1. The Mole What's a mole? In chemistry, a mole is a counting unit.
What does that mean?
1 dozen = 12 units(ie eggs,donuts)
1 mole = 6.02x1023 particles.
That's 602,000,000,000,000,000,000,000 particles!
6.02x1023 is Avogadro's Number
A mole is used to represent lots of particles
atoms
molecules(covalent compounds)
ions
Forumula Units (ionic compounds) 1

2. The Mole If you have 3 particles of water, what do you have?
You have 3 water molecules because H2O is molecular
Covalently bonded compounds are called molecules
If you have 4 particles of table salt, what do you have?
You have 4 NaCl formula units becauseNaCl is ionic
Ionic compounds are called formula units
If you have 5 particles of gold, what do you have?
You have 5 gold atoms because gold is an element
Atoms are the unit for elements 2

3. The Mole How do you represent 6.02x1023 in a scientific calculator?
You can type 6.02x10^23 if you want...
but there's a better way!
- For graphing calculators:
Type in 6.02 then the 2nd button, then the “,” button, then 23
The calculator will display 6.02E23
This means “6.02x1023” to the calculator.
- For other calculators there is usually a key marked “E” or “EXP” that allows you to enter numbers in scientific notation. 3

4. How BIG is Avagadro's Number?
6.02x1023 dollars would be enough to give every person on Earth $87 trillion. That’s $1 million a second for the next 2.8 years.
A modern computer that can make up to 100 million counts per second would take almost 200 million years to count to 6.02x1023
If 6.02x1023 snowflakes fell evenly across the United States, the blanket of snow would cover every building in the country, including the tallest skyscrapers.
If you could travel at the speed of light (186,000 mi/s in a vacuum), it would take you more than 100 billion years (longer than the Universe has been around) to travel 6.02x1023 miles. 4

5. Moles & Particles
If 1 mole = 6.02 x 1023, then we can determine how many atoms(or molecules) are in stuff.
1 mole : 6.02 x 1023
Or 1 mol
6.02 x 1023 particles
How many silver atoms are in 3 moles of Ag?
(using dimensional analysis (factor method))
3 mol Ag x 6.02 x 1023 atoms Ag =
1mol Ag
Waitaminute… but why are moles on the bottom and Avogadro’s number on the top?
Since 1mol = 6.02x1023, either one can be on top, we just choose the one that will cancel out the original unit. 5

6. Mole to Particle Conversions
Examples:
How many molecules of methane are in 4.50 mol of methane?
4.50 mol CH4 x
6.02x1023 molecules CH4
1 mol CH4
= 2.71x1024 molecules CH4
How many moles of iron are in 2.39x1024 iron atoms?
1 mol Fe = 6.02x1023 Fe atoms
2.39x1024 atoms Fe x
1 mol Fe
6.02x1023 atoms Fe
= 3.97 mol Fe 6

7. Molar Mass Atomic measures the mass of atoms Really small!
Atomic Mass is based on Carbon-12 (12C)
Very abundant, bonds with most everything
1 amu = 1/12 the mass of 12C
Too small to count
Scientists decided that if 12C = 12 amu, then 12 grams of carbon = 1 mole of carbon.
Which is equal to 6.02x1023 atoms of carbon
1 mole of anything = its atomic mass in grams
1 atom of oxygen = amu
1 molecule of H2O = amu
1 formula unit of NaCl = 58.44amu
1 mole of oxygen = grams
1 mole of H2O = grams
1 mole of NaCl = grams 7

8. Moles & Particles
Molar Mass = the mass in grams of 1 mole of any substance.
AKA gram-formula mass
Unique for every substance
Unit: grams per mole (g/mol)
Calculations with Molar Mass
What is the mass in grams of 2 mole of iron?
molar mass of Fe = g/mol
2 mol Fe x grams Fe = grams Fe
1 mol Fe 8

9. Mole/Mass Calculations
Examples:
1. What is the mass of moles of magnesium?
Using Periodic Table: 1 mol Mg = 24.31g Mg
2. What is the mass of 5.80 moles of carbon monoxide? Molar mass of CO = 28.01g/mol
g Mg
= 6.08 g Mg
0.250 mol Mg x
1 mol Mg
28.01 g CO
= 162 g CO
5.80 mol CO x
1 mol CO 9

10. Mole/Mass Calculations
Examples:
1. How many moles would grams of neon be equal to? 1 mol Ne = 20.18g Ne
2. How many moles would grams of methane(CH4) be equal to? Molar mass of methane = g/mol
1 mol Ne
= mol Ne
50.45g Ne x
20.18g Ne
1 mol CH4
= mol CH4
134.0g CH4 x
16.05g CH4 10