1. Chapter 10 The Mole

2. The Mole: A Unit of Measure
First, let’s look at a more familiar unit of measure: “dozen”
1 dozen = 12
1 dozen eggs = 12 eggs
1 dozen atoms = 12 atoms
1 dozen NaCl molecules = 12 NaCl molecules

3. Let’s try another familiar unit
1 dozen apples = 12 apples
1dozen apples = 2.0kg
I dozen apples = 0.20bushel
What is the mass of 90 average sized apples if one dozen apples has a mass of 2.0kg?

4. Calculations
How many Toll House Chocolate Chip cookies will one bag of Nestle chocolate chips produce?
“One bag of chocolate chips = 12 oz.”
“12 oz of chocolate chips = 2 cups”
“2 cups will provide 5 dozen cookies”
“1 dozen = 12 cookies”

5. Chocolate Chip Cookies
How many Toll House Chocolate Chip cookies will one bag of Nestle chocolate chips produce?
One bag of chocolate chips = 12 oz.
12 oz of chocolate chips = 2 cups
2 cups will provide 5 dozen cookies
1 dozen = 12 cookies
1 bag x
12 oz. x
1 bag
2 cups x
12 oz.
5 dozen
2 cups
x 12 cookies =
1 dozen
60 cookies

6. Units of Measure
1 mole = 602,000,000,000,000,000,000,000 (or x 1023)
1 mole of eggs = 6.02 x 1023 eggs
1 mole of atoms = 6.02 x 1023 atoms
1 mole of H2O molecules = 6.02 x 1023 H2O molecules

7. Why use the mole? For easier calculations
To compare the masses of different elements and compounds
To predict how much of a product you will get from reactants in a chemical reaction

8. The Mole
The number of representative particles in a mole is 6.02 X1023
It is also called Avogadro’s number
Representative Particles
Ionic compounds – Formula units
Covalent (molecular compounds) – molecules
Elements- atoms

9. Example
Magnesium is a light metal used in manufacture of aircraft, automobile wheels, tools, and garden furniture. How many moles of magnesium is 1.25 X 1023 atoms of magnesium?

10. Converting moles to number of atoms
Propane is a gas used for cooking and heating. How many atoms are in mol of propane (C3H8)?

11. Molar Mass To calculate the molar mass of a substance:
1. Find the mass of each element
2. Multiply the mass by the number of atoms present in the compound
3. Then add the total masses of each element together

12. Molar Mass Example
Glucose (C6H12O6)
H2O

13. The Mole- Mass Relationship
Use the molar mass of a substance to convert between mass and moles

14. Example
The aluminum satellite dishes are resistant to corrosion because the aluminum reacts with oxygen in the air to forma coating of aluminum oxide. This tough resistant coating prevents any further corrosion. What mass of 9.45 mol of aluminum oxide?

15. Converting Mass to Moles example
When iron is exposed to air, it corrodes to form red-brown rust. Rust is Iron (III) oxide. How many mole of iron(III) oxide are contained in 92.2 g of pure Fe2O3 ?

16. The Mole-Volume Relationship
Avogadro’s hypothesis states that equal volumes of gases at the same temperature and pressure contain equal number of particles.
Standard temperature and pressure

17. Mole to Volume Relationship
STP (Standard temperature and pressure)
0 degrees Celsius
101.3kPa or 1atm
At STP, 1 mol or 6.02X 1023 representative particles of any gas occupies a volume of 22.4L
The quantity 22.4 L is called the molar volume of a gas

18. Example

19. Calculating Molar Mass from Molar Density
Molar mass= STP X Molar STP

20. Example

21. The mole road map