1. How is the mole concept related to chemical formulas?
Chapter 8- The Mole
How is the mole concept related to chemical formulas?

2. The “Mole”
We are not talking about this mole…..

3. The “Mole”
……and we are not talking about this kind of mole……

4. The “Mole”
WE ARE TALKING ABOUT THIS KIND OF MOLE!!

5. What is a mole? Avogadro's mole: The amount of a substance
Tells us how much of “stuff” is in a given amount
Avogadro's mole:
1 mole= 6.02 x 1023 atom, ions, or molecules
1 mole of carbon = g

6. Volume Island Atom Island Mass Island Mole Island (g)
(# moles) x (6.02x1023 atoms)
(molar mass) / (# moles)
Atom Island
Mass Island
(g)
Mole Island
(# atoms) / (6.02x1023 atoms)
(# moles) / (molar mass)

7. Practice problems Determine the mass in grams, of 3.50 mole of copper
How many atoms of O2 are there in 2.86 moles?
How many atoms are in g of silicon?
Determine the number of moles in the following elements:
0.345 g chlorine
184.2 g of sodium
0.320 g copper
282.4 g of iron

8. Practice Problem Answers
grams
1.72 x 1024 atoms
6.02 x 1023 atoms
moles of chlorine
8.010 moles of sodium
moles of copper
5.057 moles of iron

9. Relative Atomic Mass and the Periodic Table
Proton amu
Neutron amu
Electron amu

10. Relative Atomic Mass and the Periodic Table
Sodium: 11 protons ( ) = amu
11 electrons ( ) = amu
12 neutrons ( ) = amu
Total mass = … amu
Why is this different from the periodic table??
Take into account, isotopes
Periodic table displays *relative atomic mass*
Atomic masses will never be whole numbers

11. Calculating Relative Atomic Mass
The mass of copper-63 atom is amu and that of a copper-65 atom is amu. Using this data and the abundance of these two isotopes, determine the average atomic mass of native copper. The abundance of copper-63 is 69.17%. The abundance of copper-65 is 30.83%.

12. Answer
(62.94 x ) + (64.93 x ) = amu copper-63 copper-65

13. Calculating Relative Atomic Mass
Calculate the average atomic mass for silicon if 92.21% of its atoms have a mass of amu, 4.70% have a mass of amu, and 3.09% have a mass of amu.

14. Answer
(27.98 x ) + (28.98 x 0.047) + (29.97 x ) = amu

15. How is the mole concept related to chemical formulas?
Chemical Formulas reveal composition
Shows the ratio between elements
NH4….. 1 mole of NH4 = 4 moles of H and 1 mole of N
H2O……. 1 mole of H2O = 2 moles of H and 1 mole of O

16. How is the mole concept related to chemical formulas?
Can calculate molar mass of compounds
NH4 : N= 1(14.00 amu)
4 H= 4(1.01 amu)
Atomic mass = g/mol
H2O : H = 2(1.01)
1 O = 1(16.00)
Atomic mass = 18.02

17. More formulas…. What is the molar mass of zinc chloride?
g/mole
What is the molar mass of barium nitrate?
g/mole

18. Percentage Composition
Percentage composition describes the percentage by mass of each element in a compound
Find the molar mass of the compound.
Divide the mass of the element of interest by the molar mass of the compound
Multiply by 100 to get the percent

19. Percentage Composition
Example 1: What is the percent composition of oxygen in water?
H2O: Molar mass = 2(1.01) + 1(16.00)
Molar mass = g/mole
Percent composition of oxygen:
(16.00/18.02) x 100 = 88.79%

20. Percentage Composition
Example 2: What is the percentage composition of potassium in potassium chlorate?
(39.09/122.55) x 100 = 31.89%

21. Extra Credit Opportunity!!
Create your own “mole”
Requirements:
Must create a stuffed animal
Write a 1 page (no double space) on how your mole character relates to Avogadro's number. Aka the story about your mole character.
A small index card description of your mole with its name on it
Can earn up to 20 points extra credit!!!! The more creative it is, the more points you will earn!!