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Catalyst: Happy Wednesday!Which quantity is larger? 1) 4.5 x 1034 or 6.5 x 1020
2) 2.3 x 10-3 or 4.5 x 10-6
3) 5000 or 5 x 105
• HW Due: Read textbook pp. 224-229• Do problems: pp. 233 #1, 2, 4, 5, 6(a), 8(a)
• Tonight’s HW: Read textbook pp. 230, 236-240• pp. 233 #6(b, c, d), 7(c), 8(b)• Valence electron review worksheet!
Lesson Objective
I will be able to explain what a “mole” in chemistry means!
Agenda
• Catalyst• HW Review• Intro to Molar Conversions Worksheet• Exit Slip
HW: pp. 233 #1, 2, 4, 5, 6(a), 8(a)
1. A mole is the number of atoms in exactly 12 g of carbon-12.
2. There are 6.022 x 1023 particles in one mole. “Particles” refers to atoms, ions, or molecules.
4. 1 mol of nickel(II) and 1 mol of nickel(III) both contain exactly 6.022 x 1023 ions. – (This is like asking “which is heavier: 1 pound of feathers
or a 1 pound brick?” They are both 1 pound! Similarly, 1 mol of anything always contains 6.022 x 1023 of whatever is being counted.)
5. 1.11 mol Pt is more than 6.022 x 1023 atoms. – (This is the same as asking whether 1.11 is more or less
that 1.00 because 1.00 mol = 6.022 x 1023 particles. 1.11 is more than 1.00.)
HW Review Continued…
• 6(a). 1.204 x 1024 ions Fe3+
• 8(a). 0.500 mol H2O
• We will work through how to answer these questions in today’s lesson!
Focus Questions Today
What is a mole, besides a small mammal or a growth on your body, and what is it good for, besides digging holes?
Do all moles weigh the same amount?
Analogy: Think of the term dozen...How many doughnuts are in a dozen?How many eggs are in a dozen?
How many bricks are in a dozen?
How many ostriches are in a dozen?
Get Ready… You’ll know what a “MOLE” is soon
Notes: Introducing the Mole
Counting By WeighingAtoms and molecules are too small to seeWe measure out atoms by using a number
called the mole!!!!
What is the mole? (Notes)
• A mole is the number of atoms in 12 grams of carbon-12.
• There are 6.022 x 1023 atoms in 12 grams of carbon-12.
• 1 mole (mol) = 6.022 x 1023 particles.
A mole is very similar to a dozen. But instead of
meaning 12 of something, it means
6.02 x 1023 of something.6.02 x 1023 =
602,000,000,000,000,000,000,000Or
Six hundred and two sextillion!
1 mole (mol) = 6.02 x 1023
This number is a constant.
The number of particles in 1 mole is called
Avogadro’s Number!
6.02 x 1023
Avocado Avogadro
So one mole of...
...doughnuts is 6.02 x 1023
doughnuts
... Ostriches is 6.02 x 1023 ostriches
...oxygen atoms is 6.02 x 1023 atoms of oxygen (O)
...oxygen molecules is 6.02 x 1023
molecules of oxygen (O2)
Review- The mole - MEMORIZE1 mole = 6.02 x 1023 particles
6.02 x 1023 is called Avogadro’s number
The periodic table is based on the molar mass of carbon (C)
THE MOLE -- Why?
Why is the mole useful to us as chemists??
Make a dot on your paper with your pencil.
Guess how many atoms of Carbon graphite are in that dot.
25 million atoms in that tiny dot!
Say it!
• How many particles are in 1 mole?–6.02 x 1023
• How many atoms are in 1 mole of carbon?• How many atoms are in 1 mole of sodium?• How many atoms are in 1 mole of helium?• How many ducks are in 1 mole of ducks?
Conversions
particles
MOLES
How many particles are in 1 mole of something?
6.02 x 1023To convert from number of moles to number of particles, multiply the number of moles by the conversion factor:
6.022 x 1023
1 mol
Example 1:
• How many particles are in 2.00 moles?
• Multiply2.00 mol x 6.022 x 1023 particles = 12.04 x 1023
1.00 mol
How many particles are in 1 mole of something?
6.02 x 1023To convert from number of particles to number of moles, multiply the number of moles by the conversion factor:
1 mol___6.022 x 1023
Example 2:
• How many moles is 3.01 x 1022 atoms?
• Multiply(3.01 x 1022 atoms) x __1.00 mole = 0.5 x 10-1 mole
6.022 x 1023 atoms
Scientific notation… 0.5 x 10-1 mole = 5.0 x 10-2 mole
Agenda
• Catalyst• HW Review• Intro to Molar Conversions Worksheet• Exit Slip
Exit Slip1. Draw the Lewis Dot structure for the
molecule: HBr2. How many molecules of HBr are in 2.00 mole
of HBr?3. Which has more atoms: A mole Platinum or a
mole of tin?
Random Mole Facts!• Since the Earth has a radius of about 6400 km, its volume is
approximately 1021 m3. Since about 500 large grapefruit will fit in one cubic meter, it therefore follows that a mole of grapefruit would have approximately the same volume as the Earth.
• If you had exactly one mole of sheets of paper, you could make one million equal stacks from sea level on the earth that would pass the sun.
• If you had a mole of pennies, you could give out enough money to everyone in the world so that they could spend a million dollars every hour, day and night, for the rest of their lives.