1. The Mole
Beware the Mole!!
General Chemistry

2. Chemical Measurements
Everyday people perform jobs that require the ability to count and measure
Chef- essential to measure ingredients correctly
Construction worker- measuring cement, sand, gravel, and water determines the consistency of concrete
Painter- adding the right mixture of colors creates new colors.
With the mole, you’re doing the same math needed to convert $23 to cents, or pounds to tons, or centimeters to inches. It’s all called dimensional analysis.

3. Chemical Measurements
Dozen = 12
Baker’s dozen = 13
Gross= 144
Mole (mol) = 6.02x1023
A mole of water molecules has a volume of only 18 mL!
Molecules are unbelievably small, so a lot of them doesn’t take up that much space.
The mole is useful in chemistry because it links the microscopic world of atoms, molecules, and ions, to the macroscopic world
Can you imagine a mole of donuts?

4. Avogadro’s Number
6.02x1023 is so important in chemistry it’s given its own name…
You guessed it, Avogadro’s Number
In numerical form it looks like this:
602,000,000,000,000,000,000,000
A mole of paper would reach passed Pluto
A mole of basketballs is the size of Earth
A mole of rice would cover the land masses of Earth to a depth of 75 meters!

5. Scientific Notation Practice
Using the mole requires that we are comfortable using scientific notation
Write the following in scientific notation
Write the following in standard notation
6000
0.0067
78,000,000
698,700
6.00x103
6.70x10-3
7.80x107
6.99x105
9.00x10-6
9.01x10-3
6.02x104
9.03x109
7.77x10-2
9.21x10-7
60,200
9,030,000,000
0.0777

6. The mole
The mole establishes a relationship between the atomic mass and the gram
The mass in grams of 1 mole of a substance is equal to its atomic mass
6.02x1023 atoms Cu = g = 1 mol Cu
6.02x1023 atoms H = g = 1 mol H
6.02x1023 atoms Fe = g = 1 mol Fe

7. What’s in a Mole?
A mole of particles in an element is usually talking about atoms.
The number of molecules in a mole of any molecular compound is 6.02x1023

8. Molar Mass
The mass in grams of 1 mole of a substance is called the molar mass of the substance.
The molar mass of an element is equal to its atomic mass.
The unit for molar mass is grams per mole, or g/mol

9. Molar Mass Ne = 20.18 g/mol O2 = 16.00*2 = 32.00 g/mol
U = g/mol
NaOH = = g/mol
CO2 = *2 = g/mol
Al2(CO3)3 = 26.98*2 + (12.01*3) + (16.00*9) = g/mol

10. Moles to Grams Conversions
If you know the mass of a substance, you can calculate the number of moles.
You have 11.2 g of NaCl. How many moles is that?
1. determine the molar mass of NaCl (using the periodic table)
Na= 23.0 g/mol Cl= 35.5 g/mol
23.0 g/mol g/mol = 58.5 g/mol (get these #’s from the periodic table)

11. Unit Analysis Method Write down units asked for in answer to the right
Write down the given value over 1 on the left
Apply one or more unit factors to cancel units
It’s as easy as 1-2-3!

12. Moles to Grams Conversions
Molar mass of NaCl = 58.5 g/mol
Set up a conversion factor (a fraction whose value is equal to 1)
The units we need should be in the numerator and the units you already know in the denominator.

13. Moles to Grams Conversions
You can also determine the mass of a sample if you know the number of moles
2.50 mol of NaCl is how many grams?
Set up a conversion factor 

14. Moles to Grams Conversions
MASS
How many moles are in 14 g LiOH?
How many moles are in 15 g N2?
g x mol = moles g
Molar Mass
moles x g = g mol
MOLES
14 g LiOH 1
1 mol LiOH
23.95 g LiOH
0.58 mol LiOH
15 g N2 1
1 mol N2
28.02 g N2
0.54 mol N2

15. Moles to Grams Conversions
How many grams are in 4 mol H2O2?
How many grams are in 56 mol CaCO3?
4 mol H2O2 1
g H2O2
1 mol H2O2
g H2O2
56 mol CaCO3 1
g CaCO3
1 mol CaCO3
g CaCO3

16. Moles to Molecules
Molecules OR atoms
The number of particles in 1 mole of any substance is always the same- Avogadro’s number. or
How many atoms are in 3 mol of elemental Ne?
6.02x1023 particles
1 mol
1 mol
6.02x1023 particles
3 mol Ne 1
6.02x1023 atoms
1 mol
1.81x1024 atoms Ne

17. Moles to Molecules (cont.)
PARTICLES
How many atoms of oxygen are in 6 mol of O2 molecules?
How many moles of I2are in 8.02x1020 molecules of I2?
Atoms Molecules?
Use the subscript
6.02x1023 particles
1 mol
Avogadro’s Number
1 mol
6.02x1023 particles
MOLES
6 mol O2 1
6.02x1023 molecules O2
1 mol O2
2 atoms O
1 molec. O2
7.22x1024 atoms O
1 mol I2
6.02x1023 molecules I2
8.02x1020 molec. I2 1
1.33x10-3 mol I2

18. Multistep Conversions
You want to impress your date by boasting you know how many molecules of table sugar are in the cake you just made. You need 250 g of sugar (C12H22O11). How many sucrose molecules will be in the cake?
Plan: Convert the mass to moles using the molar mass and then convert to moles using Avogadro’s number.
MASS
PARTICLES
Avogadro’s Number
Use molar mass
MOLES
250 g C12H22O11 1
1 mol C12H22O11
342.3 g C12H22O11
6.02x1023 molecules
1 mol C12H22O11
4.4x1023 molec. C12H22O11

19. Multistep Conversions
If you burned 4.0x1024 molecules of methane (CH4) during a laboratory experiment, what mass of methane did you use?
Plan: Convert your given # of molecules to moles using Avogadro’s number, then convert the moles to grams using the molar mass of methane. ( *4)
4.0 x 1024 molec. CH4 1
1 mol CH4
6.02x1023 molec. CH4
g CH4
1 mol CH4
g CH4