1. The Mole
Chapter 10

2. What is a Mole?
A unit that is a specified number of particles (atom, molecule, ion, or formula unit)
Avogadro’s Number: x representative particles.

3. Just How Big is a Mole?
Enough soft drink cans to cover the surface of the earth to a depth of over 200 miles.
If you had Avogadro's number of unpopped popcorn kernels, and spread them across the United States of America, the country would be covered in popcorn to a depth of over 9 miles.
If we were able to count atoms at the rate of 10 million per second, it would take about 2 billion years to count the atoms in one mole.

4. Three types of conversions with the Mole
Mole Representative Particles
Mole Mass
Mole Volume at STP

5. This is your task and you have to do it…
You must find in your textbook the three conversion factors we are going to be using to convert back and forth.

8. The Mole 1 dozen cookies = 12 cookies
1 mole of cookies = 6.02 X 1023 cookies
1 dozen cars = 12 cars
1 mole of cars = 6.02 X 1023 cars
1 dozen Al atoms = 12 Al atoms
1 mole of Al atoms = 6.02 X 1023 atoms
Note that the NUMBER is always the same, but the MASS is very different!

9. A Mole of Particles Contains 6.02 x 1023 particles
= x 1023 C atoms
= x 1023 H2O molecules
= x 1023 NaCl “molecules”
(technically, ionics are compounds not molecules so they are called formula units)
6.02 x 1023 Na+ ions and
6.02 x 1023 Cl– ions
1 mole C
1 mole H2O
1 mole NaCl

10. Avogadro’s Number as Conversion Factor
6.02 x 1023 particles
1 mole or
1 mole
Note that a particle could be an atom OR a molecule!

11. Example 1- Number of Particles and Moles
How many moles of magnesium is x 1023 atoms of magnesium?
0.208 mol Mg

12. Example 2- Number of Particles and Moles
How many moles is 2.80 x atoms of silicon?
4.65 moles of Silicon

13. Converting Moles to Molar Mass
To convert from moles to mass or mass to moles you must find molar mass (mass of a mole)
Units used for molar mass: atomic mass units (amu)
The molar mass of an element is found on the periodic table
The molar mass of a compound you must solve (hahaha and if your writing this, sucka’)

14. Molar Mass of Molecules and Compounds
1 mole of CaCl2 = ?
1 mole Ca x 40.1 g/mol
+ 2 moles Cl x 35.5 g/mol
= g/mol CaCl2

15. Example- Molar Mass
Prozac, C17H18F3NO, is a widely used antidepressant that inhibits the uptake of serotonin by the brain. Find its molar mass.

16. Calculations with Molar Mass
Grams Moles

17. Converting Moles and Grams
Aluminum is often used for the structure of light-weight bicycle frames. How many grams of Al are in 3.00 moles of Al?
3.00 moles Al ? g Al

18. 1. Molar mass of Al 1 mole Al = 27.0 g Al
2. Conversion factors for Al
27.0g Al or mol Al
1 mol Al g Al
3. Setup 3.00 moles Al x g Al
1 mole Al
Answer = g Al

19. Example- Moles to Mass
The artificial sweetener aspartame (Nutra-Sweet) formula C14H18N2O5 is used to sweeten diet foods, coffee and soft drinks. How many moles of aspartame are present in 225 g of aspartame?
.765 moles of aspartame

20. Mole-Volume Relationship
Volume of gas varies with changes in temperature and changes in pressure.
Due to these variations, the volume of a gas is measure at Standard Temperature and pressure (STP).
Temperature 0˚C
Pressure kPa or 1 atmosphere (atm)

21. Conversion Factor

22. Example
Sulfur dioxide is a gas produced by burning coal. Determine the volume, in liters of mole SO2 gas at STP.
13.44 L

23. Example
At STP, what volume is occupied by each of the following gases?
6.7 mol H2
2.56 mol CH4
1.5 x 10^2 or 150 L H2
5.73 x 10^1 or 57.3 L CH4

24. Atoms/Molecules and Grams
Since 6.02 X 1023 particles = 1 mole AND 1 mole = molar mass (grams)
You can convert atoms/molecules to moles and then moles to grams! (Two step process)
You can’t go directly from atoms to grams!!!! You MUST go thru MOLES.
That’s like asking 2 dozen cookies weigh how many ounces if 1 cookie weighs 4 oz? You have to convert to dozen first!

25. Everything must go through Moles!!!
Calculations
molar mass Avogadro’s number Grams Moles particles
Everything must go through Moles!!!

26. Atoms/Molecules and Grams
How many atoms of Cu are present in g of Cu?
35.4 g Cu mol Cu X 1023 atoms Cu g Cu mol Cu
= 3.4 X 1023 atoms Cu

27. Learning Check!
How many atoms of K are present in 78.4 g of K?

28. Learning Check!
What is the mass (in grams) of 1.20 X molecules of glucose (C6H12O6)?

29. Learning Check! How many atoms of O are present in 78.1 g of oxygen?
78.1 g O2 1 mol O X 1023 molecules O2 2 atoms O g O mol O molecule O2

30. Stoichiometry!!!
The calculation of quantities in chemical reactions
We will use balanced chemical equations to calculate how much reactant is needed or how much product is produced in a reaction.

31. Writing and Using Molar Ratios
Use molar ratios as a new conversion factor to convert between a given number of moles of a reactant or product to moles of a different reactant or product.
It is made from the coefficients of a balanced chemical equation interpreted in terms of moles.

32. Example 1
How many grams of NH3 are produced when 0.60 moles of nitrogen reacts with hydrogen? N2 + H2  NH3

33. Example 2
How many atoms of aluminum are needed to form 3.7 moles Al2O3? Al + O2  Al2O3

34. Example 3
What volume (L) of oxygen are required to react completely with 14.8 moles Al? 4Al + 3O2  2Al2O3

35. Example 4
How many grams of Al2O3 are formed when 0.78 mol O2 reacts with aluminum? 4Al + 3O2  2Al2O3

36. Example 5
Iron (III) oxide reacts with carbon monoxide to yield iron and carbon dioxide in the following reaction: Fe2O3 + 3CO  2Fe + 3CO2 How many atoms of Fe are produced from 1.8 mol of Fe2O3?

37. Limiting/ Excess Reagent
In a chemical reaction, the reactant that determines the amount of product that can be formed by a reaction is the limiting reagent.
The reactant that is not completely used up in a reaction is called the excess reagent.

38. How to find limiting Reagent
Approach 2: Find the limiting reagent by calculating and comparing the amount of product each reactant will produce.
Balance the chemical equation
Convert the given information into moles (if necessary).
Use stoichiometry for each individual reactant to find the mass of product produced.
The reactant that produces a lesser amount of product is the limiting reagent.
The reactant that produces a larger amount of product is the excess reagent.
To find the amount of remaining excess reactant, subtract the mass of excess reagent consumed from the total mass of excess reagent given.

39. Example 1 C6H12O6+6O2→6CO2+6H2O+energy
Consider respiration, one of the most common chemical reactions on earth.
C6H12O6+6O2→6CO2+6H2O+energy
What is the limiting reagent in the reaction of 25 grams of glucose
with 40 grams of oxygen?

40. Example 2
What is the limiting reagent if 2.40 g Mg reacts with 10.0 g O2?
Mg+O2→MgO

41. Example 3 4C2H3Br3+11O2→8CO2+6H2O+6Br2
What is the limiting reagent if 76.4 grams of C2H3Br3 were reacted with
49.1 grams of O2?
4C2H3Br3+11O2→8CO2+6H2O+6Br2

42. Example 4
How much the excess reagent remains if 24.5 grams of CoO is
reacted with 2.58 grams of O2?
4CoO+O2→2Co2O3

43. Percent Yield = 𝐴𝑐𝑡𝑢𝑎𝑙 𝑌𝑖𝑒𝑙𝑑 𝑇ℎ𝑒𝑜𝑟𝑒𝑡𝑖𝑐𝑎𝑙 𝑌𝑖𝑒𝑙𝑑 x 100
The ratio of the actual yield to the theoretical yield expressed as a percent.
Actual yield- the amount of product that actually forms when the reaction is carried out in the lab.
Theoretical yield- the maximum amount of product that could be formed from given amounts of reactants.
Percent Yield = 𝐴𝑐𝑡𝑢𝑎𝑙 𝑌𝑖𝑒𝑙𝑑 𝑇ℎ𝑒𝑜𝑟𝑒𝑡𝑖𝑐𝑎𝑙 𝑌𝑖𝑒𝑙𝑑 x 100

44. Example 1
What is the percent yield if 13.1 grams CaO is actually produced when 24.8 g CaCO3 is heated? CaCO3  CaO + CO2