1. Unit 3: Moles!!!

2. How BIG is a Mole??? What is a Mole?
Introduction to Project: How big is a Mole

3. How Big is a Mole - Example
A mole of un-popped popcorn would cover the US to what depth?
What is the area of the US?
Dimensional analysis of a mole to area; compare the two 

4. Finding the mass of one mole of an atom or molecule.
To find out how much one mole weighs for an atom, you can go to the periodic table and find that element’s ____________________________. This is also referred to as an element’s _________________________.
Atomic mass
Molar mass

5. Practice
What is the mass of one mole of copper? Answer: g What is the molar mass of lead? Answer: g

6. What about compounds?
Steps to finding the molar mass of a compound Step 1: List the elements in the compound and the number of atoms you have for each element. Step 2: Write the molar mass of each element and multiply it by the number of atoms. Step 3: Add the masses for each element to get the molar mass (Make sure you are following rules for sig figs)

7. Practice
Water Formula: H2O H: (2)(1.01)+ O:(1)(16.00) = g/mol Sodium Chloride Formula: NaCl Na: (1)(22.99)+ Cl:(1)(35.45) = g/mol

8. More Practice Sodium bicarbonate Formula: NaHCO3 Na: (1)(22.99)+
= g/mol
Sucrose
C12H22O11
C: (12)(12.01)+
H: (22)(1.01)+
O: (11)(16.00)
= g/mol

9. Can’t Just Stick Those on a Scale
What About Gases?
Can’t Just Stick Those on a Scale

10. Mole-Volume relationship
Volume of a Gas
Gases are difficult to weigh (mass)
The volume is effected by temperature and pressure
Gases must be compared at the same temperature and pressure when finding the amount of moles of gas we have

11. Standard Temperature and Pressure
STP
Standard Temperature and Pressure
00 and 1 atmosphere (atm) of pressure
At STP, 1 mole of any gas occupies 22.4 L
This is referred to as molar volume
1 mole = 22.4L of gas at STP

12. Molar Conversions
Write down your given and what you are trying to find
Cross out to get what you want
Use mole island (p.____ CRM)
Significant figures are determined by the given
Always include the substance formula and unit
(REMEMBER SIG FIGS)

13. Mole Island

14. Example How many moles of boron are in 25 g of boron? 25 g of B
= 2.3 mol of B
1 mol of B

15. Practice
How many moles of NaCl are in 100 g of NaCl?

16. More conversions
We now can go between mass (grams) and moles How do we go between moles and number of particles or vice versa? Remember that Avogadro’s number is the number of particles in a mole Therefore that will be our conversion factor 1 mol = 6.02 X atoms, molecules, or representative particles

17. Converting Number of Atoms to Moles
Magnesium is a light metal used in the manufacture of aircrafts, automobile wheels, tools, and garden furniture. How many moles of magnesium is 1.25 X 1023 atoms of magnesium?
KNOWNS:
# of atoms = 1.25 X 1023 atoms Mg
UNKNOWN:
Moles of Mg = ?
1.25 X 1023 atoms Mg
2.08 X 10-1 = mol Mg
1 mol Mg
6.02 X 1023 atoms Mg

18. Now you try
How many moles is 2.80 x 1024 atoms of silicon?

19. Your turn How many molecules are in 1.14 mol SO3 ?
How many moles are in 4.65 X 1024 molecules of NO2 ?

20. Examples What is the volume of 4.59 mole of CO2 gas at STP?
4.59 mol of CO L CO = 103 L of CO2
1 mol CO2

21. More Practice
How many moles is 5.67 L of O2 at STP?

22. What is the volume of 8.8 mol of CH4 gas at STP?