
The rest of the World
Metric System The International System
SI Base Units
Mass
Length
Time
Energy
Temperature
Amount of substance
kilogram
meter
second
Joule
Celsius o
mole
Derived Units
Derived units involve
multiple base units.
Derived Units
Area
2
= length
Derived Units
Area
2
= length
3
Volume = length
Derived Units
Area
2
= length
3
Volume = length
Density = mass / volume
SI Prefixes
SI Prefixes
mega
1 000 000
SI Prefixes
mega
kilo
1 000 000
1 000
SI Prefixes
mega
kilo
centi
1 000 000
1 000
0.01
SI Prefixes
mega
kilo
centi
milli
1 000 000
1 000
0.01
0.001
1 ml = 1
3
cm
Say, "cubic centimeters"
NOT centimeters cubed
Important Derived Units
1 liter = 1 cubic decimeter, dm3
Important Derived Units
1 liter = 1 cubic decimeter, dm3
1 milliliter = 1 cubic centimeter, cm3
Important Derived Units
1 liter = 1 cubic decimeter, dm3
1 milliliter = 1 cubic centimeter, cm3
Density of H2O = 1 gram / cm3
"cubic centimeters" NOT centimeters cubed
kilo = 1000
hecto = 100
deca = 10
the base = 1
deci = 0.1
centi = 0.01
milli = 0.001
When converting from a
big prefix to a small prefix...
kilo
hecto deka
1
deci
centi
milli
multiply by 10 with each step.
When converting from a
big prefix to a small prefix...
X10
kilo
hecto deka
1
deci
centi
1 dekameter = 10 meters
milli
When converting from a
big prefix to a small prefix...
X10
kilo
hecto deka
1
deci
centi
1 dekameter = 10 meters
1 dekameter = ? centimeters
milli
When converting from a
big prefix to a small prefix...
X10
kilo
hecto deka
1
deci
centi
milli
1 dekameter = 10 meters
1 dekameter = 1000 centimeters
When converting from a
small prefix to a big prefix...
/10
kilo
hecto deka
1
deci
centi
divide by 10 with each step.
milli
When converting from a
small prefix to a big prefix...
/10
kilo
hecto deka
1
deci
centi
1 centimeter = .01 meters
milli
When converting from a
small prefix to a big prefix...
/10
kilo
hecto deka
1
deci
centi
1 centimeter = .01 meters
1 centimeter = ? kilometers
milli
When converting from a
small prefix to a big prefix...
/10
kilo
hecto deka
1
deci
centi
milli
1 centimeter = .01 meters
1 centimeter = .00001 kilometers
cm
All numbers in chemistry
are measurements so they MUST have units.
oC
g
3
cm
SPARK
Use your
measurement packet
This dust mite is
about 450
micrometers long.
Yer bed is sooo cozy.
We really ‘preciate yer
hospeetality!
How many mites could fit lengthwise on a 2.5
meter mattress?
SPARK II
The average
mattress increases
it’s mass nearly
4000g in 5 years.*
Sorry fer the mess, I know my
youmite
sneeze,
but
How many pounds of dead poop
skin, makes
mite and
droppings
dang per
yer skin
is (2.2
delicious!
is added to your sleep cushion
year?
lb = 1kg)
*debatable
After 2 years, 10% of your pillow’s mass can be accounted
for by dead mites and their droppings.* How many
milligrams of a 0.85 kg pillow is dust-mite?
Metric Prefixes
• You need to know them…
• Their size (magnitude) and also their power of 10
– Examples: milli = 1000th or 10-3 or 3 decimal places
kilo = 1000 or 103 or 3 decimal places
And how to change from one prefix to the other.
Example: milli to kilo to
centi to
mega
42 mg =
0.000042 kg =
4.2 cg =
0.000000042 Mg
4.2 x 101 mg = 4.2 x 10-5 kg = 4.2 x 100 cg = 4.2 x 10-8 Mg
Remember: Its a question of scale
1 X 106 meters - 1 megameter
1 000 000
Its a question of scale
1 X 105 meters - 100 kilometers
100 000
Its a question of scale
1 X 104 meters - 10 kilometers
10 000
Its a question of scale
1 X 103 meters - 1 kilometer
1 000
Its a question of scale
1 X 102 meters - 100 meters
100
Its a question of scale
1 X 101 meters - 10 meters
10
Its a question of scale
1 X 100 meters - 1 meter
1
Its a question of scale
1 X 10-1 meters - 0.1 meter - 10 cm
0.1
Its a question of scale
1 X 10-2 meters - 1 centimeter
0.01
Its a question of scale
1 X 10-3 meters - 1 millimeter
0.001
Its a question of scale
1 X 10-4 meters - 100 micrometers
0.000 1
Its a question of scale
1 X 10-5 meters - 10 micrometers
0.000 01
Its a question of scale
1 X 10-6 meters - 1 micrometer
0.000 001
Uncertainty in Measurement?
• Science may claim to be a search for “truth”,
but never claims to be 100% confident that it
knows the “facts”.
• Why not?
• Where have scientists been mistaken?
• Is it a question of scale? How big or small
your frame of reference is?
Uncertainty in Measurement
• Estimation and Error
– Significant Figures
– Reliability - Accuracy and Precision
Is this number accurate? Is it precise?
Is it the same as 2 g? 2.2 g? 2.24 g?
2.240 g? Which measurements are the most
precise? Most accurate?
The “Dart Board” on a line
• Below is the range of possible values with the
“bullseye” or “true” value located somewhere amidst
the data.
The “TRUTH”
2.1 2.3 2.4 2.5 2.6 2.8 2.9
X precise?
X precise?
N=7
Mean = 2.51
Median = 2.5
Uncertainty in Measurement
When enough measurements are made there
will be values that are larger and smaller than
the mean. Those that are too far away from the
other values, skew the mean and affect our
understanding of the “truth”
All measurements are done by humans and
are reflective of how confident the
scientist is in their measurement tool and
technique.
Every measurement is an “estimate”.
Depending on your measurement device
you will not be 100% certain about the
quantity being measured.
There are always
limitations in the
measuring equipment
and in the
ability of the
person using
the equipment.
Measured quantities
are properly reported
in such a way that
only the last digit
is uncertain.
All digits of a measured
quantity, including
the uncertain one,
are called
significant figures.
The greater the number
of significant figures,
the greater the
implied certainty of
the measurement.
This scale
can report
only 2
significant
figures.
The first
measured #
is certainly 2.
The second #
must be
estimated.
105
The reading
could be
reported as
28 or 29...
But it could not
be reported as
28.5
A reading of 28.5
implies that ones
were measured
and tenths
estimated.
Uncertainty in Measurement
• Estimation and Error
– Reliability - Accuracy and Precision
– Significant Figures
How many sig figs (marked values plus one estimate) are in the
measurements below
• 6.751 g
• 0.157 kg
4
__________
3
__________
• 28.0 ml
3
__________
• 2500 m
2
__________
• 0.070 g
2
__________
• 30.07 g
4
__________
• 0.0067 cm
2
__________
Sig figs are the
only digits that
matter in a
measurement.
Important Sig Fig Info
When a calculation involves
measurements with different
numbers of significant figures,
the answer should have the
same number of significant
figures as the LEAST in the
measurements.
Important
length X width X height = volume
2 cm X 5.5 cm X 2.258 cm =
24.838
3
cm
Can we REALLY know the volume to
thousandths of a cubic centimeter?
Important
length X width X height = volume
2 cm X 5.5 cm X 2.258 cm =
24.838
3
cm
What should be the answer?
Important
length X width X height = volume
2 cm X 5.5 cm X 2.258 cm =
24 or 25 cm3
20
3
cm
Rules for assigning significance
1. Digits other than zero
are always significant.
Rules for assigning significance
1. Digits other than zero
are always significant.
6 ml
6.6 ml
66.24 ml
Rules for assigning significance
1. Digits other than zero
are always significant.
6 ml
6.6 ml
66.24 ml
1
2
4
Rules for assigning significance
2. Rules for zeros:
Rules for assigning significance
2a. A single zero BEFORE
the decimal point
is NEVER significant.
Rules for assigning significance
2a. A single zero BEFORE
the decimal point
is NEVER significant.
0.6 ml
Rules for assigning significance
2a. A single zero BEFORE
the decimal point
is NEVER significant.
0.6 ml
1
Rules for assigning significance
2b. Final zeros AFTER
a decimal point are
always significant.
Rules for assigning significance
2b. Final zeros AFTER
a decimal point are
always significant.
0.6 ml
6.0 ml
6.60 ml
Rules for assigning significance
2b. Final zeros AFTER
a decimal point are
always significant.
0.6 ml
1
6.0 ml
2
6.60 ml
3
Rules for assigning significance
2c. Zeros BETWEEN two
significant figures are
always significant.
Rules for assigning significance
2c. Zeros BETWEEN two
significant figures are
always significant.
6006 ml
6.02 g
0.600 kg
Rules for assigning significance
2c. Zeros BETWEEN two
significant figures are
always significant.
6006 ml
4
6.02 g
3
0.600 kg
3
Rules for assigning significance
2d. Zeros used ONLY to
space the decimal are
never significant.
Rules for assigning significance
2d. Zeros used ONLY to
space the decimal are
never significant.
100 g
0.001 ml
0.000602 ml
Rules for assigning significance
2d. Zeros used ONLY to
space the decimal are
never significant.
100 g
1
0.001 ml
1
0.000602 m 3
Scientific Notation
Only shows significant values!
• Number is separated into 2 parts
– 1 must be a value between 1 and 10
PREFIX
– 2  the power of ten that the prefix is
multiplied by to reflect the size of the value
MAGNITUDE
Rules for assigning significance
2e. Scientific notation
6.02 X 10
23
atoms
Rules for assigning significance
2e. Scientific notation
6.02 X 10
23
atoms
Any digits BEFORE the X
are always significant.
Rules for assigning significance
2e. Scientific notation
6.02 X 10
23
atoms
The powers of 10
are never significant.
One last hint about
significant figures:
Accepted equalities,
like 1 foot equals 12 inches,
are considered to have an
INFINITE number of
significant figures.
Important
You will probably be required
to used significant figures in
college chemistry class when
rounding off calculations.
Find Sig Figs
• Sig figs are the only digits that matter in a
measurement. They are always written to include all
marked values plus your estimate.
• 142 g
• 0.073 s
• 1.071 cm
• 70,810 kg
• 5.00 mg
• 55.320 pm
• 1.010 fg
What are the correct measurements?
Rounding Rules - Wrong
• When you round off, you change the value of the
number, unless you round off a zero. Remember
that "rounding off" a zero does not change the
value of the number being rounded.
• Following the old rules, you can round a number
down in value four times (rounding with one,
two, three, four) compared to rounding it
upwards five times (five, six, seven, eight, nine).
• This cannot be allowed if we are to determine the
TRUTH
Rounding Rules Wrong
• On average you would be changing values in the
sample downwards 4/9ths of the time, compared
to changing values in the sample upward 5/9ths
of the time.
• This means the average of the values AFTER
rounding would be greater than the average of
the values BEFORE rounding.
• This is not acceptable as we search for the truth.
New Rules – Say What?
• If it is less than 5, drop it and all the figures to the
right of it.
• If it is more than 5, increase by 1 the number to be
rounded, that is, the preceding figure.
• If it is 5, round the number so that it will be even.
Keep in mind that zero is considered to be even
when rounding off.
Using
YOUR
calculator.
Problem #1:
(10.25) (5.74 X
4
10 )
give the answer in
scientific notation
=
Problem #1:
(10.25) (5.74 X
588350
4
10 )
=
Problem #1:
(10.25) (5.74 X
4
10 )
=
588350
significant figures?
Problem #1:
(10.25) (5.74 X
5.88 X
4
10 )
5
10
=
Problem #2:
(6.2 X
-12
10 )
(3.87 X
9
10 )
give the answer in
scientific notation
=
Problem #2:
(6.2 X
-12
10 )
(3.87 X
9
10 )
0.023994
significant figures?
=
Problem #2:
(6.2 X
-12
10 )
(3.87 X
2.4 X
-2
10
9
10 )
=
Problem #3:
(6.02 X
23
10 )
(1.05 X
6.32 X
35
10
12
10 )
=
Spark Happy Friday 09.09.11
• Please read the directions, complete the
worksheet and the sentence.
• This is a race. To the victor goes the spoils. To the
losers go the smegma.
Dimensional Analysis the most important math
in all of chemistry!!
Dimensional Analysis used to convert from one
type of unit to another.
Dimensional Analysis treats numbers and
units equally.
First write what is given.
Then multiply by fractions
equal to 1 to change
the units.
WHAT DOES THIS MEAN???????
Consider what happens when you
divide like terms in math….
They cancel because dividing anything
by itself = 1…..Right?
When the only units NOT canceled
are the units asked for,
the problem is solved.
A problem:
How many cups of oil
are in a barrel of oil?
Known equalities:
1 barrel = 42 gallons
1 gallon = 4 quarts
1 quart = 4 cups
Step 1: write what is given.
1 barrel
Step 1: write what is given.
1 barrel
Step 1: write what is given.
1 barrel
This line means divide by.
Step 1: write what is given.
1 barrel
This line means multiply by.
Step 2: multiply by fractions
equal to one.
1 barrel
Step 2: multiply by fractions
equal to one.
1 barrel
What units
go here?
Step 2: multiply by fractions
equal to one.
1 barrel
barrels
Now we'll be able to
cancel barrels.
Step 2: multiply by fractions
equal to one.
What units
go here?
1 barrel
barrels
Step 2: multiply by fractions
equal to one.
1 barrel
gallons
barrels
Step 2: multiply by fractions
equal to one.
1 barrel
1 barrel = 42 gallons
1 gallon = 4 quarts
1 quart = 4 cups
gallons
barrels
What numbers will make
this fraction equal to 1?
Step 2: multiply by fractions
equal to one.
42
gallons
1 barrel
1 barrels
Step 2: multiply by fractions
equal to one.
42
gallons
1 barrel
1 barrels
Barrels have been
converted to gallons.
Step 2: multiply by fractions
equal to one.
42
gallons
1 barrel
1 barrels
What units go here?
Step 2: multiply by fractions
equal to one.
42
gallons
1 barrel
1 barrels
gallons
Step 2: multiply by fractions
equal to one.
42
gallons
1 barrel
1 barrels
gallons
What units go here?
Step 2: multiply by fractions
equal to one.
42
gallons
quarts
1 barrel
1 barrels
gallons
Step 2: multiply by fractions
equal to one.
42
gallons
quarts
1 barrel
1 barrels
gallons
1 barrel = 42 gallons
1 gallon = 4 quarts
1 quart = 4 cups
And the numbers are?
Step 2: multiply by fractions
equal to one.
42
gallons
4 quarts
1 barrel
1 barrels
1 gallon
Step 2: multiply by fractions
equal to one.
42
gallons
4 quarts
1 barrel
1 barrels
1 gallon
Gallons have become quarts.
Step 2: multiply by fractions
equal to one.
42
gallons
4 quarts
1 barrel
1 barrels
Are we done yet?
1 gallon
Step 2: multiply by fractions
equal to one.
1 barrel
42 gallons
4 quarts
1 barrels
1 gallon
What units go here?
Step 2: multiply by fractions
equal to one.
1 barrel
42 gallons
4 quarts
1 barrels
1 gallon
quarts
Step 2: multiply by fractions
equal to one.
1 barrel
42 gallons
4 quarts
1 barrels
1 gallon
And here?
quarts
Step 2: multiply by fractions
equal to one.
1 barrel
42 gallons
4 quarts
cups
1 barrels
1 gallon
quarts
Step 2: multiply by fractions
equal to one.
1 barrel
42 gallons
4 quarts
cups
1 barrels
1 gallon
quarts
1 barrel = 42 gallons
1 gallon = 4 quarts
1 quart = 4 cups
And the numbers are?
Step 2: multiply by fractions
equal to one.
1 barrel
42 gallons
4 quarts
4 cups
1 barrels
1 gallon
1 quart
Quarts have become cups.
Step 2: multiply by fractions
equal to one.
1 barrel
42 gallons
4 quarts
4 cups
1 barrels
1 gallon
1 quart
Have we worked the problem?
Step 2: multiply by fractions
equal to one.
1 barrel
42 gallons
4 quarts
4 cups
1 barrels
1 gallon
1 quart
All units have been canceled
except those we are looking for.
Step 3: DO THE MATH.
1 barrel
42 gallons
4 quarts
4 cups
1 barrels
1 gallon
1 quart
We are ready to punch
the buttons on the calculator.
Step 3: DO THE MATH.
1 barrel
42 gallons
4 quarts
4 cups
1 barrels
1 gallon
1 quart
1 barrel = 672 cups
Another problem:
A music CD costs 12 dollars.
There are 16 songs on the
CD. How many cents does
each song cost?
What are we given:
A music CD costs 12 dollars.
There are 16 songs on the
CD. How many cents does
each song cost?
What are we asked for:
What are we given:
COST PER CD
A music CD costs 12 dollars.
There are 16 songs on the
CD. How many cents does
each song cost?
What are we asked for:
COST PER SONG
Write what is given:
12 dollars
CD
Multiply by fractions equal to 1:
12 dollars
CD
What do we want
to cancel?
Multiply by fractions equal to 1:
12 dollars
CD
Where does it go?
Multiply by fractions equal to 1:
12 dollars
CD
CD
Multiply by fractions equal to 1:
12 dollars
CD
CD
What goes here?
Multiply by fractions equal to 1:
12 dollars
CD
CD
songs
Multiply by fractions equal to 1:
12 dollars
CD
CD
songs
And the numbers are?
Multiply by fractions equal to 1:
12 dollars 1 CD
CD
16 songs
Multiply by fractions equal to 1:
12 dollars 1 CD
CD
16 songs
What are our units?
Multiply by fractions equal to 1:
12 dollars 1 CD
CD
16 songs
dollars per song
Multiply by fractions equal to 1:
12 dollars 1 CD
CD
16 songs
What goes here?
Multiply by fractions equal to 1:
12 dollars 1 CD
CD
16 songs
dollars
Multiply by fractions equal to 1:
12 dollars 1 CD
CD
16 songs
And here?
dollars
Multiply by fractions equal to 1:
12 dollars 1 CD
CD
16 songs
cents
dollars
Multiply by fractions equal to 1:
12 dollars 1 CD
CD
16 songs
cents
dollars
And the numbers are?
Multiply by fractions equal to 1:
12 dollars 1 CD
CD
16 songs
100 cents
1 dollar
Multiply by fractions equal to 1:
12 dollars 1 CD
CD
16 songs
100 cents
1 dollar
What are our units?
DO THE MATH:
12 dollars 1 CD
CD
16 songs
cents per song
100 cents
1 dollar
DO THE MATH:
12 dollars 1 CD
CD
16 songs
100 cents
1 dollar
75 cents / song
Practice
Take your age and convert it into seconds! Do
it!
Years to days to hours to minutes to seconds.
Percent Party!!!!!!!!
1. 7.9 g fat
2. 1012 g milk
3. 1.05% fat
4. 10.6 g fat 0.0106 kg fat
5. 546.48 g nonfat ingredients
6. 0.211% fat
7. 21.9 g sat fat
8. 2.29 g unsat fat
9. 7.49 g sat fat
10. 624 g fat
11. Polar Bear milk = 280.8 Cal
12. 2.86 kg seawater
13. 0.49 g Mg
14. 537 kg magnesium sulfate
Cow milk = 29.25 Cal
•
CooCooForCocoaSpark
sorry for all the text!
The study was published in Chemistry Central Journal.
• Comparing the antioxidants in chocolate vs. the so-called super-fruits –
acai berries, blueberries, cranberries, researchers at the Hershey Center
for Health & Nutrition found that there was a greater antioxidant capacity
per gram in cocoa powder than in fruit powders. Antioxidants inhibit the
oxidation of cell molecules that turn into free radicals.
• Polyphenols and flavonols are the two main groups of antioxidants.
Foods high in polyphenols and flavonols are the super foods and now
cocoa powder has been added to this list.
While the flavonol content in most fruit powders averaged at less than 10
milligrams per gram of powder, it was found to be 30.1 milligram for one gram
of cocoa powder. Per serving of 40 grams of dark chocolate had more than
500 milligrams of flavonols, cocoa powder with 400 milligrams and the fruit
juices at one cup (220g) per serving, had less than 200 milligrams of
flavonols. Convert each of these ratios to percent values so they can be
more easily compared.
1,000 milligrams of polyphenol content was found in each serving of
dark chocolate (40 grams). What is percent of dark chocolate is
polyphenol?
• The flavonol content of cocoa powder was found to be higher than all of
the fruit powders.
• Similar results were found when they compared dark chocolate and cocoa
to fruit juices.
• The researchers studied the antioxidant activity for a 40 gram serving of
dark chocolate and cocoa powder as compared with a one cup serving of
fruit juice. With the exception of pomegranate juice, the dark chocolate
showed significantly higher antioxidant activity per serving than the other
fruit juices.
• Researchers have noted that the dark chocolate and cocoa powder used
in the study contained natural or non-alkalized cocoa. Alkalization
improves the taste, color and dispersion properties of the cocoa but
destroys the polyphenolic compounds it contains. Bad news for hot
chocolate lovers, though, is that their drink of choice offers little in the way
of antioxidants (due to the way it's processed).
Communication in Science
• Statistical Analysis
– Mean  What was the average value? (bell
curve), aka “true” value,
central tendency
• How do other measurements compare to the mean?
– Percent Error  how far off was the
measurement from the
accepted value?
SPARK
Monday, September 12, 2011
Find the volume of a cube with a length
measurement that has only 1 sig fig
(ex: 3 cm)
Find the volume of a cube with a length
measurement containing 2 sig figs
(ex: 3.3 cm)
Find the volume of a cube that has a length
measurement containing 3 sig figs
(ex: 3.25 cm)
Which measurement is most precise? Most
accurate?
Dimensional Analysis Spark
09/13/2011
Density is a conversion factor between the mass and
volume of a sample.
Mercury has a density of 13.6 g/mL.
What is the mass of 2.42 gallons of mercury?
(1 gallon = 3.78 L)
Complete the Measurement Lab
Calibrate your balances before use.
Send group reps up to deliver the data.
Part of your lab grade rests on getting me the
data ASAP!
If you are finished, work on the conversion
worksheet (#1-19) that is due Wednesday
Experimental error is a
comparison of a value obtained
by measurement to an
accepted theoretical value.
THIS IS A MEASURE
OF ACCURACY!
The accepted theoretical
value is either obtained
from reference material
or calculated.
experimental _ theoretical
value
value
X 100
% error =
theoretical value
Exp Error Practice Problem.
A student determines experimentally
that the density of water is
0.85 grams per cubic centimeter.
Calculate the student's
experimental error.
0.85 g
_
1.00 g
X 100
% error =
1.00 g
% error = 15 %
Exp Error Practice Problem.
Before drying, a sample weighs 5.6 g.
After drying, it weighs 4.2 g.
The sample is known to contain
3.0 grams of water.
Calculate the experimental error.
% error = 53 %
1.4 g
_
3.0 g
X 100
% error =
3.0 g
Advanced Stats
• Mode, median, range
• (average) Deviation from the mean
• Standard Deviation – the mean of the
mean (Estimated Standard Deviation, <20)
– how true is the “true” value?
• Normal Distribution
This is making
me angry!!!!!!!!!!
What About Bad Data?
Q test
• Q = abs. value of suspect value – closest value
range of data
N
3
4
5
6
7
8
9
10 15
Qc
0.94 0.76 0.64 0.56 0.51 0.47 0.44 0.41
What About Bad Data?
Q Test
Use only one time!
Example: 9.43, 8.95, 8.97, 8.96, 8.93 g/cm3
N
Qc
3
4
5
6
7
8
10 15
0.94 0.76 0.64 0.56 0.51 0.47 0.44 0.41
N>15
Critical Q value is 2.6 x standard deviation
9
S = Standard Deviation
• Mean of the mean
• Square root of the sum of the squared
(devMean) divided by n-1
• In a normal distribution…
• 68% of all measurements fall within one
standard deviation of the average. 95% of all
measurements fall within two standard
deviations of the average.
Steps for Standard Deviation
•
•
•
•
•
•
Find mean of data
Find individual deviations from mean
Square all individual deviations from mean
Sum all squared deviations from mean
Divide by N or n-1
Square root the quotient
Practice Data: 100m Dash Times
X
Time (sec)
DvMean
DvMean2 Mean
1
9.77
0.07
0.0049
2
9.78
0.06
0.0036
9.90
Truth?
StDev
3
9.84
0.00
0.00
0.077
4
9.85
0.01
0.001
Con.
5
9.96
0.12
0.0144
0.04
6
10.20
Practice Data: 100m Dash Times
X
Time (sec)
DvMean
DvMean2 Mean
1
9.77
0.07
0.0049
2
9.78
0.06
0.0036
9.84
9.90 (Q)
StDev
3
9.84
0.00
0.00
0.077
4
9.85
0.01
0.001
Con.
5
9.96
0.12
0.0144
0.04
6
10.20 Boo!
• About 68% of values drawn from a standard
Distribution for 100 m
normal
distribution are within one standard
Dash Times (s)
deviation away from the mean;
= 0.077
• About 95% of the values are within SD
two
standard deviations and
• About 99.7% lie within three standard
deviations.
• This is known as the "68-95-99.7 rule" or
the "empirical rule."
9.686
9.763
9.84
9.917
9.994
Confidence
• 2.16 +/- 0.05 cm3 at 95 % confidence means that
there is a 95% probability the “true” value lies
between 2.11 cm3 and 2.21 cm3
• IT DOES NOT MEAN THAT WE ARE
CONFIDENT OF THE RESULT ONLY
95% OF THE TIME !
• About 68%95.4%
of values
drawn
a standard
of the area
underfrom
the curve
normal distribution are within one standard
deviation away from the mean;
• About 95% of the values are within two
standard deviations and
• About 99.7% lie within three standard
deviations.
• This is known as the "68-95-99.7 rule" or
the "empirical rule." 2.16
2.11
2.16
95.4% probability the true value
lies here
Confidence depends on the size of your
data sample (N) and the mean as it relates
to the spread of the data
• + or - Δ = t * S/N
N-1
1
2
3
4
5
6
7
8
9
10
15
Infin
t
12.7 4.30 3.18 2.78 2.57 2.45 2.36 2.31 2.26 2.23 2.13 1.96
Reporting
• Mean = 1.015 g/cm3 with estimated deviation of
0.006 g/cm3
• Density = 1.015(6) g/cm3
• Density is 1.015 +/- 0.006 at 95% confidence limit
• This is how science can tell if it is “right” or if it has
found the “truth” in nature.
Density Spark
• An unknown metal was found to have a mass of 3.54
grams and displaced 0.53 mL of water what is the
density of the metal?
Known Densities (g/mL)
Tellurium has a density of 6.4
Nickel has a density of 8.9
Cerium has a density of 6.657
– What is the identity of the metal?
– What is your percent error?
– Is the data accurate?
– Is it precise?
Calculating
density makes me really
– Where might errors exist in the
data?
happy!
DANG DIMENSIONAL ANALYSIS
• The diameter of a palladium atom is 140 picometers;
the picometer is equal to 1 x 10-12 m; the equatorial
diameter of the Earth is 40 075.02 km
– How many Palladium atoms would it take to encircle the Earth at the
Equator?
– If one palladium atom weighs 1.77 x 10-22 g, then what is the mass of
the “palladium ring” circling the Earth?
• In America, a car’s gas efficiency is measured in miles
per gallon. In Europe, it is measured in km/L. If your
car’s gas mileage is 40.0 mi/gal, how many liters of
would you need to complete a 142 km trip?
– (1 km = 0.6214 miles; 1 gallon = 3.7884 L)
9/15/2011 Birthday Spark for
Tommy Lee Jones
(p. 1)
• In America, a car’s gas efficiency is measured in miles
per gallon. In Europe, it is measured in km/L. If your
car’s gas mileage is 40.0 mi/gal, how many liters of
gas would you need to complete a 142 km trip?
– (1 km = 0.6214 miles; 1 gallon = 3.7884 L)
9/15/2011 Birthday Spark for
Tommy Lee Jones
Black Hole Density
If the mass of the sun (m = 2 x 1033 g) were to collapse into a
“spherical” black hole with a radius of 300 cm, then what is the
density of the black hole? (Vsphere = 4/3ér3)
Earth’s Density is 5.515 g/cm3
A Volkswagen Beetle has a mass of 802 000 g. How many beetles would it take to
equal this black hole sun of relative size?
http://apod.nasa.gov/htmltest/gifcity/rsgrow.mpg
Friday Spark 09/16/2011
Phosphaturia is a medical condition of
too much phosphorus in your urine. It
can be a symptom of a kidney
dysfunction. If 1 gallon of urine
(density = 1.035 g/mL) produced 6.5
grams of phosphorus, then what is
the percent concentration of
phosphorus in the urine?
(1 gallon = 3.78 L)
Combining images from the Hubble
Space Telescope and the Chandra Xray Observatory, NASA offers a
glimpse into a dazzling ring of black
holes 430 million light years from
Earth.
The image shows two
galaxies, known
collectively as Arp 147,
that collided in the past,
triggering a wave of star
formation (blue ring in
galaxy at right).
A number of these stars exploded as supernovae,
producing black holes. Some of these, thought to
weigh 10 to 20 times as much as the sun, shine
brightly in X-rays (pink blobs) as they rob
matter from companion stars.
Measurement Investigations
Verify the density of distilled water.
What is the density of hot water?
What is the density of cold water?
Determine the density of other liquids like tap
water, saltwater, or ethanol.
Determine the density of a known metal.
Determine the density of a penny*.
Calculate the thickness of a penny.
What is the thickness of aluminum foil?