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					Ch. 10 – The Mole




   I. Molar Conversions



               I    II   III   IV
A. What is the Mole?

   A counting number (like a dozen)




   Avogadro’s number (NA)

   1 mole = 6.022  1023 representative
    particles
A. What is the Mole?


   1 mole of eggs would fill all the
    oceans on Earth…more than 30
    million times!
   1 mole of basketballs would fill a
    bag the size of the earth!

   1 mole of pennies would cover
    the Earth ¼ mile deep!
B. Mole/Particle Conversions
          6.022  1023
              NA
                            NUMBER
MOLES                          OF
                           PARTICLES

        (particles/mol)      Particles =
         NA atoms/mol          atoms,
                             molecules,
        NA molecules/mol   formula units,
                              ions, etc
B. Mole/Particle Conversion Examples

 How many molecules are in
 2.50 moles of C12H22O11?

2.50 mol    6.02  1023
            molecules
C12H22O11
            C12H22O11
                          = 1.51  1024
            1 mol
              C12H22O11     molecules
                            C12H22O11
B. Mole/Particle Conversion Examples

 Ifyou have 2.23 x 1018 atoms of
  sodium, how many moles is
  that?


2.23  1018 1 mole Na
atoms Na                   3.70 x 10-6
           6.02  1023   = moles Na
           atoms Na
 B. Mole/Particle Conversion Examples

  How many formula units is 3.75
   moles of calcium hydroxide?

            6.02  1023
    3.75    formula units
mol Ca(OH)2 Ca(OH)2
                         = 2.26  1024
             1 mol Ca(OH)2 formula units
                           Ca(OH)2
C. Molar Mass
   Avogadro discovered the
    relationship between number of
    particles and volume of a gas
   This was used to find the
    relationship for particles in a mole
 Representative Particles & Moles

Substance Chemical Representative Rep Particles
          Formula     Particle    in 1.00 mole
  Carbon       C        Atom         6.02 x 1023

 Nitrogen
    gas
               N2      Molecule      6.02 x 1023

Calcium ion   Ca2+       Ion         6.02 x 1023

Magnesium
 fluoride
              MgF2   Formula unit    6.02 x 1023
C. Molar Mass
   Mass of 1 mole of an element or
    compound

   Atomic mass (on the PT) tells the...
     mass of each atom (amu)
     grams per mole (g/mol)
   Round to 2 decimal places
C. Molar Mass Examples

   carbon     12.01 g/mol


   aluminum   26.98 g/mol


   zinc       65.39 g/mol
C. Molar Mass Examples

   water
     H2O
     2(1.01) + 16.00 = 18.02 g/mol

   sodium chloride
      NaCl
      22.99 + 35.45 = 58.44 g/mol
C. Molar Mass Examples

   sodium bicarbonate
     NaHCO3
     22.99 + 1.01 + 12.01 + 3(16.00)
                     = 84.01 g/mol
   sucrose
      C12H22O11
      12(12.01) + 22(1.01) + 11(16.00)
                      = 342.34 g/mol
C. Molar Mass Examples

   magnesium hydroxide
     Mg(OH)2
     24.31 + 2(16.00) + 2(1.01)
                   = 58.33 g/mol
 ammonium sulfate
   (NH4)2SO4
   2(14.01) + 8(1.01) + 32.06 +
    4(16.00)       = 132.16 g/mol
      D. Molar Conversions

        molar             6.02  1023
        mass                  NA
MASS                                          NUMBER
 IN               MOLES                           OF
GRAMS                                       PARTICLES
        (g/mol)           (particles/mol)
                                            Particles = atoms,
                                            molecules, formula
                                             units, ions, etc
                          NA atoms/mol

                      NA molecules/mol
D. Molar Conversion Examples
 Howmany moles of carbon
 atoms are in 26 g of carbon?


 26 g C 1 mol C
                     = 2.2 mol C
         12.01 g C
D. Molar Conversion Examples
 Findthe mass of 2.1  1024
 molecules of NaHCO3.
 2.1  1024
 Molecules 1 mol         84.01 g
 NaHCO3      NaHCO3       NaHCO3
           6.02  1023 1 mol
           Molecules     NaHCO3
             NaHCO3
                = 290 g NaHCO3
D. Molar Conversion Examples
 Howmany moles are in 22.5
 grams of potassium?

                      6.02  1023
22.5 g K    1 mol K   atoms K
           39.10 g K 1 mol K

           = 3.46 x 1023 atoms K

				
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posted:9/22/2012
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