1. Chapter 11 Notes, Part I What is a mole? One Step Problems

2. What is a mole? A furry, burrowing woodland creature, revered by many and adored by all? Maybe! But not really in chemistry!

3. A Mole... is a unit of measurement that tells how many particles of something you have!

4. much like a dozen (12), a gross (144) or a ream (500) is just a unit that groups smaller numbers into big ones...but its a big one; a REALLY big one!

5. 1 mole = 6.02 x 10 23 particles! (that’s a lot of flowers!)

6. What are particles? Particles could be anything, but because of the size of the number, we usually mean Atoms, molecules, or formula units.

7. Avogadro’s Number The number 6.02 x 10 23 is called Avogadro’s number. This is due to Amadeo Avagadro’s research leading to the discovery, not the discovery of the number itself. It is a little known fact that Avogadro was voted his class’s most likely to have a scientific discovery and most likely to look really creepy.

8. Obj. 1…Formula vs. Molecular Mass Formula mass = total mass of ionic compounds - starts with a metal - starts with a metal Molecular mass = total mass of molecular compounds - starts with a non-metal - starts with a non-metal To calculate… - find mass of each element on P.T. (whole #s) - find mass of each element on P.T. (whole #s) - multiply mass by subscript and/or coefficient - multiply mass by subscript and/or coefficient - add all masses together for total mass - add all masses together for total mass

9. Obj. 1 cont… Practice… Al 2 (SO 4 ) 3 27 x 2 = 54 32 x 3 = 96 16 x 12 = 192 54 + 96 + 192 = 342 amu formula mass S3F6 S3F6S3F6 S3F6 32 x 3 = 96 19 x 6 = 114 96 + 114 = 210 amu molecular mass

10. more practice… more practice… Obj. 1 cont… 3CaC 2 O 4 40 x 3 = 120 12 x 6 = 72 16 x 12 = 192 120 + 72 + 192 = 384 amu OR 40 x 1 = 40 12 x 2 = 24 16 x 4 = 64 40 + 24 + 64 = 128 x 3 = 384 amu CuSO 4  5H 2 O two compounds chemically bonded together… NOT multiply!!! 64 32 64 10 80 64 + 32 + 64 + 10 + 80 = 250 amu

11. recall that one p + / n 0 = 1.67 x 10 -24 grams recall that one p + / n 0 = 1.67 x 10 -24 grams therefore…one mole of nucleons = 1 gram therefore…one mole of nucleons = 1 gram Obj. 2 cont… ** 1.67E -24 x 6.02E23 = 1 amu = g/mole amu = g/mole one mole = one mole = ~ 6.02 x 10 23 atoms, molecules or ions in a compound ~ molar mass of compound / element molar mass atomic mass ~ 22.4 liters of any gas at STP (standard temp. and pressure) 0°C 0°C 760 mmHg 101.3 kPa 1 atm 273K

12. Obj. 3-7…Mole Conversions MoleLiters # of atoms/ molecules Grams X by 22.4  by 22.4  by molar mass X by molar mass X by 6.02 x 10 23  by 6.02 x 10 23 use ‘mole map’ to solve mole conversions… use ‘mole map’ to solve mole conversions… ** going away from moles = x ** going toward moles = ÷

13. Obj. 3-7 cont… Practice, practice, practice… 2.0 moles He = ____________ atoms He 2.0 moles x 6.02E23 = 1.2 x 10 24 2.0 moles H 2 O = ____________ grams H 2 O 2.0 moles x 18 = 36 2 22 2 16 = 18 67.2 liters O 2 = ____________ moles O 2 67.2 liters ÷ 22.4 = 3.00 27 grams H 2 O = ____________ moles H 2 O 2 22 2 16 = 18 27 grams ÷ 18 = 1.5

14. Obj. 3-7 cont… more practice… 3.61 x 10 24 molecules NaCl = ____________ moles NaCl 3.61 x 10 24 molecules ÷ 6.02 x 10 23 = 6.00 5.0 moles CO 2 = ____________ liters CO 2 5.0 moles x 22.4 = 110 **3.61 x 10 24 molecules CO 2 = ____________ grams CO 2 ** ** 3.61 x 10 24 molecules CO 2 = ____________ grams CO 2 ** 3.61 x 10 24 molecules ÷ 6.02 x 10 23 = 6 moles x 2 12 32 = 44 44 grams = 264

15. Practice Problem #1 How many moles are in 2.57 x 10 25 atoms He?How many moles are in 2.57 x 10 25 atoms He?

16. Practice Problem #2 How many molecules of CO 2 are in 25.3 moles?

17. Practice Problem #3 How many moles of O 2 are in 29.3L of O 2 gas?

18. Practice Problem #4 If you have 3.6 moles of N 2 O (Nitrous oxide) how many liters would you have?

19. Practice Problem #5 How many grams of iron are in 3.5 moles?

20. Practice Problem #6 How many moles of Na 2 O are in 355.1g?