Moley, moley, mole…

Objective: SWBAT perform stoichiometric conversions

from mole to mass, from mass to mass

Catalyst: What is .25 of a dozen? If a dozen hotdogs weighs 3 kilograms, how much does 3 dozen hotdogs weigh?

Agenda

Catalyst OMG! YOUR NEW BFFL! The mole. Bring back the train tracks Exit Question

What is a mole to us chemists? A benign overgrowth of cells because of

a failure in mitosis? NO! But gross… A rascly little rodent? NOOOO! A TV show featuring celebrities? NOOOOO! Then WHAT IS IT?????!!!???!?!?!???!!!!

The Mole

Think of the term “a dozen”…

How many donuts are in a dozen?

How many eggs are in a dozen?

The Mole

Just like a dozen refers to 12 objects…

The Mole

Just like a dozen refers to 12 objects…

… the mole refers to …

The Mole

Just like a dozen refers to 12 objects…

… the mole refers to …

6.02 x 1023

particles

The Mole

This number is called Avogadro’s number…

6.02 x 1023

602,000,000,000,000,000,000,000

ATTENTION! ATTENTION!

Today’s goal is for you to learn how to “Set-up” these problems. Therefore, even if you do not have a calculator you need to make sure that you set-up the problems in your notes.

What’s the point of all this?

Key Point #1:Avogadro's number is used to convert between grams, moles, and atoms/molecules.

It all relates back to the mole…

Guess what’s coming back…

TRAIN TRACKS!!!

Step 1: What to what?

Step 2: Write conversion factor(s)

Step 3: Train tracks

Avogadro’s Number

Conversion factor:

1 mol = 6.02 x 1023 atoms

1 mol = 6.02 x 1023 molecules

1 mol of pennies = ?

You may want to copy this down…hint hint cough cough

Avogadro’s Number

1 mol = 6.02 x 1023 atoms

How many atoms are in .25 mol N2?

Avogadro’s Number

1 mol = 6.02 x 1023 atoms

How many atoms are in .25 mol N2?

.25 mol N2

Avogadro’s Number

1 mol = 6.02 x 1023 atoms

How many atoms are in .25 mol N2?

.25 mol N2

1 mol N2

6.02 x 1023 atoms

I guess you can use your calculator for this…

Scientific Notation on the calculator If you need to type 6.02 * 1023

Type “6.02 ‘EE’ 23” instead.

SAVE TIME AND LOOK COOL!

Your turn! Whiteboards.

How many atoms are in 2 moles of C12H22O11?

OOOH, I want some more train tracks! Key Point #2:

Molar mass is the total mass in one mole of a substance.

1 mol X = ____ g X

BUT HOW DO WE FIND THE MASS???

1 mol Oxygen = 16 g 1 mol of He = ?

Molar Mass

1 mol C =

Molar Mass

1 mol C = 12 g C

Molar Mass

1 mol Na =

Molar Mass

1 mol Na = 23 g Na

Molar Mass-Can you figure out this one??

1 mol CO2 =

Molar Mass

1 mol CO2 =

C = 12 g O = 16 gO = 16 g

Molar Mass

1 mol CO2 =

C = 12 g + O = 16 g + O = 16 g

Molar Mass

1 mol CO2 = 44 g CO2

C = 12 g + O = 16 g + O = 16 g

Molar Mass

1 mol KNO3 =

K = + N = + O =

Molar Mass

1 mol KNO3 =

K = 39 g + N = 14 g + (3) O = 16 g

Molar Mass

1 mol KNO3 = 101 g

K = 39 g + N = 14 g + (3) O = 16 g

Molar Mass- Let’s try a problem

1 mol KNO3 = 101 g If we have 3.5 moles of KNO3, how many

grams would we have?

WHAT to WHAT?

Molar Mass

1 mol CH4 =If we have 20 grams CH4, how many

moles of CH4 do we have?

Step yo’ game up!

How many atoms are there in 14 grams?

Independent Practice

1, 11, 16… we will go over to show you how to solve this hilarious assignment!

Attach your work on a separate sheet of paper.

Exit Question

How many molecules are in a mole of NH4?

How many grams are there in 2.3 moles of NH4?