Use the train track method to work the following problems:

1. How many eggs are in 17.5 dozens?

2. How many cases would 200 cokes occupy?

(1 case = 24 cokes)

• ONLY WRITE DOWN UNDERLINED WORDS IN YOUR NOTES

Words that represent numbers• Pair = 2

• Couple = 2

• Dozen = 12

• Baker’s dozen = 13

• Gross = 144

Professions that have units• Baker – 1 dozen = 12 items

• Paper manufacturer – 1 ream = 500 sheets

• Farmer – 1 gross = 144 items

• Coca Cola distributor – 1 case = 24 items

1 Mole (symbolized mol)= 602,000,000,000,000,000,000,000 or 6.02 X 1023 particlesor 6.02 E 23

aka: avogadro’s number

The Chemist’s unit…

It’s a big number…One mole of marbles would cover the entire Earth (oceans included) for a depth of three miles.

One mole of basketballs would fill a bag the size of the earth.

One mole of pennies would cover the earth to a depth of 400 meters.

It’s a big number…• A mole of coke

cans is enough to cover the surface of the earth to a depth of over 200 miles!

• If you connected paper clips at 1 million paper clips per second, it would take you 190 million centuries to finish stringing one mole of paper clips together!

Your paper clip chain of 1 mole of clips could circle the earth 400 trillion times!

What would happen if a mole of H2O molecules rushed into this room

right now?

Could you swim in them?

• 1 mole of water is 18 mL of water…it’s hardly a puddle

• Because particles are so small, moles are a very convenient unit to use in chemistry

Lets talk ‘particles’Atom – anything on the periodic tableIon – anything that is chargedMolecule – name for a covalent compoundFormula Unit – name for an ionic compound

What type of particle am I?

• CH4

• Copper(II) sulfate

• H2

• Au• Au+

• nitrite

• Molecule• Formula unit• Molecule• Atom• Ion• ion

Molar Mass

• Is the mass of a mole• For elements, one mole equals the

atomic mass in grams• 1 mole C atoms = 12.011 grams• 1 mole Cu atoms = ?

• 1 mole of H2O molecules = ?

a.k.a•Molecular mass (MM) •Molecular weight (MW) •Formula mass (FM) •Formula weight (FW)•Gram formula mass (GFM) !!!!

H2O• Let’s break it down• 1 mol of H = 1 g• How many do we have?• 2 mol of H = 2 X 1 g = 2 g• 1 mol of O = 16 g• Add ‘em up:

• Molar mass of water = 2 g + 16 g = 18 g

Back to formulas…

Na2SO4

Na2SO4• Name it!!!• Sodium sulfate• Calculate its gfm• 142.042 g/mol (did you get the units right?)• How many atoms of

sodium would I need to make one formula unit of sodium sulfate?

Na2SO4

• How many atoms of sodium are needed to make one formula unit of sodium sulfate?

• 2

Na2SO4

• How many dozens of sodium atoms are needed to make one dozen formula units of sodium sulfate?

• 2

Na2SO4

• How many moles of sodium atoms are needed to make one mole of sodium sulfate?

• 2

Creating mole-to-mole links using formulas

• 1 mole of Na2SO4 = 2 moles of Na

• 1 mole of Na2SO4 = 4 moles of O

• 1 mole of Na2SO4 = 1 mole of S

• 1 mole of Na2SO4 = 1 mole of SO42-

• 1 mole of Na2SO4 = 2 moles of Na+

• NOTE from now on: (number) (unit) (chemical)• Unit can be mass, mole, particle

6.02E23 f.u.’s Na2SO4 = 1 mole Na2SO4

How many f.u.’s of sodium sulfate are in 1 mole of sodium sulfate?

142.042 g Na2SO4 = 1 mole Na2SO4

How many grams of sodium sulfate are in 1 mole of sodium sulfate?

Rule: 1 always goes with the mole

• Now we can use these as links in dimensional analysis.

• How many formula units of sodium sulfate are in 10 moles of sodium sulfate?

• Start with the set-up we used for dimensional analysis:

Now finish the problem…you already wrote the next link down…

A more interesting problem…• How many oxygen atoms are needed to make 7

moles of sodium sulfate?

• Start with the set-up we always use in dimensional analysis

• NOTE: chemicals are not the same, so we use 3 step process:

• 1. find moles of given

• 2. make conversion factor to convert to moles of desired chemical

• 3. Find desired units

1. Find moles of given

• We already have moles of sodium sulfate, so we’re done with this step

2. Make conversion factor to convert to moles of desired chemical

• We have moles of sodium sulfate, we want moles of oxygen

• There are 4 moles of oxygen in 1 mole of sodium sulfate, so…

3. Find desired units

• We have moles of oxygen, but we want atoms

• 1 mole of oxygen has 6.02E23 atoms of oxygen, so…

Reminder

• What’s the link between mass and moles?– Molar mass

• What’s the link between particles and moles?– Avogadro’s number

Another problem…• How many moles of sulfate ions are needed to make

3.1 grams of sodium sulfate?

• Work it! Ask your group if you need help.

Reminder

• What’s the link between mass and moles?– Molar mass

• What’s the link between particles and moles?– Avogadro’s number

Another problem…• How many grams of sodium are needed to make

1 x 1015 f.u.’s of sodium sulfate?

• Work it! Ask your group if you need help.

Reminder

• What’s the link between mass and moles?– Molar mass

• What’s the link between particles and moles?– Avogadro’s number