1. 1/4 Opener
Convert the following: You have a sample of unobtainium that has a mass of 3.2kg. If the density of unobtanium is .793g/ml what is the volume of your sample?

2. The Mole: A Measurement of Matter

3. Measuring Matter
We often measure the amount of something by count, mass and volume
Examples?
Count: 1 dozen apples = 12 apples
Mass: 1 dozen apples = 2.0 kg apples
Volume: 1 dozen apples = 0.20 bushel apples

4. What is a Mole? A mole is how we measure in Chemistry
A mole represents 6.02 × 1023 particles of a substance
This number is also known as Avogadro’s number

5. Converting Number of Particles to Moles
# particles × ___1 mole_______ = Moles
6.02 × 1023 particles
If you have 1.5 x 1024 particles of MgCl2 how many moles do you have? How many Cl atoms do you have?
1.5 x 1024 particles MgCl2
1 mol MgCl2
=2.49 mol MgCl2
6.02 x 1023 Particles MgCl2

6. Individual Practice
If you have 4.6 x 1023 particles of KCl how many moles do you have?
If you have 5.2 x 1024 particles of CaO how many moles do you have?
If you have 9.8 x 1022 particles of Na2S how many moles do you have? How many moles of Na are there?
.76 mol KCl
8.63 mol CaO
.16 mol Na2S

7. Converting Moles to Number of Particles
moles × 6.02 × 1023 particles = # particles 1 mole How many particles are in 1.3 moles of Gold (Au)?
1.3 mol Au
6.02 x 1023 Particles Au
=7.286 x 1023 Particles Au
1 mol Au

8. Individual Practice How many particles are in 15.5 moles of NaCl?
How many particles are in .2 moles of Argon?
How many particles are in 1.3 moles of Gold (Au)?
How many particles of Hydrogen are in 4 moles of NH3?
9.331 x 10^23
1.204 x 10^23
7.826 x 10^23
2.408 x 10^24

9. The Mass of a Mole of an Element or Compound
Molar Mass: The atomic mass of an element (amu) expressed in grams equals the mass of a mole of that element.
ex. 1 mole H = grams
Calculating Molar Mass of Compounds
Find the molar mass of each element in one mole of the compound.
Check to see how many moles of each element are in the compound (multiply these subscripts by the molar mass of the element)
Add the masses of the elements in the compound

10. Practice
What is the molar mass of MgCl2 Mg= g/mol x 1 mol= g Cl= g/mol x 2 mol= 70.9 g Molar Mass MgCl = g/mol

11. Individual Practice What is the molar mass of BF3?
What is the molar mass of CaCl2?
What is the molar mass of Na2O?
What is the molar mass of LiBr?
67.81 g/mol
g/mol
61.98 g/mol
86.84 g/mol

12. Grams to Moles # grams x 1 mole molar mass (g)
This can also be accomplished by dividing the given amount of grams by your molar mass. Grams cancel and you are left with moles.
How many moles are there in 12 grams of FeCl2?
What is the molar mass of FeCl2?
Fe= 55.85g + 2 x Cl= g
Convert grams to moles
= grams FeCl2
12 grams FeCl2
1 mol FeCl2
= .095 mol FeCl2
grams FeCl2

13. Grams to Moles # moles x molar mass (g) 1 mole
This can also be accomplished by multiplying the given amount of moles by your molar mass. Moles cancel and you are left with grams.
How many grams are there in 3.4 moles of NH3?
What is the molar mass of NH3?
N= 14.01g + 3 x H= 3.03 g
Convert moles to grams
= grams of NH3
3.4 moles NH3
17.04 grams of NH3
= grams NH3
1 mol NH3

14. Mole Road Map