1. FORMULA MATH & THE MOLE

2. The Mole Measuring Matter

3. In Chemistry, we commonly measure: Mass (grams) Mass (grams) Volume (L or mL) Volume (L or mL) Particles (counted) Particles (counted)

4. We can relate each of these measurements to a single quantity called the “Mole”. We can relate each of these measurements to a single quantity called the “Mole”.

5. The Mole is the SI unit for the The Mole is the SI unit for the “amount of something”

6. Why use it? To estimate the number of particles that are too small or too numerous to actually count. To estimate the number of particles that are too small or too numerous to actually count.

7. How big is a Mole? How big is a Mole? If you have a mole of pennies and divide them equally among the 6 billion people on Earth, how many dollars would each person get? If you have a mole of pennies and divide them equally among the 6 billion people on Earth, how many dollars would each person get?

8. 6.022 X10 23 pennies 6 x 10 9 people = $1x10 12 = $1x10 12 person person x 1 $ 100 100 pennies pennies Each person would get ~ $ 1 trillion!!!

9. Volume 1.0 mole = 22.4 Liters of a gas, at standard temperature and pressure (STP) 1.0 mole = 22.4 Liters of a gas, at standard temperature and pressure (STP) Std. temp. = 0º C or 273K Std. temp. = 0º C or 273K Std. pressure = 1 atmosphere (atm) Std. pressure = 1 atmosphere (atm) or 760 mm Hg (Torr)

10. Particles 1.0 mole = 6.022 x 10 23 particles of a pure substance. 1.0 mole = 6.022 x 10 23 particles of a pure substance. * Element = atom * Molecular = molecule (mlc) *Ionic = formula unit (fmu)

11. Mass 1.0 mole = ____ grams of a pure substance. 1.0 mole = ____ grams of a pure substance. (“Molar Mass” of that substance)

12. Molar Mass – mass, in grams, of 1 mole of a pure substance.

13. What is the Molar Mass of: Carbon tetrachloride

14. Comparing amounts 1 mole CCl 4 = 1 mole CCl 4 = _154.0_ grams _154.0_ grams 6.022 x 10 23 molecules 6.022 x 10 23 molecules Liters is N/A (not a gas) Liters is N/A (not a gas)

15. What is the Molar Mass of: Oxygen

16. Comparing amounts 1 mole O 2 = 1 mole O 2 = _32.0_ grams _32.0_ grams 6.022 x 10 23 molecules 6.022 x 10 23 molecules 22.4 Liters, at STP 22.4 Liters, at STP

17. What is the Molar Mass of: Aluminum carbonate

18. Comparing amounts 1 mole Al 2 (CO 3 ) 3 = 1 mole Al 2 (CO 3 ) 3 = _234.0_ grams _234.0_ grams 6.022 x 10 23 formula units 6.022 x 10 23 formula units Liters is N/A (not a gas) Liters is N/A (not a gas)

19. CalculatingwithMoles

20. Remember…. 1.0 mole = 6.022 x 10 23 particles = 22.4 liters of gas, at STP = ______ grams (Molar Mass)

21. Steps to calculate: READ directions in Lecture Packet.

22. Example What is the mass of 45.8 L of carbon dioxide gas, at STP?

23. Example How many moles are equal to 3.01 x 10 22 atoms of magnesium?

24. Example: How many molecules are in 38.69 grams of chlorine gas?

25. Example: What is the volume, in L, at STP, occupied by 0.600 moles of sulfur dioxide gas?

26. STOP

27. Percent Composition

28. Think about it... What is the percent composition of the number of boys to girls in this classroom?

29. Now, think about this... What is the percent composition of the weight of boys to girls in this classroom?

30. In Chemistry, it’s calculated the same way, except we consider the make-up of compounds.

31. What information does % Composition give us? The percent, by mass, of each element in a compound.

32. Formula: grams element ------------------------ X 100 = % grams compound grams compound

33. 2 Ways To Calculate: 1) Chemical Formula is given 2) Masses are given (no formula given)

34. If formula is given: 1) Write chemical formula. 2) Count atoms of each element in compound. 3) Multiply by Mass Number from P.T.(round all mass # to the 100 th ). 4) Add answers. 5) Plug numbers into formula and solve.

35. If actual masses are given: 1) Use Law of Conservation of Mass to determine elements and compound mass. 2) Use formula to calculate %.

36. Example #1 What is the percent composition of water?

38. Example#2 What is the % composition of calcium nitrate?

40. If masses are given: 1) g element + g element + g element g compound g compound * Remember the Law Of Conservation Of Mass Law Of Conservation Of Mass

41. Example#3 What is the percent composition of a compound if 27.07 grams of calcium completely reacts with 47.93 grams of chlorine?

43. Example#4 Chlorine reacts with 33.86 grams of phosphorus to form 150.00 grams of a compound. What is the % composition of the compound?

45. STOP

46. MoreFormulaMath!!!

47. Empirical Formula The simplest whole number The simplest whole number ratio of elements in a compound. Subscripts cannot be reduced. Subscripts cannot be reduced.

48. Molecular Formula The actual number of atoms of each element present in a substance. The actual number of atoms of each element present in a substance. Is a whole number multiple of the Empirical Formula. Is a whole number multiple of the Empirical Formula. Subscripts can be reduced. Subscripts can be reduced.

49. From the “mole” perspective… Ba 3 N 2 3 moles of barium reacts with 2 moles of nitrogen to form compound. 3 moles of barium reacts with 2 moles of nitrogen to form compound. Is an Empirical Formula because subscripts cannot be reduced. Is an Empirical Formula because subscripts cannot be reduced.

50. From the “mole” perspective… Al 2 (SO 4 ) 3 2 moles of aluminum reacts with 3 moles of sulfate to form compound. 2 moles of aluminum reacts with 3 moles of sulfate to form compound. Is an Empirical Formula because subscripts cannot be reduced. Is an Empirical Formula because subscripts cannot be reduced.

51. From the “mole” perspective… C 6 H 12 O 6 6 moles of carbon reacts with 12 moles of hydrogen and 6 moles of oxygen to form compound. 6 moles of carbon reacts with 12 moles of hydrogen and 6 moles of oxygen to form compound. Is a Molecular Formula because subscripts can be reduced. Is a Molecular Formula because subscripts can be reduced.

52. From the “mole” perspective… H 2 O 2 2 moles of hydrogen reacts with 2 moles of oxygen to form compound. 2 moles of hydrogen reacts with 2 moles of oxygen to form compound. Is a Molecular Formula because subscripts can be reduced. Is a Molecular Formula because subscripts can be reduced.

53. To calculate Empirical Formulas: READ direction on CHEAT SHEET!!!

54. example… What is the E.F. of a compound composed of 32.00% Carbon, 42.66% Oxygen, 18.67% Nitrogen, and 6.67% Hydrogen?

55. 1)Change % to grams (just change the sign)

56. 2) Convert from grams to moles (use a 1 step box)

57. 3) Make a “ratio” (divide all answers by the smallest one)

58. 4) Write formula

59. example… What is the E. F. of a compound composed of 25.9% Nitrogen and 74.1% Oxygen?

61. example… What is the E. F. of a compound composed of 36.6 grams of Carbon and 9.2 grams of Hydrogen?

63. To calculate Molecular Formulas: READ direction on CHEAT SHEET!!!

64. example…. What is the M.F. of a compound with a mass of 92.0 grams and an E.F. of NO 2 ?

65. example…. What is the M.F. of a compound with a mass of 150.0 grams and an E.F. of CH 2 O?

66. What is the M.F. of a compound with a mass of 150.0 grams and an E.F. of CH 2 O?

67. example…. What is the M.F. of a compound with a mass of 132 grams that is composed of 54.6% Carbon, 13.6% Hydrogen, and 31.8% Nitrogen?