1. Chapter 10: Chemical Quantities
The Mole

2. What is Avogadro’s Number?
What is a mole?
The SI unit that represents the amount of a substance that contains 6.02 x 1023 representative particles of that substance.
What is Avogadro’s Number?
The number of particles contained in one mole of a substance.
6.02 x 1023 particles
602,000,000,000,000,000,000,000

3. What is a Representative Particle?
Atom:
The smallest particle of an element
Molecule:
Group of atoms joined together by covalent bonds
Formula unit:
Lowest ratio of elements in ionic bonds
Particle:
This word can be used for any of the above words

4. Atomic or Formula Mass
Mass of one single representative particle of a substance
Measured in atomic mass units (amu)

5. C 12.01 amu NaCl 22.99 amu + 35.45 amu = 58.44 amu H2O
How do you find Atomic or Formula Mass?
Add up the amu for every part of the substance:
Find the amu on the Periodic Table C
12.01 amu
NaCl
22.99 amu amu = amu
H2O
(1.01 amu x 2) amu =
18.02 amu

6. Molar Mass C 12.01 amu = 12.01 g/mol NaCl 58.44 amu = 58.44 g/mol H2O
The mass of one mole of any substance
Measured in grams/ mole
Same as finding atomic mass, but change amu to grams. C
12.01 amu = g/mol
NaCl
58.44 amu = g/mol
H2O
18.02 amu = g/mol

7. Converting # of Particles to # of Moles
Formula:
1 mole
6.02 x 1023 particles
# of moles =
# of particles x

8. Sample Problem:
How many moles of NaCl are in 3.01x1023 formula units of NaCl?

9. Converting # of Moles to # of Particles
Formula:
6.02 x 1023 particles
1 mole
# of particles =
# of moles x

10. Sample Problem:
How many particles are in 3 moles of water?

11. Converting # of Moles to Mass
Formula:
Molar mass (g)
1 mole
Mass (g) =
# of moles x

12. Sample Problem:
What is the mass of 1 mole of LiOH?

13. Converting Mass to # of Moles
Formula:
1 mole
Mass (g)
# of moles =
Mass (g) x

14. Sample Problem:
How many moles of NaCl are in grams of NaCl?

15. Mole-Volume Relationship
Avogadro’s Hypothesis:
At standard temperature and pressure (STP) 1 mole of any gas occupies the same volume.
STP: 0oC and 1 atm

16. At STP, 1 mole or 6.02 x 1023 particles, of ANY gas, has a volume of 22.4 L.
22.4 L is called the molar volume of a gas.

17. Converting # of Moles of gas to Volume
Formula:
22.4 L
1 mole
Volume of gas =
moles of gas x

18. Sample Problem:
What is the volume, in liters, of 0.60 mol of SO2 gas at STP?

19. Converting Volume of gas to Moles
Formula:
1 mole
22.4 L
Moles of gas =
volume of gas x

20. Sample Problem:
If you collect 8.00 L of O2 gas, how many moles have you collected?

21. Calculating Molar Mass from Density
Formula:
grams
mole
grams L
22.4 L
1 mole =
Density
Molar mass

22. Sample Problem:
What is molar mass of a gas with a density of 2.86 g/L at STP?

23. Percent Composition of a Substance
Mass of element in the compound x
Molar Mass of Compound

24. Sample Problem
 Find the % composition of H and O in water