Scientific Notation
Scientific NotationScientific NotationVery large or small
numbers can be written in scientific notation.Scientific notation
uses decimals and a power of 10 to represent the original number.To
write a number is scientific notation, the number must be written
with a decimal point after the first digit.Converting to Scientific
NotationWrite out the entire number.Count the number of places you
move the decimal point so that the number is after the first
digit.If you moved the decimal to the LEFT, write 10 raised to the
positive of the number of places you moved the decimal.If you moved
the decimal to the RIGHT, write 10 raised to the negative of the
number of places you moved the decimal.Write In Scientific
Notation10250000.0025798100000.2365Measuring AccuratelyThe extent
to which a measured value agrees with the accepted valuePercent
error between experimental or calculated numbers and accepted
number Degree of exactness to which a quantity is
measured.Measurements may be precise, but may not be accurate.Based
on the scale of the measuring devise. Accuracy vs.
PrecisionAccuracyPrecision
Recording and Reporting MeasurementsWhen recording a
measurement, always record all values given by the devise and the
guess at the last place value.For example, if you measure a strip
of paper to be 5.6 cm, you would want to add one more digit to the
end of your number based on where you think the paper ends. If it
ends right on the 0.6 mark, then your value would be 5.60 cm. If it
appears to go halfway between 0.6 and 0.7 your value would be 5.65
cm.
Liquid Measurements- Meniscus Water is a sticky molecule. Water
will climb the sides of the glass. This is called the Meniscus. The
Metric SystemSpace Station IssuesThe International Space Station
(ISS) is regularly populated with Russians, Americans, Japanese,
and Europeans. Language is a problem. So math is not a problem, one
system of units has been adopted.Measure out 5 feet.How many meters
is that?
The Metric SystemMass (how heavy things are) is measured in
grams. Volume (how much space something takes up) is measured in
liters. Length (how far, long, wide something is) is measured in
meters.
Examples of Mass
A Penny weighs 2.5 grams
1 gram of pure gold is worth ~$100Examples of Volume
A Bottle of Soda 2 Liters
Gallon of Milk3.8
Litershttp://www.citysackers.com/product_info.php?products_id=370http://www.doobybrain.com/2008/07/24/new-coca-cola-2-liter-contour-bottle/
Examples of Length
A stride is approximately 1 meterA car is approximately 4
meterImportance of PrefixesWhich is easier to report?.000000003
gramsor 3 nanograms
PrefixesKing Henry Died from drinking chocolate milkKilo =
1000Hecto = 100Deca = 10Free = grams, liters, metersDeci = .1Centi
= .01Milli = .001
http://www.fanpop.com/spots/chocolate-milk/images/1297950/title/choco-milk-photoOR.King
Have Diamonds but diamonds cost moneyKilo = 1000Hecto = 100Deca =
10Base unit= grams, liters, metersDeci = .1Centi = .01Milli =
.001http://www.fanpop.com/spots/chocolate-milk/images/1297950/title/choco-milk-photo
Convert 5000 grams to kilograms
5000.g
K H D f d c mConvert 5000 millimeters to meters
Convert 15 deciliters to hectoliters
Practice Conversions9000 mL to DL.006 Km to m54 cg to g.408 L to
dL905 Hm to cm9 g to Kg
Importance of the Metric System
Chemists work across the globe to further our understanding.
We need to be able to share our information so that we can make
discoveries more quickly. ConversionsConversions Simplify
LifeConversions allow you to represent the same amount in different
units.
http://www.fiftybucksaweek.com/tag/eggs/Consider EggsEggs are
not sold individually. You buy eggs or 1 dozen.
1dozen = 12 eggs.
http://www.reuters.com/article/idUSTRE67J34H20100820Units1 dozen
= x dozen__________ __________12 eggs 36 eggs1 dozen = x
dozen_________ ____________12 eggs 24 eggs1 dozen = x
dozen_________ __________12 eggs 15 eggs32?Setting Up A
ConversonMake sure you have the same units on the top and the same
units on the bottom 1 dozen = x dozen ___________ _____________ 12
eggs 15 eggsStep One: Cross MultiplyStep Two: DivideStep Three:
Check Units1 dozen = x dozen_____________ ________________12 eggs
30 eggsTry one yourself.== xPressure Conversions1 atm = 760 Torr4
atm = ???1 atm 4 atm760 Torr X Torr=In chemistry we dont use
dozens. We use Moles.
A mole is a number of particles.
Number of Particles1 Mole = 6.02 x 1023 Particles
60,200,000,000,000,000,000,000,000 ParticlesMole ConversionsOne
mole of an element has a specific mass. We can convert between
moles and grams. 1 mole of Carbon = 12 grams1 mole of Carbon = 12
gramsHow many moles is 30 grams of Carbon?1 mole of Oxygen = 32
gramsHow many moles is 59 grams of Oxygen?Math ReviewYou have 20
beads; 6 of them are red. What is the percentage of red beads?How
much is 13% of 54?How much is 54% of 120?How much is 98% of 6?1
mole = 40 grams. How many moles is 60 grams?1 mole = 22.4 liters.
How many liters is 3 moles?12 Eggs = 1 dozen eggs. How many eggs is
4.66 dozen?100 cents = 1 dollar. How many dollars is 14,000 cents?1
mole = 32 grams. How many grams does 2.5 moles weigh?1 atm = 760
Torr. How many Torr is 3.4 atms?Significant FiguresSignificant
FiguresWhen using a measuring device, the last digit is always an
estimate.To make sure all calculations with measurements are
accurate, we have to make sure our answers do not have more digits
than the original measurements.Scientists use significant figures
to help solve this issue.The more sig figs a measurement has the
more precise it is.What Numbers are Significant?All digits other
than zero are significant numbers.Zeros are significant if:It is
surrounded by two non-zero digitsIf more than one zero is
surrounded by non-zero numbers, all the surrounded zeros are
significantIf a decimal is present, all the zeros after the first
non-zero number are significantAll numbers written in scientific
notation are significantSteps to Counting Sig FigsStep 1: Is the
decimal point present or absent?Present: start from leftAbsent:
start from rightStep 2: Start counting with the first number that
isnt zeroStep 3: Once you start counting, count everything,
including zeros
The Rules of Zero
AtlanticAbsentRightPacificPresentLeftHow many significant
figures?0.5543 Sig FigsThe Rules of Zero
Atlantic
RightPacific
LeftHow many significant
figures?8004AtlanticAbsentRightPacificPresentLeft4 Sig FigsThe
Rules of Zero
AtlanticAbsentRightPacificPresentLeft1.0450How many significant
figures?5 Sig FigsThe Rules of Zero
AtlanticAbsentRightPacificPresentLeft60650How many significant
figures?4 Sig FigsThe Rules of Zero
AtlanticAbsentRightPacificPresentLeft900.0How many significant
figures?4 Sig FigsThe Rules of Zero
Atlantic
RightPacific
LeftHow many significant
figures?733AtlanticAbsentRightPacificPresentLeft3 Sig FigsIdentify
the number of significant
figures:1.03690100000900.00.0000023690.0045010679.0
Do Now:Solve for x: x2 5 = 29How many significant figures:
0.0015018% of 105 is how much?What units would you measure the
volume of a pool in?Convert from scientific notation: 2.3 x
10-4Calculations with Sig FigsWhen you multiply or divide the
answer must have has many sig figs as the least precise number.
When you add or subtract the answer must have the same number of
digits after the decimal place as the number with the fewest digits
after the decimal place. Perform each operation:103 x 2.0300 /
50.00462.7 + 82.697695.336 452.2214684.9 x 42.32369 / 3945.0526 +
16547.9999 4521.0
GraphingGraphingRemember to SLAP ITScale- does your scale cover
all data?Label- did you label each axis with units?Axis- is your
independent variable on the x-axis and your dependent variable on
the y-axis?Plot Points- are all points properly
plotted?Investigate- have you looked for trends and relationships
between the variables graphed?Title!- does your graph have an
appropriate title?
Reference Table GraphsThere are two graphs you need to be
familiar with in your reference table. They are in Table G:
Solubility Curves at Standard Pressure and Table H: Vapor Pressure
of Four Liquids.To be able to read these graphs, you need to first
identify which graph will give you the information you need. The
title and axis labels will tell if the graph has the information
you need.Now you need to identify the scale used on each axis.Once
these steps are done, use the given information in the problem to
determine your missing information.ExampleWhat is the solubility of
NH3 at 55C?
At which temperature does NaNO3 have a solubility of 100 g
solute/100g H20?
Which liquid has a vapor pressure of 150 kPa at 90 C?
At what temperature does water have a water vapor of
101.3kPa?
Using GraphsOne important piece of information you can use from
a linear graph is the slope.To find slope, use the formula:Slope =
y2 y1 x2 x1Example:Find the slope of this graph:
