2. Catalyst – May 16/2 3, 2011 Grab a calculator please! 1. What is 0.25 of a dozen? 2. If a dozen hotdogs weighs 3 kilograms, how much does 3 dozen hotdogs weigh?

3. Today’s Agenda  Catalyst  Holy Moley!  Molar Mass  Convert It  Work Time  Exit Question

4. Today’s Objectives  SWBAT calculate the molar mass of an atom or molecule.  SWBAT perform stoichiometric conversions from moles to atoms and from moles to mass

5. What is a mole to us chemists?  A benign overgrowth of cells because of a failure in mitosis?  NO! But gross…  A rascly little rodent?  NOOOO!  A TV show featuring celebrities?  NOOOOO!  Then WHAT IS IT?????!!!???!?!?!???!!!!

6. The Mole Think of the term “a dozen”… How many donuts are in a dozen? How many eggs are in a dozen?

7. The Mole Just like a dozen refers to 12 objects…

8. The Mole Just like a dozen refers to 12 objects… … the MOLE refers to …

9. The Mole Just like a dozen refers to 12 objects… … the MOLE refers to … 6.02 x 10 23 particles

10. The Mole This number is called Avogadro’s number… 6.02 x 10 23 EQUALS 602,000,000,000,000,000,000,000

11. Avogadro’s Number 1 mole (mol) = 6.02 x 10 23 atoms 1 mol (mol) = 6.02 x 10 23 molecules (mlc) Why do YOU think we would do this?

12. What’s the point of all this?  Key Point #1: Avogadro's number (6.02 x 10 23 ) is used to convert between grams, moles, and atoms/molecules.  It all relates back to the mole…  Guess what’s coming back…

13. TRAIN TRACKS!!!  Step 1:  What to what?  Step 2:  Write conversion factor(s)  Step 3:  Train tracks

14. Stoichiometry Moles  Atoms/Molecules

15. Example #1: Avogadro’s Number Write this down!!! How many atoms are in 0.25 mol N 2 ?

16. TRAIN TRACKS!!!  Step 1:  What to what?  Step 2:  Write conversion factor(s)  Step 3:  Train tracks

17. Example #1: Avogadro’s Number Write this down!!! How many atoms are in 0.25 mol N 2 ? 1)What to What: mol N 2  atoms N 2 2)Conversion Factor: 1 mol = 6.02 x 10 23 atoms 3)Train Tracks!

18. Scientific Notation on the calculator  When you need to type in a scientific notation number like 6.02 x 10 23 …  Type 6.02 EE 23 instead SAVE TIME AND LOOK COOL!

19. How many atoms are in 1.1 moles of C 12 H 22 O 11 ? Your Turn! Avogadro’s Number

20. Stoichiometry Moles  Mass

21.  Key Point #2: Molar mass is the number of grams in one mole of a substance.  But Mr. Elder, how am I ever going to find out the molar mass of an element/compound?

22. Example #1: Molar Mass “What is the molar mass?” = How many grams are in one mole of a substance? 1 mol C = Write this down!!!

23. TRAIN TRACKS!!!  Step 1:  What to what?  Step 2:  Write conversion factor(s)  Step 3:  Train tracks

24. Example #1: Molar Mass 1 mol C = 12.01 g C 1)What to What: mol C  grams C 2)Conversion Factor: 1 mol C = atomic mass C = 12.01 g 3)Train Tracks!

25. Example #1: Molar Mass 1 mol C = 12.01 g C

26. Example #2: Molar Mass 1 mol Na = Write this down!!!

27. Example #2: Molar Mass 1 mol Na = 22.99 g Na

28. Step-Up Problem: Can you figure this one out? 1 mol CO 2 =

29. Step-Up Problem: Can you figure this one out? 1 mol CO 2 = 44.01 g

30. Try This One! Molar Mass 1 mol KNO 3 =

31. Try This One! Molar Mass 1 mol KNO 3 = 101.1 g

32. Stoichiometry Moles  Mass

33. Step-Up Problem: Moles to Mass If we have 3.5 moles of KNO 3, how many grams would we have? Write this down!!! 1)What to What: mol KNO 3  grams KNO 3 2)Conversion Factor: 1 mol KNO 3 = atomic mass KNO 3 = 101.1 g 3)Train Tracks!

34. Molar Mass If we have 20 grams CH 4, how many moles of CH 4 do we have? Write this down!!!

35. Independent Practice  Worksheet time!  Show Train Tracks on #7-14

36. Exit Question 1. How many atoms are in 1 mole of NH 4 ? 2. How many grams are there in 2.3 moles of NH 4 ?