1. Do Now 9/3: create groups of 3-4. Each must have someone who took a year of chem.

2. Review: THE MOLE IB CHEM

3. Unit conversions  Multiply a number w/unit by a fraction  The fraction must be = to 1 (ie top = bottom)  Numerator has different units than denominator  Arrange fraction so desired units cancel. Examples: How many inches in 3.45 ft? 3.45 ft 12 inch = 41.4 inches 1 ft How many seconds in 4.25 days? 4.25 day 24 hr 60 min60sec = 367,000 sec 1 day1 hr1 min

4. The Mole One mole = 6.02 x 10 23 602,000,000,000,000,000,000,000 of anything…. But, most often used for really, really small things like atoms and molecules.

5. Where does the number come from?  The mole is defined by the number of carbon atoms found in exactly 12 grams of carbon 12.

6.  How many atoms are in 4.2 moles of carbon? 4.2 moles C x 6.02 x 10 23 atoms C = 2.5 x 10 24 atoms C 1 mole C  How many atoms are in 4.2 moles of magnesium? 4.2 moles Mg x 6.02 x 10 23 atoms Mg = 2.5 x 10 24 atoms Mg 1 mole Mg

7. The Mole Example: How Many Molecules of water are in a mole of water molecules? 6.02 x 10 23 molecules

8. The Mole We can also go from number of particles to moles: How many moles of Ca in 5.72 x 10 24 atoms of calcium? 5.72 x 10 24 atoms Ca 1 mole Ca = 9.50 moles Ca 6.02 x 10 23 atoms Ca

9. The Mole How many moles of Mg in 9.76 x 10 23 atoms of magnesium?

10. The Mole How many much mass does 3.00 moles of carbon atoms have?

11. The Mole How many much mass does 7.85 moles of potassium atoms have?

12. The Mole How many much mass does 2.37 moles of carbon atoms have?

13. The Mole How many much mass does 2.58 moles of water molecules (H 2 O) have?

14. The Mole How many much mass does 7.25 x 10 23 molecules of carbon dioxide (CO 2 ) have?