Stoichiometry and the mole- Your new bffl November 2 2 +3 3 -1, 2.009 * 10 3

Stoichiometry and the mole- Your new bfflNovember 22+33-1, 2.009 * 103

Objective: SWBAT perform stoichiometric conversions

from mole to mass, from mass to mass

Catalyst: How many basketballs are in a dozen? How many turkeys are in a dozen? How was your break?

*This week… bring scientific calculators if you have them!

Exit Question

What do you need to do to get where you want to be in this class?

Agenda

Catalyst/Welcome Back Test Review/Tracking/Corrections 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

Avogadro’s Number

1 mol = 6.02 x 1023 atoms

1 mol = 6.02 x 1023 molecules

Why do YOU think we would do this?

Interpreting Equations

4 Fe + 3 O2 2 Fe2O3

“4 moles of iron react with 3

moles of oxygen gas toproduce 2 moles of iron(III)

oxide”Coefficients in chemical

reactions just refer to how many moles are reacting!

Interpreting Equations

C3H8 + 5 O2 3 CO2 + 4H2O

“1 mole of propane (C3H8)reacts with 5 moles of oxygen

gas to produce 3 moles of carbon

dioxide and 4 moles of water”

How many moles needed?(moles – moles)

C3H8 + 5 O2 3 CO2 + 4H2O

If you start with 10.0 molesof propane (C3H8), how many

moles of oxygen gas is neededto fully combust (react)?

How many moles produced? (moles – moles)

C3H8 + 5 O2 3 CO2 + 4H2O

If you start with 10.0 molesof propane (C3H8), how manymoles of carbon dioxide will

be produced?

What’s the point of all this?

Key Point #1:Stoichiometry relates the amount of REACTANTS with the amount of PRODUCTS. It all relates back to the mole…

Scientists use stoichiometry to plan reactions! And guess what else is coming back….

TRAIN TRACKS!!!

Step 1: What to what?

Step 2: Write conversion factor(s)

Step 3: Train tracks

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…

Your turn! Whiteboards.

How many atoms are in 1.1 moles of C12H22O11?

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

Molar mass the amount of grams in the mole of a substance.

But Mr. J, how am I ever going to find out this information?

Molar Mass

1 mol C =

Molar Mass

1 mol C = 12 g C

Molar Mass

The atomic weight of an atom is also the molar mass of that atom.

Carbon has an atomic weight of 12.01.

In 1 mole of carbon, there are 12.01 grams.

In 1 mole of sodium, how many grams are there?

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?

Molar Mass

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

moles of CH4 do we have?

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?