1. Counting Atoms How many atoms are in: NaCl? H2O? MgSO4? Pb(SO4)2?
We can’t actually count atoms in chemistry! b/c they are too small!!
So what can we count??

2. Molar Mass of Compounds
Molar Mass = the sum of the masses of each element if we had 1 mole
Ex: CO2
Carbon has a MM of 12.01g/mole
Oxygen has a MM of 16.00g/mole
Molar mass of CO2 is
C =1 x 12.01=
O =2 x 16.00= 32.00
44.01g/mole

3. Molar Mass Find the Molar Masses of the following compounds. Water
Sodium chloride (Salt)
Sodium bicarbonate (Baking Soda)
Glucose

4. Water
Sodium chloride (Salt)

5. Sodium bicarbonate (Baking Soda)
4. Glucose

6. Representative Particles
Type of Substance
Description
R.P. ( UNIT)
Element
1 symbol
ATOM
Covalent Compound
2 or more
Non-metals
MOLECULE
Ionic Compound
Metal (or NH4) and a non-metal
FORMULA UNIT

7. Caribbean Monkeys Eat Avocados In Forest
Caribbean = Covalent Monkeys = Molecules

8. Caribbean Monkeys Eat Avocados In Forest
Eat = Element Avocados = Atoms

9. Caribbean Monkeys Eat Avocados In Forest
In = Ionic Forest = Formula Unit

10. Determine the type of Representative Particle
1. Mg
2. C3H8
3.NaCl
4. CBr4
5. Li
6. K2O
7. Cl2
8. H2O

11. Welcome to St. Mole Islands!!!

13. To go anywhere on the mole islands you must go thru the mole!!!
1 mole = 6.02 x 1023 atom or
1 mole = 6.02 x 1023 molecule
1 mole = 6.02 x 1023 formula unit

16. Using Representative Particles
Example Problems
Using Representative Particles

17. How many moles of magnesium is 1.25 x 1023 atoms?
Given:
Conversions:
Work:
Want?
Answer:

18. How many moles of magnesium is 1.25 x 1023 atoms?
Given Info:
Conversions:
Work:
Want?
Answer:

19. How many molecules are in 2.12 mole of propane-C3H8 ?
Given Info:
Conversions:
Work:
Looking for?
Answer:

20. How many molecules are in 2.12 mole of propane-C3H8 ?
Given Info:
2.12 mole C3H8
Conversions:
1 mole = 6.02x1023
molecule
Work:
2.12 mole x 1023 molecule
C3H C3H8
1 mole C3H8
Want? molecules C3H8
Answer: x 1024 molecule C3H8

21. Example Problems
Using Molar Mass

23. How many grams are in 2 moles of calcium hydroxide?
Given Info:
Conversions:
Work:
Want?
Answer:

24. How many molecules are in 4.42 x 106g of water molecules?
Given Info:
Conversions:
Work:
Want?
Answer

26. How many molecules are in 4.42 x 106g of water molecules?
Given Info:
4.42 x 106g
Conversions:
MM = 18.02g H2O
1 mole
1mole = 6.02x1023
molecule
Work:
4.42x106g 1 mole x1023 molecules
H2O H2O H2O
18.02 g mole H2O
H2O
Looking for?
molecules
Answer: x 1029 molecules

27. Example Problems
Using Molar Volume

28. Molar Volume @ STP only Standard Temperature and Pressure: STP
Standard Temperature: 273K
Standard Pressure: 1 atmosphere (atm)
At these 2 conditions: Molar Volume
1 mole = 22.4L

30. How many liters are 2.78 x 1031 molecules?
Given Info:
Conversions:
Work:
Want?
Answer:
How many liters are 2.78 x 1031 molecules?

31. How many liters are 2.78 x 1031 molecules?
Given Info:
2.78 x 1031 molecules
Conversions:
1 mole =6.02x1023 molecules
Work:
2.78 x1031 molecules 1 mole L
6.02 x mole
molecules
Want?
liters
Answer: 1.03 x 109 L
How many liters are 2.78 x 1031 molecules?

32. The density of a gaseous compound containing carbon and oxygen is 1
The density of a gaseous compound containing carbon and oxygen is STP. Determine the molar mass of the compound.
Given Info:
Conversions:
Work:
Want?
Answer:

33. The density of a gaseous compound containing carbon and oxygen is 1
The density of a gaseous compound containing carbon and oxygen is STP. Determine the molar mass of the compound.
Given Info:
Conversions:
Work:
Want?
Answer: