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This is the start of the Chemical Composition Unit.
***HEEEEYYY!!**** --> You should definitely look at the VIDEO called Mole D1 examples!! It's much better than this boring ppt.
Bellwork Monday 11-28-16 Numbers with nicknames
1. Summarize your Thanksgiving Break in at least 6 sentences.
2. How many is a pair of something? What do we have pairs of?
3. How many is a dozen of something? What do we count dozens of?
These numbers work well for macroscopic items, items large enough for use to see & touch.
In Chemistry, we are concerned with tiny particles (atoms, e- , molecules)…we need a way to deal with such microscopic things on a macroscopic level.
1- Students will know the mole, molar mass, and conversion factors.
2- Students will be able to convert between mass, moles, and number of atoms using conversion factors (dimensional analysis).
Numbers with Nicknames
You are smart people! Converting units
The Mole Notes
Molar conversions w/Molar highway
REMEMBER: YOU are REALLY SMART people.
How many seconds in a minute?
How many minutes in an hour?
With your elbow partner, figure out:
How many seconds are in 4.00 hours?
How many hours are in 8320 seconds?
What you just did was change units using conversion factors.
You JUST DID what we call Dimensional Analysis- AND I haven’t even taught it yet. Don’t you feel smart?
= converting(changing) between units using a conversion factor.
Conversion factor: a ratio (fraction) that equals 1, but switches your units
Any equal statement can give 2 conv. factors. Ex. 12 inches = 1 foot gives both
Take initial number and multiply by the conversion factor to switch units….
Units CANCEL if they are opposite
(one on top and one on bottom)
Make sure the units you are converting to are on top.
Example: 5.3 feet = __?__ inches
5.3 ft x _______ = in
To do the math, always :
MULTIPLY the numbers on TOP
Divide the numbers on bottom
5.3 x 12 ÷ 1
= 63.6 in
Concept first, math later
Each problem depends on using the right conversion factor, with the units in the right place.
Example: Change from yellow stars to blue circles.
This will switch units: x _______ =
This will NOT switch units: x _______ = ____2
Work with your partner to answer each question. Listen carefully!
With Math: Multi-step problems:
How many seconds in 7.00 hours?
Know 1 min = 60 sec and 60 min = 1 hr
#1 on Dimensional Analysis sheet:
3 hrs = ________ sec
What would the answer be in scientific notation?
Dimensional analysis sheet
*use the equal statements on the sheet and on the handout to solve each problem
*WE are going to do #3, 4, and 6 together
Finish the sheet as homework. – SHOW YOUR UNITS!
What’s a MOLE?
Numbers with Units are important; -help us to compare different items
When you shop at a grocery store, measure items to sell in different ways:
It is convenient to have a UNIT that stands for a certain #
1 dozen = 12 somethings
The Mole (Chemistry Unit) (animal) (face wart)
Defined: the number equal to the number of carbon atoms in 12.01g of carbon
Amadeo Avogadro: Italian Scientist;
determined the “mole” concept
“mole” = heap, pile
1 mole = 6.02 x 1023 somethings
Can be written:
a.k.a. Avogadro’s number
This HUGE number makes measuring and comparing elements reasonable-
Allows us to count atoms according to mass
count by mass? – YES!
Have you ever tried to win a jar of jellybeans by guessing the number of jellybeans in the jar?
A simple calculation could have told you the answer!
Massgroup ÷ massavg one = Number in group
Ex. Mass of all the beads ÷ mass of a single bead equals the total number of beads present.
Therefore, counting by mass!
One mole of a substance makes the atomic mass or the amu, true in grams
Called the molar mass.
1 dozen eggs vs.1 dozen bowling balls
Know relative size: smaller BIGGER
Know relative weight: lighter HEAVIER
Know # of items: both have 12 items
From a UNIT(like dozen, or MOLE), know 3 amountsdepending on the item (eggs or bowling balls, etc.)
# of things
What can you have a mole of?
1 mol He …1 mol C6H12O6 …1 mol Ba+2 …1 mol NaCl
In 1 mol CO2 molecules, you have
1 mol C atoms
2 mol O atoms -- subscripts are mole ratios!
Masses on the P.T.- stand for grams per mole of atoms (of that element) – called molar mass
Ex. C: 12.011 = 12.011 grams per 1 mol C atoms
= 12.011 grams per 6.02 x 1023 C atoms
1 mol C …1 mol C6H12O6 …1 mol Ba+2
Masses on the P.T.- stand for grams per mole of atoms(of that element) – called molar mass
How many atoms are in 1 mole of Sodium?
6.02 x 1023 , Avogadro’s number
How much does 1 mol of sodium weigh?
22.990 g, the molar mass from the periodic table!
How much does 1 mol of calcium weigh?
What has more atoms, 1 mol Na or 1 mol Ca?
NEITHER! BOTH HAVE 6.02x1023 atoms
A mole is a UNIT that stands for a NUMBER
1 mol (abbreviated) = 6.02 x 1023 items
The masses given on the periodic table stand for 1 mol of atoms of that element… = weight in GRAMS of 6.02 x 1023 atoms
1 mol Carbon vs. 1 mol Gold
EQUAL number of atoms
1 mole of elements…
Hydrogen (gas in balloon), Sulfur, Copper, and Mercury
Molar masses for each?
Find your start.
Find your end goal.
Set up the conversion factors as shown.
Do the math, keep track of units!
Mass of sample (grams)
*fill in on the back of your Periodic table*
Number of particles (atoms, molecules or formula units)
Using the molar Highway
This should now be your 2nd favorite reference tool in class.
KNOWING: 1 mole = molar mass in grams
KNOWING: 1 mole = 6.02 x 1023 particles,
We can use these amounts as conversion factors to figure out how many atoms are in a certain mass of any element.
EVERYTHING GOES THROUGH THE MOLE.
1 – find where you start (mass, mol, atoms?)
2 – find where you want to be
3 – follow the arrows & use the right conversion factors
What is the mass in grams of 3.50moles of Copper?
How many moles are in 3.79 x 1013 atoms of Calcium?
How many moles are in 10g of Al?
How many atoms?
The other way…
How many moles are in 1.22x1020 atoms of silicon?
What is the mass?
Dimensional Analysis #1-12
Mass and the Mole Worksheet
Students will be able to recognize units and associate them with certain variables; students will be able to correctly substitute problems and will be able to correctly solve math problems.
14400 seconds, 2.31 hours
Before we add in numbers, let’s get the hang of switching units first.
1- pass out deck of 15 cards to each table. (13 laminated sets total.)
2- Have them spread their cards out to check out their conversion factors.
3- Using the shapes up front, ask students to hold up the correct conversion factor to change from shape to shape.
4- after they have the hang of it, ask them to try a 2 step conversion (they will have to ignore the direct card and go through a different shape.)
Overall goal: they understand units need to be opposite to cancel. Given is always considered “on top”.
Estimated time: 10-12 minutes
Here’s where you’d pass out the Dim. Anal. Sheet, with notes at top. (#1-12, already written, Multiply top numbers, divide bottom numbers.)
By weight: fruit, candy, meats, veggies grams, lbs, oz
By volume: water, juice, soda, milk gal., fluid ounces, L, cups, qts
By number: cans of soda, eggs, juiceboxes dozen, 6-pack, 24 pack
Atoms, molecules (or formula units), ions
*talk about sets of silverware, relate it to a “formula” and how you could have a mole of silverware sets
*Make sure they leave room for the thing on right and above- will fill those in later.
e a mole of?
*talk about sets of silverware,