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Monday, March 17 th : “A” Day Tuesday, March 18 th : “B” Day Agenda

Monday, March 17 th : “A” Day Tuesday, March 18 th : “B” Day Agenda. Ch. 6 Tests Begin Chapter 7: “The Mole and Chemical Composition” In-Class Assignments: Practice pg. 228: #1-4 Practice pg. 229: #1-4 Concept Review: “ Avo’s Number/Molar Conversions ”

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Monday, March 17 th : “A” Day Tuesday, March 18 th : “B” Day Agenda

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  1. Monday, March 17th: “A” Day Tuesday, March 18th: “B” DayAgenda • Ch. 6 Tests • Begin Chapter 7: “The Mole and Chemical Composition” • In-Class Assignments: • Practice pg. 228: #1-4 • Practice pg. 229: #1-4 • Concept Review: “Avo’s Number/Molar Conversions” • Homework: pg. 21/22 worksheet MUST SHOW WORK!

  2. Ch. 6 Tests“Covalent Compounds”

  3. Start Section 7.1: “Avogadro’s Number and Molar Conversions” • Atoms, ions, and molecules are very small, so even tiny samples have huge numbers of particles. • Scientists use the mole to make counting such large numbers easier. • Mole: the SI unit for amount; the number of atoms in exactly 12 grams of carbon-12.

  4. The Mole is a Counting Unit • The mole is used to count out a given number of particles, whether they are atoms, molecules, formula units, ions, or electrons. • The mole is just one kind of counting unit: • 1 dozen = 12 objects • 1 roll = 50 pennies • 1 hour = 3,600 seconds • 1 pair = 2 items • 1 mole = 6.022  1023 particles

  5. Avogadro’s Number & the Mole • The number of particles in a mole is called Avogadro’s Number. • Avogadro’s number is 6.022  1023; the number of atoms or molecules in 1.000 mole • Lorenzo Romano Amedeo Carlo Avogadro Born in Turin, Italy, on August 9th, 1776.

  6. Conversion Factors are Equivalent to 1 • The definition of one mole is: 6.022  1023 particles = 1 mol • From this definition, we get 2 conversion factors: 6.022 X 1023 particles = 1 1 mol _____1 mol________ = 1 6.022 X 1023 particles

  7. Use the Conversion Factor that Cancels Out the Known Units • Because a conversion factor is equal to 1, it can multiply any quantity without changing the value. • Only the units are changed. • When solving problems, the unit that you know goes on the bottom of the fraction.

  8. You Can use Conversion Factors to Change from One Unit to Another(Dimensional Analysis) Example #1: How many eggs are there in 5 dozen? • Start with what you know: 5 dozen • Multiply by a conversion factor to change dozen number of eggs: • 5 dozen X 12 eggs = 60 eggs 1 dozen

  9. You Can use Conversion Factors to Change from One Unit to Another(Dimensional Analysis) Example #2: If you have 548 plain white socks, how many pairs can you make? 1. Start with what you know: 548 socks • Multiply by a conversion factor to change socks pairs of socks: • 548 socks X 1 pair = 2 socks 274 pairs

  10. Changing Moles ParticlesSample Problem A, pg 228 Find the number of molecules in 2.5 mol of sulfur dioxide, SO2. • Start with what you know: 2.5 mol SO2 • Multiply by a conversion factor to change moles molecules: • 2.5 mol SO2 X 6.022 X 1023 molecules SO2 = 1 mole SO2 1.5 X1024 (2 sig figs) molecules SO2

  11. Changing Moles Particles Practice #1 How many particles are there in 2.45 X 10-6 mol of nickel, Ni(II) selenide, NiSe? • Start with what you know: 2.45 X 10-6 mol NiSe • Multiply by conversion factor to change moles particles: • 2.45 X 10 -6 mol NiSe X 6.022 X 1023 particles NiSe = 1 mole NiSe 1.48 X 1018 particles (3 sig figs)NiSe

  12. Changing Moles Particles Practice #2 How many atoms are there in 4.3 moles of tungsten, W? • Start with what you know: 4.3 moles W • Multiply by conversion factor to change moles atoms: • 4.3 mol W X 6.022 X 1023 atoms W = 1 mol W 2.6 X 1024 atoms W (2 sig figs)

  13. So far, we’ve been changing moles particles Do you think we can go the other way, and change particles moles? Of course we can, and that’s what we’re going to do!

  14. Changing Particles MolesSample Problem B, pg. 229 A sample contains 3.01 X 1023 molecules of sulfur dioxide, SO2. Determine the amount in moles. 1. Start with what you know: 3.01 X 1023 molecules SO2 • Multiply by conversion factor to change molecules moles: • 3.01 X 1023 molecules SO2 X __1 mole SO2______ 6.022 X 1023 molecules SO2 0.500 mole SO2 (3 sig figs)

  15. Changing Particles Moles Practice #1 How many moles are equivalent to 6.93 X 1023 thallium atoms, Tl? 1. Start with what you know: 6.93 X 1023Tl atoms • Multiply by conversion factor to change atoms moles: • 6.93 X 1023Tl atoms X 1 mole Tl = 6.022 X 1023Tl atoms (3 sig figs) 1.15 mole Tl

  16. Changing Particles Moles Practice #2 How many moles are equivalent to 7.95 X 1024 copper (II) chloride, CuCl2, formula units? 1. Start with what you know: 7.95 X 1024 CuCl2 formula units • Multiply by conversion factor to change formula units moles: • 7.95 X 1024 form. unit CuCl2 X ____1 mole_CuCl2___ 6.022 X 1023 form. unit CuCl2 13.2 mol CuCl2 (3 sig figs)

  17. In-Class Assignments/Homework • Practice pg. 228: #1-4 • Practice pg. 229: #1-4 Homework: • Practice Worksheets, pg. 21/22 • Concept Review: Avogadro’s Number and Molar Conversions” #1-5 You must SHOW WORK to get credit!

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