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.