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Chapter 7 : Chemical Quantities

Chapter 7 : Chemical Quantities. College Prep Chemistry Mrs. Lips. MOLE. How many definitions did you come up with?. Definitions of a Mole. Any of various small insectivorous mammals , living chiefly underground.

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Chapter 7 : Chemical Quantities

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  1. Chapter 7: Chemical Quantities College Prep Chemistry Mrs. Lips

  2. MOLE How many definitions did you come up with?

  3. Definitions of a Mole • Any of various small insectivorous mammals, living chiefly underground. 2. A spy who becomes part of and works from within the ranks of an enemy governmental staff or intelligence agency.

  4. Definitions of a Mole 3.Machinery. A large, powerful machine for boring through earth or rock, used in the construction of tunnels. • A small, congenital spot or blemish on the human skin, usually of a dark color, slightly elevated, and sometimes hairy.

  5. Definitions of a Mole 5. A massive structure, esp. of stone, set up in the water, as for a breakwater or a pier. 6. An anchorage or harbor protected by such a structure. 7. A fleshy mass in the uterus formed by a hemorrhagic dead ovum.

  6. Definitions of a Mole 8. A spicy sauce flavored with chocolate, usually served with turkey or chicken. 9. The amount of a substance that contains as many atoms, molecules, ions, or other elementary units as the number of atoms in. The number is 6.02 × 1023, or Avogadro's number.

  7. Chapter 7 deals with measuring matter…we live in a quantitative world! • How do you order donuts? • How do you order cans of soda? • How do you order computer paper? • How do you order jelly beans? • How do you order lunchmeat? • You use a counting/measuring amount!

  8. The Mole: A Measurement of Matter • 1 dozen donuts = 12 donuts • 1 case of soda = 24 cans • 1 ream of paper = 500 sheets • 1 pound of jelly beans = ~350 j.b. • 1 pound of turkey = ~25 slices

  9. CH7: measurement in chemistry • Atoms are VERY SMALL! • One atom cannot be seen with the naked eye • An EXTREMELY large amount would have to be used to see it with the naked eye

  10. The Mole (mol) • Si unit for measuring large quantities of representative particles (atoms, molecules, formula units) • Avogadro’s number = 6.02 x 1023 • 1 mol N = 6.02 x 1023 atoms • 1 mol N2 = 6.02 x 1023 molecules • 1 mol H2O = 6.02 x 1023 molecules • 1 molNaCl = 6.02 x 1023formula units Avogadro’s # The # of atoms in 12 g of carbon

  11. How big is Avogadro’s # really??? • 602,000,000,000,000,000,000,000 • 1 mole of paperclips • goes around earth 4 trillion times • 1 mole of large marshmallows: • cover the continental USA 650 miles deep • 1 mole of marbles: • 116 times the size of Mt. Everest

  12. How big is Avogadro’s # really??? • Pretty big…yes? • Can you take a guess at the quantity of a mole of water molecules?

  13. 1 Mole of Water • Is equal to 18 mL …that’s how small molecules really are!

  14. Mole of other substances: • Mole of iron = 55.85 g • Mole of sulfur = 32.07 g • It’s not individual grains of iron or sulfur! • Where are these numbers coming from? Periodic table!!!

  15. Molar Mass • The mass of one mole of a substance (Units: g/mol) • Atomic mass on the periodic table • Rounded to two decimal places • Hydrogen gets 3 decimal places

  16. Molar Mass

  17. Molar Mass examples • Carbon = 12.0107 • Molar mass rounds to 12.01 g/mol • Oxygen = 15.9994 • Molar mass rounds to 16.00 g/mol • Hydrogen = 1.00794 • Molar mass rounds to 1.008 g/mol

  18. Types of Molar Masses • Gram Atomic Mass (gam) = molar mass of an element (Fe, S, C) • Gram Molecular Mass (gmm) = molar mass of a molecular compound (N2, H2O) • Gram Formula Mass (gfm) = molar mass of ionic compound (NaCl, FeSO4)

  19. Gram Atomic Mass (GAM) • Look at periodic table • GAM = atomic mass • EXAMPLES • W • Si • (183.85 g/mol) • (28.09 g/mol)

  20. Molar Mass • What if you have a compound? • 1 mole NaCl = 58.44 g/mol • How did you get that mass?

  21. Molar Mass • NaCl

  22. Gram Molecular Mass (GMM) • Nonmetal-nonmetal compounds • EXAMPLES • H2O • CO2 • C12H22O11

  23. Gram Molecular Mass (GMM) • H2O

  24. Gram Molecular Mass (GMM) • CO2

  25. Gram Molecular Mass (GMM) • What is the molar mass of sugar? C12H22O11?

  26. Gram Formula Mass (GFM) • Metal-nonmetal compounds • EXAMPLES • NaCl • FeBr3 • Zn3(PO4)2

  27. Gram Formula Mass (GFM) • NaCl

  28. Gram Formula Mass (GFM) • FeBr3

  29. Gram Formula Mass (GFM) • What is the molar mass of Zn3(PO4)2?

  30. Gram Formula Mass (GFM) • Zn3(PO4)2 3-Zn x 65.38 g/mol = 196.14 g/mol 2-P x 30.97 g/mol = 61.94 g/mol + 8-O x 16.00 g/mol = 128.00 g/mol 386.08 g/mol

  31. Mole Conversions • If one mole of water is 18.02 g, how much would two moles weigh? • 36.04 g • How much would 3 moles weigh? • 54.06 g • If one mole of water is 18.02 g, how many moles are in 90.1 g? • 5 moles

  32. Mole Conversions Three types of Mole Conversions • Mole – mass (g) • Mole – representative particles (molecules, atoms, f.u.) • Mole – volume (L)

  33. Mole-Mass Problem #1 How much does 4 moles of NaCl weigh? Given: Unknown: Conversion Factor: Solve: 4 moles NaCl g NaCl Molar mass of NaCl 1 mole NaCl = 58.44 g NaCl 4 mol NaCl x 58.44 g NaCl = 233.76 g NaCl 1 mol NaCl

  34. Mole-Mass Problem #1 How much does 4 moles of NaCl weigh? Given: Unknown: Conversion Factor: Solve:

  35. Mole Conversions Three types of Mole Conversions • Mole – mass (g) • Mole – representative particles (molecules, atoms, f.u.) • Mole – volume (L)

  36. The Mole (mol) • Avogadro’s number = 6.02 x 1023 • 1 mol N = 6.02 x 1023 atoms • 1 mol N2 = 6.02 x 1023 molecules • 1 mol H2O = 6.02 x 1023 molecules • 1 molNaCl = 6.02 x 1023formula units Avogadro’s # The # of atoms in 12 g of carbon

  37. Mole-Representative Practice Problem #1 How many moles is 2.107x1024molecules (mo) of O2? Given: Unknown: Conversion Factor: Solve:

  38. Mole-Representative Practice Problem #2 How many atoms are in 12.5 moles of Copper? Given: Unknown: Conversion Factor: Solve:

  39. Mole Conversions Three types of Mole Conversions • Mole – mass (g) • Mole – representative particles (molecules, atoms, f.u.) • Mole – volume (L)

  40. Molar Volume • Definition: the amount of space that 1 mole of ANY gas occupies at STP conditions (a constant) • MOLAR VOLUME = 22.4 L

  41. Molar Volume • Standard Temperature and Pressure (STP): specific conditions that can be reached in the lab • Standard Pressure: 1 atmosphere (atm) • Standard Temperature: 0oC or 273 K

  42. Mole-Volume Problem #1 • How many moles is 145.6 L of O2 gas at STP? Given: Unknown: Conversion Factor: ? Solve:

  43. Mole-Volume Problem #2 • How many liters is 11 moles of O2 gas at STP? Given: Unknown: Conversion Factor: ? Solve:

  44. Mole Road Map Problems • How many liters of gas are 3.612x1024 atoms of Neongas at STP? • Given: • Unknown: • Conversion Factor: ? • Solve:

  45. Mole Road Map Problem Given: 3.612x1024 at Neon Unknown: L Ne ? Conversion Factor: needs TWO! • Avogadro’s number 1 mole Ne = 6.02x1023 at Ne • molar volume 1 mole Ne = 22.4 L Ne THERE IS NO DIRECT ROAD FROM AT  L

  46. What percent of your bag by mass is your notes if you carry… • 3 lbs textbooks • 1 lb notes • ½ lb pens and pencils • ½ schoolbag

  47. Percent Composition • Definition: percent by mass of each element in a compound • For example, what percent of water is hydrogen?

  48. % Composition Problem • Example: What is the percent composition of each element in water? • First calculate the molar mass of water

  49. % Composition Problem • Molar Mass of Water: • Next, divide the mass that each element contributes to the molar mass by the molar mass of the compound and multiply by 100. % H: % O:

  50. % Composition Problem 2 • What is the percent composition of each element in aluminum sulfate? • First calculate the molar mass of Al2(SO4)3 2-Al x 26.98 g/mol = 53.96 g Al 3-S x 32.07 g/mol = 96.21 g S 12-O x 16.00 g/mol = 192.00 g O 342.17 g Al2(SO4)3

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