1. What the mole?!? You don’t scare me, Chapter 11!

2. For each question asked: ► Copy question (These are on the blog if you aren’t fast enough in class.) ► Determine which type of problem is being asked ► Set up problem (Solving is for homework.)

3. #1 ► How many molecules are collected in 6.50 moles of CuCl 2 ?

4. #2 ► 48.675g of bismuth represents how many atoms of bismuth?

5. #3 ► What is the molar mass of chlorine gas?  Be careful of the formula!!

6. #4 ► Dr. Bubba (chemist extraordinaire) wants to use.450 mol of aluminum sulfide. How much should be measured onto the balance?

7. #5 ► A compound has a molar mass of 110.1g/mol. Its percent composition seems to indicate an empirical formula of C 3 H 3 O. ► Is that the correct formula for the compound?

8. #6 ► What percent of gypsum is actually calcium?  (gypsum = CaSO 4 · 2H 2 O)

9. #7 ► What percent of gypsum is actually water?

10. #8 ► How many moles of iron (III) nitrate are represented by 43.56mg of the salt?  (Hey! Is that a milligram?)

11. #9 ► What is the average mass of 50 atoms of sulfur?

12. #10 ► Styrene is 92.25% carbon and 7.75% hydrogen. What empirical formula does that indicate?

13. #11 ► The molar mass of styrene is 104g/mol. What must be the molecular formula?  (Yep, use #10 to figure this out.)

14. #12 ► How many molecules of CO 2 are in 44.10g of carbon dioxide?

15. #13 ► What percent of anhydrous copper (II) sulfate is oxygen?

16. #14 ► What is the empirical formula of a compound containing:  10.52g nickel  4.38g carbon  5.10g nitrogen

17. #15 ► One billion molecules of water are in your hand; how many moles of molecules are you holding?

18. Fine’ ► So, how did you do? ► E-mail your results to me for bonus points! (Shhhh, it’s our secret!!)  Valid only til 2/10/11……

19. #1 ► How many molecules are collected in 6.50 moles of CuCl 2 ? ► 6.50mol CuCl 2 (6.022 x 10 23 molecules) ► ( 1 mole CuCl 2 ) ► 3.91 x 10 24 molecules CuCl 2

20. #2 ► 48.675g of bismuth represents how many atoms of bismuth? ► 48.675g (6.022 x 10 23 atoms Bi) ► (208.98038g Bi) ► 1.403 x 10 23 atoms of Bi

21. #3 ► What is the molar mass of chlorine gas?  Be careful of the formula!! Chlorine is Cl 2 !! ► 2(35.453g/mol) = 70.906g/mol Cl 2

22. #4 ► Dr. Bubba (chemist extraordinaire) wants to use.450 mol of aluminum sulfide. How much should be measured onto the balance? ► 0.450mol Al 2 S 3 (150.162g Al 2 S 3 ) ► (1 mol Al 2 S 3 ) ► 67.6 g Al 2 S 3

23. #5 ► A compound has a molar mass of 110.1g/mol. Its percent composition seems to indicate an empirical formula of C 3 H 3 O. ► Is that the correct formula for the compound?  C 3 H 3 O = 55.056g/mol which is only half of the required 110.1g/mol ► No, C 6 H 6 O 2 is the correct molecular formula.

24. #6 ► What percent of gypsum is actually calcium?  (gypsum = CaSO 4 · 2H 2 O) ► Ca x 100 ► CaSO 4 ·2H 2 O ► 40.08/172.18x100 = 23.28% Ca

25. #7 ► What percent of gypsum is actually water? ► 2H 2 O x 100 ► CaSO 4 ·2H 2 O ► 36.030/172.18x100 = 20.926% H 2 O

26. #8 ► How many moles of iron (III) nitrate are represented by 43.56mg of the salt?  (Hey! Is that a milligram?) ► 43.56mg Fe(NO 3 ) 3 (10 -3 g) (1 mole) = ► (1 mg) (241.859g) ► 1.801 x 10 -4 moles Fe(NO 3 ) 3

27. #9 ► What is the average mass of 50 atoms of sulfur? ► 50 atoms S (32.066 g S) = ► (6.022 x 10 23 atoms S) ► 2.662 x 10 -21 g S (Note: 4 sig figs) ► (Note: the smallest mass unit we saw was the attogram which is 10 -18 )

28. #10 ► Styrene is 92.25% carbon and 7.75% hydrogen. What empirical formula does that indicate? ► CH

29. #11 ► The molar mass of styrene is 104g/mol. What must be the molecular formula?  (Yep, use #10 to figure this out.) ► CH = 13.019g/mol AND 104/13 = 8 ► Therefore, styrene is C 8 H 8

30. #12 ► How many molecules of CO 2 are in 44.10g of carbon dioxide? ► 6.022 x 10 23 molecules CO 2 ► The mass given happens to be the molar mass which IS the mass of Avogadro’s number for CO 2 This one of those that if you recognize that number as its molar mass, you don’t even have to calculate.

31. #13 ► What percent of anhydrous copper (II) sulfate is oxygen? ► 4O/CuSO 4 x 100 ► 40.096% oxygen

32. #14 ► What is the empirical formula of a compound containing:  10.52g nickel  4.38g carbon  5.10g nitrogen ► Ni(CN) 2 nickel (II) cyanide ► Most of you would have CORRECTLY put NiC 2 N 2 Try to recognize polyatomic ions with metals.

33. #15 ► One billion molecules of water are in your hand; how many moles of molecules are you holding? ► 1 x 10 9 molecules H 2 O (1 mole H 2 O) = ► (6.022 x 10 23 ) ► 1.661 x 10 -15 moles H 2 O, bet you thought it would be a big number, didn’t you?