1. The Mole (466)

2. The Mole A mole is a number (like a dozen means 12).
Having this number of atoms allows us to easily convert atomic masses to molar masses.
The abbreviation for 1 mole is 1 mol
6.02 x 1023 is a “mole” or “Avogadro’s number”
1 mol = 6.02 x 1023 molecules (or atoms)

3. Molar mass The mass of one mole is called “molar mass”
E.g. 1 mol Li = 6.94 g/mol of Li
(Use your periodic table) What are the following molar masses?
S SO2
Cu3(BO3)2
32.06 g/mol
64.06 g/mol
g/mol
Cu x 3 = x 3 =
B x 2 = x 2 =
O x 6 = x 6 =
308.27

4. Converting between grams and moles
If we are given the # of grams of a compound we can determine the # of moles, & vise-versa
In order to convert from one to the other you must first calculate molar mass
mols(n)= amount in grams (m)
molar mass (MM)
n = m/ MM
m= g/mol x mol
0.25
HCl
53.15
H2SO4
3.55
NaCl
1.27 Cu
Equation
mol (n)
mass MM
Formula
36.46
9.1
98.08
0.5419
mol= m  g/mol
58.44
207
m= g/mol x mol
63.55
0.0200
mol= m  g/mol

5. DID YOU KNOW!
Watermelons stored at room temperature (21 degrees Celsius) are richer in nutrients than refrigerated ones.
By letting your watermelons ripen outside the fridge, you are also allowing them to gain lycopene and beta-carotene, both of which are important nutrients.
Lycopene, an antioxidant, has been linked to reducing the risk of several diseases such as prostate cancer, and lowering inflammation that may cause hypertension and heart disease.

6. Making Molar Solutions
From Solids
466

7. What are molar solutions?
A molar solution is one that expresses “concentration” in moles per volume
Molarity = # of mols  volume of solution(L)
M = n V
Usually the units of M are in mol/L
L refers to entire volume, not just the
water!

8. Calculations with molar solutions
Q: How many moles of NaCl are required to make 7.5 L of a 0.10 M solution?
M= n/V
# mol NaCl =
7.5 L
x 0.10 mol NaCl
1 L
= 0.75 mol

9. Practice Problems 63 g a) 22 g b) 1.75 g a) 0.041 mol/L b) 0.054 mol/L
1. How many grams of nitric acid are present in 1.0 L of a 1.0 M HNO3 solution?
2. Calculate the # of grams needed to produce each:
a) 0.20 L of 1.5 M KCl
b) L of M HCl
3. Give the molarity of a solution containing 10 g of each solute in 2.5 L of solution:
a)H2SO4
b)Ca(OH)2
63 g
a) 22 g
b) 1.75 g
a) mol/L
b) mol/L