1. Bellwork Solve the following using dimensional analysis and place the answer in scientific notation. 1. Jamie has 2.5 liters of mercury in a jar. What is the mass of this mercury if its density is 13.6 g/ml?

3. The mole (mol) is one of the seven base units in the SI system. It measures the amount of substance.

4. The form in which a substance exists is its “representative particle”. Representative particles can be atoms, ions, molecules, formula units, or anything else.

5. Just as one dozen is 12 representative particles of eggs, a mole is 6.02 x 10 23 representative particles. 602,000,000, 000,000,000, 000,000!!!!!

6. Examples: 1 mole Fe = 6.02 x 10 23 atoms of Fe 1 mole H 2 O molecules = 6.02 x 10 23 molecules of water 1 mole NaCl formula units = 6.02 x 10 23 NaCl formula units 1 mole eggs = 6.02 x 10 23 eggs You can have a mole of ANYTHING!!

7. 6.02 X 10 23 Watermelon Seeds: Would be found inside a melon slightly larger than the moon. 6.02 X 10 23 Donut Holes: Would cover the earth and be 5 miles (8 km) deep. 6.02 X 10 23 Pennies: Would make at least 7 stacks that would reach the moon. 6.02 X 10 23 Grains of Sand: Would be more than all of the sand on Miami Beach. 6.02 X 10 23 Blood Cells: Would be more than the total number of blood cells found in every human on earth. How much is a mole?

8. Question How many molecules would be in 3 moles of water?

9. Diatomic Elements Certain elements are only stable in pairs or with other elements in a compound. These elements are called the diatomic elements.

10. There are 7 diatomic elements: Bromine, Iodine, Nitrogen, Chlorine, Hydrogen, Oxygen, and Fluorine (Memory trick: HBrONClIF or 7 th Heaven)

11. Avogadro’s Number *6.02 x 10 23 is called Avogadro’s number. *It is named after Amadeo Avogadro who did work in the 1800’s that allowed 6.02 x 10 23 to be calculated.

12. The mole is the “chemist’s dozen”. It is a convenient way to count extremely large numbers of atoms, molecules or ions.

13. New Conversion Factor! 1 mole = 6.02 x 10 23 representative particles We work these problems using dimensional analysis.

14. How many moles are 1.20 x 10 25 atoms of phosphorous? 1.20 x 10 25 atoms P 1 mol P 6.02 x 10 23 atoms = 19.9 mol P

15. How many atoms are in 0.750 mol of Zn? 0.750 mol Zn 6.02 x 10 23 atoms Zn = 1 mol Zn 4.52 x 10 23 atoms Zn

16. How many molecules are in 0.400 mol N 2 O 5 ? 0.400 mol N 2 O 5 6.02 x 10 23 molecules = 1 mole N 2 O 5 2.41 x 10 23 molecules Q: What did Avogadro teach his students in math class? A: Moletiplication

17. How many moles are contained in 1.20 x 10 24 molecules CO 2 ? 1.20 x 10 24 molec CO 2 1 mol CO 2 6.02 x 10 23 molecules = 1.99 moles CO 2

18. Question Your friend gives you a gold ring that contains 2.3 mol of atoms. How many atoms is this?

19. Gram atomic mass (gam) -atomic mass of an element in grams -mass of one mole of atoms of a monatomic element -use the periodic table and take masses to 0.1 g

20. Question Write the atomic masses of the following. Mg __________ Cl ___________ Ba ___________

21. Example: C =12.0 g = mass of 6.02 x 10 23 atoms 12.0 g/mol is the gram atomic mass of carbon

22. There are two terms to describe the mass of a chemical compound; gram molecular mass and gram formula mass. We will most often use the term gram formula mass. Molar mass of molecular weight are terms also used to mean the same thing.

23. Gram molecular mass (gmm) -mass of one mole of any molecule -sum of the atomic masses of each atom in the molecule 1 mol H 2 O: 2 mol H 1 mol O =2 mol H x 1.0 g H/mol = 2.0 g =1 mol O x 16.0 g O/mol= 16.0 g 18.0 g H 2 O

24. Question What is the gram molecular mass of P 2 O 5 ?

25. What is the gram molecular mass of CH 3 OH? C 1 x 12.0 = 12.0 H 4 x 1.0 = 4.0 O 1 x 16.0 = 16.0 32.0 g

26. Gram formula mass (gfm) -mass of one mole of an ionic compound -sum of the atomic masses of each atom in a formula unit

27. What is the gfm of magnesium phosphate? Mg 3 (PO 4 ) 2 3 mol Mg 3 x 24.3 g = 72.9 g 2 mol P 2 x 31.0 g = 62.0 g 8 mol O 8 x 16.0 g =128.0 g 262.9 g

28. What is the molar mass of ammonium sulfate? (NH 4 ) 2 SO 4 2 mol N 2 x 14.0 = 28.0 8 mol H 8 x 1.0 = 8.0 1 mol S 1 x 32.1 = 32.1 4 mol O 4 x 16.0 = 64.0 132.1 g

29. Bellwork Monday, October 15 th What is the gram molar mass of methane? Methane’s formula is CH 4

30. Mole – Mass Conversions New Conversion factor! 1 mol = gfm

31. Find the mass in grams of 3.32 mol of K. 3.32 mol K 39.1 g K 1 mol K = 1.30 x 10 2 g K

32. Find the mass in grams of 15.0 mol of sulfuric acid. H 2 SO 4 H 2 x 1.0 = 2.0 S 1 x 32.1 = 32.1 O 4 x 16.0 = 64.0 98.1 g 15.0 mol H 2 SO 4 98.1 g H 2 SO 4 1 mol H 2 SO 4 = 1470 g H 2 SO 4

33. Find the number of moles in 11.0 g of methane (CH 4 ). CH 4 = (12.0g + 4.0g = 16.0 g) 11.0 g CH 4 1 mol CH 4 16.0 g CH 4 = 0.688 mol CH 4 What was Avogadro’s favorite Indian tribe? The MOLEHICANS

34. Molti-Step Mole Problems! Calculate the number of molecules present in 4.29 g of nitrogen dioxide (NO 2 ). 4.29 g NO 2 1 mol NO 2 6.02x10 23 m.c. NO 2 = 46.0 g NO 2 1 mol NO 2 = 5.61x10 22 molecules NO 2

35. Calculate the number of moles of sulfur atoms present in 2.01 g of sodium sulfide (Na 2 S). 2.01 g Na 2 S 1 mol Na 2 S 1 mol S atoms 78.1 g Na 2 S 1 mol Na 2 S = 0.0257 mol S atoms Molti-Step Mole Problems!

36. Calculate the mass in grams of 2.49 x 10 20 carbon dioxide (CO 2 ) molecules. 2.49 x 10 20 CO 2 m.c. 1 mol CO 2 44.0 g CO 2 6.02x10 23 m.c. CO 2 1 mol CO 2 = 1.82 x 10 -2 grams CO 2 Molti-Step Mole Problems!

37. Calculate the grams of carbon in 12.2 mol sucrose, C 12 H 22 O 11. 12.2 mol C 12 H 22 O 11 12 mol C atoms 12.0 g C 1 mol C 12 H 22 O 11 1 mol C atoms = 1.76 x 10 3 g carbon Molti-Step Mole Problems!

38. Question Write the two conversion factors we have discussed below. Show how they are related.

39. Molar Volume of a Gas The volume of a gas is usually measured at 0 o C and 1 atmosphere of pressure. This is called standard temperature and pressure (STP). Know these values!

40. -At STP, one mole of any gas has a volume of 22.4 L which is called the molar volume of a gas and contains 6.02 x 10 23 particles of the gas. -22.4 L of a gas has a mass equal to the gfm of the gas. -So… 1 mol = 22.4L = 6.02 x 10 23 particles = gfm Again, you have to know!

41. New conversion factor! 1 mol of any gas at STP = 22.4 L (for gases only)

42. What is the volume (liters) at STP of 0.960 mol of methane, CH 4 ? 0.960 mol CH 4 22.4 L CH 4 1 mol CH 4 =21.5 L CH 4

43. At STP, how many moles are in 0.542 mL of neon gas? 0.542 mL Ne 1 L Ne 1 mol Ne 1000 mL Ne 22.4 L Ne = 2.42 x 10 -5 mol Ne

44. Question Relate the three conversion factors we have learned below.

45. Bellwork Tuesday, October 16 th Jake has a jar full of sodium hydrogen carbonate, or baking soda (NaHCO 3 ). What is the mass of 2.78 mol baking soda?

46. Homework Check! Tuesday Homework- show all of your work! One mole = _____________ particles A neon sign has 2.64 x 10 24 atoms of neon. How many moles is this? How many molecules of sugar are there in an ice cream cone with 2.34 moles of sugar? What is the gram molecular mass of water? What is the gram formula mass of calcium carbonate?

47. Percent Composition (remember: percent = part divided by total x 100) percent by mass of each element in a compound

48. Find the % composition for a compound that is formed from 28.0 g of Fe and 8.0 g O. 28.0 g Fe + 8.0 g O = 36.0 g total 28.0 g Fe x 100 = 77.8 % Fe 36.0g total 8.0 g O x 100 = 22.2 % O 36.0g total

49. Why is Avogadro so rich! Because he is a multi- mole-ionairre!!!!

50. What is the percent composition of calcium acetate? Ca(C 2 H 3 O 2 ) 2 Ca 1 x 40.1 = 40.1 C 4 x 12.0 = 48.0 H 6 x 1.0 = 6.0 O 4 x 16.0= 64.0 158.1 g ( /158.1g) x 100 =25.4% Ca ( /158.1g) x 100 =30.4% C ( / 158.1g) x 100 = 3.8% H ( /158.1g) x 100 = 40.5% O 100.1%

52. Bellwork Wednesday, October 17 th Susannah has 12.5g of HC 2 H 3 O 2, or vinegar. How many MOLECULES of vinegar does she have?

53. An empty balloon has a mass of 5.66g. When filled with hydrogen gas (H 2 ), the balloon has a mass of 6.12g. *How many grams of H 2 were used to inflate the balloon? ___________ *What is the average atomic mass of H 2 ? _________________ *Some balloons are filled with helium. What is the average atomic mass of helium? ______________ *If a balloon is filled with O 2 and with Ar, which balloon would sink faster and why? __________________

55. What is the mass of one mole of hydrogen peroxide, H 2 O 2 ? What is the mass of ten moles of hydrogen peroxide?

56. CALCULATING EMPIRICAL FORMULAS Empirical formula - lowest whole number ratio of the elements in a compound - may or may not be the same as the molecular formula.

57. Steps to calculate empirical formula: 1. Find moles of each element. 2. Set up mole ratio. 3. Simplify mole ratio (divide by smallest). If your answers are not in whole numbers, you must multiply by 2,3,4,or 5 to get whole numbers. 4. Use mole ratio as subscripts in the formula. If given % composition, assume 100 g of compound. Empirical Formula Poem Percent to mass, mass to moles, divide by smallest and round ‘till whole!

58. A compound is 79.8% C and 20.2% H. Find its empirical formula. 79.8gC 1mol C = 6.65 mol C 12.0 g C 20.2 g H 1 mol H = 20.0 mol H 1.01 g H CH 3 /6.65 = 1 /6.65 = 3

60. Find the empirical formula for a compound made up of 26.7% P, 12.1% N and 61.2% Cl. 26.7 g P 1 mol P = 0.861 mol P 31.0 g P 12.1 g N 1 mol N = 0.864 mol N 14.0 g N 61.2 g Cl 1 mol Cl = 1.72 mol Cl 35.5 g Cl /0.861=1 /0.861=2 Empirical Formula = PNCl 2

61. Bellwork Thursday, October 18 th NutraSweet is 57.14% C, 6.16% H, 9.52% N, and 27.18% O. Calculate the empirical formula of NutraSweet.

62. Homework check To fill the Goodyear Blimp 7,017 m³ of helium are used. How many moles of helium is this if the balloon is filled at STP? (Hints: use dimensional analysis! 1 m 3 = 1000 L) How many kilograms of helium are used (1 kg = 1000g)? If one tank of helium holds 291 ft 3 how many tanks do you need to fill up the Goodyear Blimp? (Hint 1 ft 3 = 28.315 L)

63. Molecular formulas are the actual formulas. They may be the same as the empirical formula or a multiple of it.

64. To find the multiple (n), take the gram formulas mass (gfm) and divide by the empirical formula mass (efm): n = gfm efm Multiply each subscript in the empirical formula by n to get the molecular formula.

65. A white powder is analyzed and found to have the empirical formula P 2 O 5. The compound has a molar mass of 283.9 g. What is the compound’s molecular formula? P 2 O 5 = 142.0 g/mol gfm/efm 283.9 g/mol 142.0 g/mol = 2 2(P 2 O 5 ) = P 4 O 10

66. A compound used as an additive for gasoline to help prevent engine knock shows the following percentage composition: 71.65% Cl24.27% C4.07% H The molar mass is known to be 98.96 g. Determine the empirical formula and the molecular formula for this compound. 71.65 g Cl 1 mol Cl = 2.02 mol Cl 35.5 g Cl 24.27g C 1 mol C = 2.02 mol C 12.0 g C 4.07g H 1 mol H = 4.03 mol H 1.01 g H 1:1:2 ClCH 2 or CH 2 Cl efm = 12.0+2.0+35.5=49.5 g/mol 98.96/49.5=2 C 2 H 4 Cl 2 /2.02 = 1 /2.02 = 2

69. Bellwork Friday, October 19 th How many moles of each substance are contained in the following samples? Be sure to include the correct units and sig figs in your answers. a) 6.0 x 10 20 molecules of carbon dioxide b) 7.409 x 10 13 molecules of water c) 5 x 10 46 molecules of methane (CH 4 )

70. Bellwork Tuesday, October 22 nd You have 10.0 g of aluminum and 73.0 g of gold. Which sample contains more total atoms, the aluminum or gold?

71. Bellwork Tuesday, October 23 rd Happy Mole Day! Write down your favorite thing about chemistry so far this year!

72. Homework Check A Determine the empirical formula of the compound containing 26.1% C, 4.3% H, and 69.6% O by weight? Which of the following could be an empirical formula? (you may circle more than one) –C 8 H 12 –CH 4 –NO 2 –N 2 O 14 –CCl 4

73. Bellwork Wednesday, October 24 th What is the molecular formula for a compound that is 46.16% carbon, 5.16% hydrogen and 48.68% fluorine if the molar mass of this compound is 156.12 g?

74. Homework Check! What is the empirical formula of aspirin? It has 4.48 % H, 60.00 % C, and 35.52 % O by mass. Aluminum sulfate, Al 2 (SO 4 ) 3, is a compound used in sewage treatment plants. How many grams of aluminum are in 7.344 mol of aluminum sulfate? How many oxygen atoms are in 40.0 liters of oxygen gas at STP?

75. Bellwork Thursday, October 25 th What is the empirical formula for a compound that contains 17.34% hydrogen and 82.66% carbon?

76. Homework Check! How many grams does 56.2 L of O 2 gas have? How many molecules does 5.32 g of hydrochloric acid (HCl) contain? A compound is made up of 6.93 g oxygen and 0.43g hydrogen. Find this compound’s empirical formula first, then find its molecular formula if the molar mass of the compound is 34.0 g/mol.

77. Friday Homework Check! What is the percent composition of each element in the compound calcium sulfate? A compound is made up of 94.1% oxygen and 5.9% hydrogen. Its molar mass is 34.00g. What are the empirical and molecular formulas of this compound? A substance was found to be composed of 22.9% Na, 21.5% B, and 55.7% O. What is the empirical formula of this compound?

78. A Mole Is a Unit A mole is an animal that burrows in the ground, Or a spot on your chin that you gotta shave around. But there's another kind of mole of interest to me, That's the kind of mole they use in chemistry. Chorus: A mole is a unit, or have you heard, Containing six times ten to the twenty-third, That's a six with twenty-three zero's at the end, Much too big a number to comprehend.

79. Say you had a mole of pennies to distribute 'round the world, Give to each of the five billion grownups, boys, and girls, There wouldn't be a single person down and out of luck, Cause everybody in the world would get a trillion bucks. Or say you had a mole of paper and stacked it toward the sky, Paper's awful thin, but that pile would get so high. It'd reach up into outer space, in fact I think you'd find, It'd go up to the moon and back, eighty billion times.

80. Chorus: A mole is a unit, or have you heard, Containing six times ten to the twenty-third, That's a six with twenty-three zero's at the end, Much too big a number to comprehend. Suppose a mole of marshmallows fell upon the planet, Over each square inch of land and sea, think that you could stand it? That layer would be twelve miles high and of course block our sun, We're talking close to five million trillion tons.

81. Well, maybe we could save ourselves if we all started eaten', One marshmallow each second, not two 'cause that'd be cheatin', With forty five billion people munching, how long do you think it'd take? Forty million years, and that's without a bathroom break. Chorus: A mole is a unit, or have you heard, Containing six times ten to the twenty-third, That's a six with twenty-three zero's at the end, Much too big a number to comprehend.

82. But say you had a mole of atoms, would the pile be immense, Should I say the answer now or leave you in suspense? Well, atoms are so very small, very small, you understand, You could hold a mole of atoms in the palm of your hand. So shake a little sugar in the middle of your palm, Now you don't want to spill it, so try and stay calm. You hardly can imagine and barely realize, There're more atoms in that sugar than stars up in the sky.

83. Homework Check! What is the empirical formula of aspirin? It has 4.48 % H, 60.00 % C, and 35.52 % O by mass.