The MOLE

http://www.unit5.org/chemistry/Stoichiometry.html

Welcome to Mole Island

1 mole = 22.4 L @ STP(HONORS ONLY)

1 mol = molar mass

1 mol = 6.02 x 1023 particles

Counting Atoms

• Chemistry is a quantitative science - we need a "counting unit."

• The MOLEMOLE

• 1 mole is the amount of substance that contains as many particles (atoms or molecules) as there are in 12.0 g of C-12.

The Mole is DevelopedCarbon Atoms Hydrogen Atoms Mass Ratio

Number Mass (amu) Number Mass (amu) Mass carbon / Mass hydrogen

12

1

12 amu = 12

1 amu 1

24

[2 x 12]

2

[2 x 1]

24 amu = 12

2 amu 1

120

[10 x 12]

10

[10 x 1]

120 amu = 12

10 amu 1

600

[50 x 12]

50

[50 x 1]

600 amu = 12

50 amu 1

(6.02 x 1023) x (12)Avogadro’s number (6.02 x 1023) x (1)

(6.02 x 1023) x (12) = 12

(6.02 x 1023) x (1) 1

Avogadro’s number

AvogadroPaper

AvogadroPaper

Amadeo Avogadro (1776 – 1856)

1 mole = 602213673600000000000000

or 6.022 x 1023

thousandsmillionsbillionstrillions

quadrillions?

There is Avogadro's number of particles in a mole of any substance.

Particles in a MoleParticles in a Mole

Amedeo Avogadro (1766-1856) never knew his own number;

it was named in his honor by a French scientist in 1909.

its value was first estimated by Josef Loschmidt, an Austrian

chemistry teacher, in 1895.

Careers in Chemistry - Philosopher

Q: How much is a mole?A: A mole is a quantity used by chemists to count atoms and molecules. A mole of something is equal to 6.02 x 1023 “somethings.”

1 mole = 602 200 000 000 000 000 000 000

Q: Can you give me an example to put that number in perspective?A: A computer that can count 10,000,000 atoms per second would take 2,000,000,000 years to count 1 mole of a substance.

Counting to 1 Mole

Is that right? A computer counting 10 million atoms every secondwould need to count for 2 billion years to count just a single mole.

Lets look at the mathematics.

Therefore 1 year has 31,536,000 seconds or 3.1536 x 107 sec. A computer counting 10,000,000 atoms every second could count3.153 x 1014 atoms every year.

Finally, 6.02 x 1023 atoms divided by 3.1536 x 1014 atoms every yearequals 1,908,929,477 years or approximately 2 billion years!

x sec = 1 year 365 days1 year 1 day

24 hours 60 min1 hour

60 sec1 min

= 31,536,000 sec

How Big is a Mole?

One mole of marbles would cover the entire Earth (oceans included) for a depth of three miles.

One mole of $100 bills stacked one on top of another would reach from the Sun to Pluto and back 7.5 milliontimes.

It would take 9500 light years to travel from the bottom to the top of a stack of 1 mole of $1 bills.

1 Mole of Particles

The Mole

• A counting number (like a dozen)• = 6.02 x 1023 atoms or molecules

(called Avogadro’s number)• Important because it also is equal to the atomic

masses on the periodic table when given the unit of GRAMS. (Molar Mass or Formula Mass)

• To find molar mass, add the masses from the periodic table for all atoms in the compound. ROUND TO THE NEAREST WHOLE NUMBER!

Mole Map

Mole Island

Particle Peninsula

Mass Mountain

Mole Map

Mole IslandParticle Peninsula

1 mole = 6.022 x 1023 particles

(atoms or molecules)

How many molecules of water are there in a 125 mole sample?

23252

2 22

6.02 x 10 molecules H O125 moles H O x = 7.53 x 10 molecules H O

1 mole H O

Follow the Map to the solution!

How many molecules of carbon dioxide are there in a 3.65 mole sample?

Mole Map

Mole Island

Particle Peninsula

Mass Mountain

How many molecules of carbon dioxide are there in a 3.65 mole sample?

232

2

6.02 x 10 molecules COx

1 mole CO

23.65 mol CO

2422.19 x 10 molecules CO

Mole Island

Particle Peninsula

Try these

• How many moles of KBr are there in 2.56 x 1024 molecule sample?

• How many molecules of hydrogen gas will be in a 567 mole sample?

• How many particles of strontium oxide are in a 3.45 mole sample?

Mole Map

Mole Island

Particle Peninsula

Mass Mountain

Mole Map

Mole Island

Mass Mountain1 mole = molar mass (g)

How many moles are in 14.5 grams of Copper?

1 mole Cu14.5 grams Cu x = 0.228 moles Cu

63.5 g Cu

Follow the Map to the solution!

How grams of carbon dioxide are in a 3.65 mole sample?

Mole Map

Mole Island

Particle Peninsula

Mass Mountain

How grams of carbon dioxide are in a 3.65 mole sample?

2

2

44 g COx

1 mole CO23.65 mol CO 2 = 160 g CO

Mole Island

Mass Mountain

Try these

• How many grams of KBr are there in a 2.56 mole sample?

• How many moles of hydrogen (H2) gas will be in a 5.67 gram sample?

• How many moles of strontium oxide (SrO) are in a 345 gram sample?