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The Mole

‘ 09. You WILL NEED your calculators from now on!!. The Mole. A Counting Unit. Rev 10/12/09. Other Counting Units. 1 Dozen =12 things 1 Pair =2 things 1 Gross = 144 things ( a dozen dozens ). 1 mole (mol)=.

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The Mole

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  1. ‘ 09 You WILL NEED your calculators from now on!! The Mole A Counting Unit Rev 10/12/09

  2. Other Counting Units • 1 Dozen =12 things • 1 Pair =2 things • 1 Gross = 144 things (a dozen dozens)

  3. 1 mole (mol)= Yes, we do abbreviate a 4 letter word with a 3 letter word – but not just me – the whole world does! • 602,000,000,000,000,000,000,000 things • = 6.02 x 1023 things • What could you possibly measure that is made up of so many things?

  4. Random FYI… • If you had a mole’s worth of rice (meaning 6.02 x 1023 grains of rice, it would weigh just as much as if EVERY PERSON on the planet had a MILLION cars!!!!! • So why in the WORLD would we want to work with such a HUGE quantity? Because atoms are so small!!!!

  5. Moles are used to represent very small particles like the number of: Moles enable chemists to “count by weighing” • Atoms • Molecules • Formula units Now remember our rice story… every person with a million cars… now think about that same amount of hydrogen… guess how much it might weigh… H2=2 grams!

  6. Representative Particles Atoms– any element from Periodic Table Ex. C, Sc, Sb Molecules– 2 or more non-metals chemically combined Ex. H2O, CO2, NH3 Formula units –a metal + nonmetal combined Ex. NaCl, BeO, FeI3

  7. 1 mole of an atom = • It’s mass on periodic table • For example: 1 mole Carbon = 12.01 g 1 mol C = ? Atoms C • 12.01 grams of Carbon = ? atoms 6.02 x1023 atoms Reminder: 1 ATOM of C weighs 12.01 amu’s.

  8. What is the molar mass? The mass of the mole, silly! • Copper (Cu) 63.55g = 1 mol Cu • Oxygen (O2) 16.00g per mol of O…but… 32.00g = 1 mol O2

  9. What is the molar mass? • Copper II Oxide (CuO) (What’s the roman numeral mean? Why II?) 63.55g /mol Cu + 16.00g /mol O 79.55g /mol CuO • You try Ammonium nitrate, NH4NO3 2 (14.0) g/ mol N 4 ( 1.0) g/ mol H + 3 (16.0) g/ mol O 80g/mol

  10. Dimensional Analysis • Conversion factors can be used to convert units • 12.01 g = 1 mol C • 3.85 mol C would have a mass of what? 3.85 mol C (12.01g C) = 46.2 g C 1 (1 mol C)

  11. 3.2 mol of malachite,Cu2CO3(OH)2 is how many grams? • 1 mol= 221.13 g 3.2 mol 1 = 708 g Malachite (221.13g malachite) (1 mol malachite)

  12. REVIEW o rmu l a n i t s 1 mol = 6.02 x 1023IAMFU o l ecu l e s ons t oms • 1 moleNH4+ = 6.02 x 1023 ionsNH4+ .1 moleNaCl = 6.02 x 1023 formula units ofNaCl • 1 moleAu = 6.02 x 1023 atoms Au • 1 moleCO2 = 6.02 x 1023 moleculesCO2 • 1 mole equals formula mass on periodic table • Mole to mole ratios of different substances are the coefficients in balanced equations • Coefficients in balanced equations are NOT gram to gram ratios, must first convert to moles to use molar ratio

  13. To Do: Bring a piece of sugarful gum in the wrapper tomorrow.

  14. May the Mole be with you !!

  15. Mole Ratio’s in Balanced Equations Coefficients represent mole ratios 2CuO + C --> 2Cu + CO2 2 mol CuO / 1 mol CO2 How many moles of CuO is needed to produce 8 moles of CO2? 8 mol CO2 (2 mol CuO) Note: BOTH units cancel! (1 mol CO2) = 16 mol CuO

  16. Balanced 4NH3 + 7O2 --> 4NO2 + 6H2O How many moles of oxygen are needed to react with 200 moles of ammonia (NH3) 200mol NH3 (7mol O2) = 350mol O2 (4 mol NH3) • How many grams of O2 is that equal to? 350 mol O2 (32 g O2) = 11,200 g O2 (1 mol O2)

  17. Practice: Calculate Reactant mass & Product mass NH3 + O2 --> NO2 + H2O • 17g 32g 46g 18g • 49g  64g So what do we need to do? Balance the equation • 4NH3 + 7O2 --> 4NO2 + 6H2O • 68 g 224g 184g 108g • 292g = 292g

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