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CHEMICAL QUANTITIES

CHEMICAL QUANTITIES. The Mole. If we had to count the atoms of Silicon and Oxygen in this sand sculpture? What unit would we use? Gram? No! Kilograms? No!. The Mole.

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CHEMICAL QUANTITIES

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  1. CHEMICAL QUANTITIES The Mole

  2. If we had to count the atoms of Silicon and Oxygen in this sand sculpture? What unit would we use? Gram? No! Kilograms? No! The Mole

  3. The “MOLE” is a specialized unit for measuring amounts of matter as molecules, formula units, atoms, ions, and subatomic particles. 1 mole is defined as 6.0221415×1023 For the purposes of this class 1 mole = 6.02 × 1023

  4. The “MOLE” is counting unit like “1 dozen = 12” or “1 gross = 12 dozen”…1 mole = 6.02 x 1023 1 mole of bagels = 6.02 x 1023 bagels 1 mole of bicycles = 6.02 x 1023 bicycles 1 mole of people = 6.02 x 1023 people

  5. Some Other Specialized Units 1 dozen = 12 Used to measure eggs, bagel, & donuts 1 carat = 200 milligrams Used to measure gems & precious stones or metals 1 acre = 1/640 of a mile2 Used to measure parcels of property 1 Ǻngstrom(Ǻ) = 10-10meters Used to measure atomic radii 1 hogshead = 1 kegs = 63 gallons Used to measure liquids: e.g. molasses, beer (see “Huck Finn”) 1 grain = 0.06479891 gram Used for precise measurements of metals, e.g. bullets

  6. Why this number? 6.02 x 1023 Recall that: 1 a.m.u. (atomic mass unit) is defined as 1/12 of the mass of a Carbon-12, (12C)atom; therefore the mass of one 12C atom equals 12 a.m.u. The mass of an Copper-63 (63Cu) equals 63 a.m.u. and the Average Atomic Mass of all isotopes on Copper equals: a.m.u. (–look it up on your Chemhelper) 63.55

  7. Why this number? 6.02 x 1023 Our scales measure mass in grams not a.m.u., wouldn’t it be nice if instead of 63.546 a.m.u. of Copper, we could talk about 63.546 grams of Copper. One number that works with both units: a.m.u. and grams.

  8. 6.02 x 1023Avogadro’s Number But, how many atoms of Copper are present in a sample that has a mass of 63.55 grams?

  9. NOTE: 6.02 x 1023 is known as Avogadro’s Number in honor of Amedeo Avogadro di Quaregna (1776-1856), who was a pioneer in the properties of gases 6.02 x 1023 a.m.u.s = 1 gram Remember 1 mole = 6.02 x 1023so…1 molea.m.u.s = 1 gram

  10. If you don’t already have it out, get out your Sargent-Welch PTOE for immediate use.

  11. How do we used the mole? GAM  gram atomic mass 79 Au Gold 196.97 See Chemhelper 1 gold atom has a mass of 196.97 a.m.u. 1 mole of gold atoms have a gram atomic mass (GAM) of 196.97 grams

  12. What is the Gram Atomic Mass of… 88 Ra Radium

  13. What is the Gram Atomic Mass of… 88 Ra Radium 226.02 grams per mole (g/mol)

  14. What is the Gram Atomic Mass of… 88 Ra Radium 226.02 grams per mole (g/mol) As Arsenic

  15. What is the Gram Atomic Mass of… 88 Ra Radium 226.02 grams per mole (g/mol) As Arsenic 74.92 grams per mole (g/mol)

  16. Gram Formula Mass (GFM) Vs.Gram Molar Mass (GMM)What is the difference? Recall: There are two types of compounds that you learned to name: Molecular and Ionic. Molecular Compounds form Molecules, which have a Gram Molar Mass Ionic Compounds form a Formula Units, which have a Gram Formula Mass

  17. Calculating an Ionic Compounds’ Gram Formula Mass (Ex 1- Lithium Fluoride) GFM for LiF =

  18. Calculating an Ionic Compounds’ Gram Formula Mass (Ex 1) GFM for LiF =

  19. Calculating an Ionic Compounds’ Gram Formula Mass (Ex 1) GFM for LiF =

  20. Calculating an Ionic Compounds’ Gram Formula Mass (Ex 1) GFM for LiF =

  21. Calculating an Ionic Compounds’ Gram Formula Mass (Ex 1) GFM for LiF =

  22. Calculating an Ionic Compounds’ Gram Formula Mass (Ex 1) GFM for LiF =

  23. Calculating an Ionic Compounds’ Gram Formula Mass (Ex 1) GFM for LiF =

  24. Calculating an Ionic Compounds’ Gram Formula Mass (Ex 1) 25.94-g/mol GFM for LiF =

  25. Calculating an Ionic Compounds’Gram Formula Mass (Ex 2-Sodium Oxide) GFM for Na2O =

  26. Calculating an Ionic Compounds’Gram Formula Mass (Ex 2) GFM for Na2O =

  27. Calculating an Ionic Compounds’Gram Formula Mass (Ex 2) GFM for Na2O =

  28. Calculating an Ionic Compounds’Gram Formula Mass (Ex 2) GFM for Na2O =

  29. Calculating an Ionic Compounds’Gram Formula Mass (Ex 2) 61.98-g/mol GFM for Na2O =

  30. Calculating an Ionic Compounds’Gram Formula Mass (Ex 3-Chromium(III) Sulfate) GFM for Cr2(SO4)3 =

  31. Calculating an Ionic Compounds’Gram Formula Mass (Ex 3-Chromium(III) Sulfate) GFM for Cr2(SO4)3 =

  32. Calculating an Ionic Compounds’Gram Formula Mass (Ex 3-Chromium(III) Sulfate) GFM for Cr2(SO4)3 =

  33. WHOA! Cr2(SO4)3 : think “Distributive Property” • 2 Cr3+ ions: chromium (III) ions • 3 S2- ions: sulfide ions • 12 O atoms: oxygen atoms Cr2(S1x3 O4x3) =

  34. Calculating an Ionic Compounds’Gram Formula Mass (Ex 3-Chromium(III) Sulfate) GFM for Cr2(SO4)3 =

  35. Calculating an Ionic Compounds’Gram Formula Mass (Ex 3-Chromium(III) Sulfate) 392.1-g/mol GFM for Cr2(SO4)3 =

  36. (Ex 4-Ammonium Sulfite) GFM for (NH4)2SO3 =

  37. (Ex 4-Ammonium Sulfite) 116.16-g/mol GFM for (NH4)2SO3 =

  38. That was GFM—Gram Formula Mass…nowHere’s GMM—Gram Molar Mass

  39. Calculating a Molecular Compounds’Gram Molar Mass GMM (Ex 1: S2O4) GMM for S2O4 =

  40. Calculating a Molecular Compounds’Gram Molar Mass GMM (Ex 1: S2O4) GMM for S2O4 =

  41. Calculating a Molecular Compounds’Gram Molar Mass GMM (Ex 1: S2O4)Disulfur Tetroxide GMM for S2O4 = 128.12-g/mol

  42. What’s the difference? There is no difference in the process of calculating GMM--Gram Molar Masses-- and GFM--Gram Formula Masses. The differing terminology reflects the two different types of compounds: molecular compounds and ionic compounds.

  43. THE END HaHa

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