Moles and Molar Mass

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					         Chapter 9



           The Mole
Calculations Using Molar Mass




          Timberlake LecturePLUS   1
          Collection Terms

1 trio                   =         3 singers

1 six-pack Cola          =         6 cans Cola drink

1 dozen donuts           =         12 donuts

1 gross of pencils       =         144 pencils


                  Timberlake LecturePLUS           2
           A Mole of Particles


Contains 6.02 x 1023 particles


1 mole C       = 6.02 x 1023 C atoms
1 mole H2O     = 6.02 x 1023 H2O molecules
1 mole NaCl    = 6.02 x 1023 Na+ ions and
                  6.02 x 1023 Cl– ions
                  Timberlake LecturePLUS     3
      More Examples of Moles

Moles of elements
1 mole Mg     = 6.02 x 1023 Mg atoms
1 mole Au     = 6.02 x 1023 Au atoms
Moles of compounds
1 mole NH3    = 6.02 x 1023 NH3 molecules
1 mole C9H8O4 = 6.02 x 1023 aspirin molecules
                 Timberlake LecturePLUS     4
Avogadro's Number

6.02 x 1023 particles
   1 mole
           or

      1 mole
6.02 x 1023 particles

       Timberlake LecturePLUS   5
          Learning Check M1
Suppose we invented a new collection unit
called a mep. One mep contains 8 objects.
A. How many paper clips in 1 mep?
   1) 1            2) 4                 3) 8
B. How many oranges in 2.0 meps?
   1) 4            2) 8                 3) 16
C. How many meps contain 40 gummy bears?
   1) 5            2) 10                3) 20
               Timberlake LecturePLUS           6
             Solution M1

Suppose we invented a new collection unit
called a mep. One mep contains 8 objects.
A. How many paper clips in 1 mep?
   3) 8
B. How many oranges in 2.0 meps?
   3) 16
C. How many meps contain 40 gummy bears?
   1) 5
               Timberlake LecturePLUS   7
        Learning Check M2
1. Number of atoms in 0.500 mole of Al
  1) 500 Al atoms
  2) 6.02 x 1023 Al atoms
  3) 3.01 x 1023 Al atoms
2.Number of moles of S in 1.8 x 1024
  S atoms
  1) 1.0 mole S atoms
  2) 3.0 mole S atoms
  3) 1.1 x 1048 mole S atoms
               Timberlake LecturePLUS    8
               Solution M2
1. Number of atoms in 0.500 mol of Al
  3) 3.01 x 1023 Al atoms
   0.500 mol Al x 6.02 x 1023 Al atoms
                       1 mol Al

2. Number of moles of S if a sample of S
  contains 4.50 x 1024 S atoms
  2) 3.0 mole S atoms
  4.50 x 1024 S atoms x    1 mol S
                         6.02 x 1023 S atoms
                  Timberlake LecturePLUS       9
                Molar Mass
   Number of grams in 1 mole
   Equal to the numerical value of the atomic
    mass
       1 mole of C atoms                   =   12.0 g
       1 mole of Mg atoms                  =   24.3 g
       1 mole of Cu atoms                  =   63.5 g


                  Timberlake LecturePLUS                10
         Learning Check M3

Give the molar mass to 0.1 g
A. 1 mole of Br atoms                     =   ________


B. 1 mole of Sn atoms                     =   ________




                 Timberlake LecturePLUS              11
              Solution M3

Give the molar mass to 0.1 g
A. 1 mole of Br atoms =                   79.9 g/mole
B. 1 mole of Sn atoms =                   118.7 g/mole




                 Timberlake LecturePLUS                  12
     Molar Mass of Compounds
Mass in grams of 1 mole equal numerically to
the sum of the atomic masses
1 mole of CaCl2     = 111.1 g/mole
1 mole Ca x 40.1 g/mole
                   + 2 moles Cl x 35.5 g/mole

1 mole of N2O4     = 74.0 g/mole
2 moles N x 14.0 g/mole
              + 4 moles O x 16.0 g/mole
                  Timberlake LecturePLUS        13
          Learning Check M4


A. 1 mole of K2O                            = ______g




B. 1 mole of antacid Al(OH)3                = ______g



                   Timberlake LecturePLUS               14
               Solution M4


A. 1 mole of K2O                            = 94.2 g
   2 K x 39.1 g/mole + 1 O x 16.0 g/mole


B. 1 mole of antacid Al(OH)3                = 78.0 g
  1 Al x 27.0 g/mole + 3 O x 16.0 g/mole
 + 3 x 1.0
                   Timberlake LecturePLUS          15
       Learning Check M5

Prozac, C17H18F3NO, is a widely used
antidepressant that inhibits the uptake of
serotonin by the brain. It has a molar mass
of
1) 40.0 g/mole
2) 262 g/mole
3) 309 g/mole

                 Timberlake LecturePLUS   16
             Solution M5

Prozac, C17H18F3NO, is a widely used
antidepressant that inhibits the uptake of
serotonin by the brain. It has a molar mass
of
3) 309 g/mole
17C (12.0) + 18H (1.0) + 3F (19.0) + 1N (14.0)
+ 1 O (16.0)

                Timberlake LecturePLUS     17
      Learning Check M6

What is the percent carbon in C5H8NO4
(MSG monosodium glutamate), a
compound used to flavor foods and
tenderize meats?
1) 8.22 %C
2) 24.3 %C
3) 41.1 %C

              Timberlake LecturePLUS    18
            Solution M6

Molar mass = 146.0 g/mole
% = total g C          x 100
    total g compound

 = 60.0 g C        x 100 = 41.1% C
  146.0 g MSG



             Timberlake LecturePLUS   19
   Molar Mass Factors for CH4
Methane CH4 known as natural gas is used
in gas cook tops and gas heaters. Express
the molar mass of methane in the form of
conversion factors.

Molar mass of CH4 =          16.0 g

16.0 g CH4     and                  1 mole CH4
1 mole CH4                         16.0 g CH4

               Timberlake LecturePLUS            20
        Learning Check M7

Acetic acid CH3COOH is the acid in vinegar . It
has a molar mass of 60.0 g/mole.


1 mole of acetic acid           =        ____________

1 mole acetic acid        or             g acetic acid
     g acetic acid                   1 mole acetic acid


                Timberlake LecturePLUS                  21
              Solution M7

Acetic acid CH3COOH is the acid in vinegar . It
has a molar mass of 60.0 g/mole.


1 mole of acetic acid           =        60.0 g

1 mole acetic acid        or         60.0 g acetic acid
60.0 g acetic acid                   1 mole acetic acid


                Timberlake LecturePLUS              22
Calculations with Molar Mass


          molar mass
  Grams                            Moles




          Timberlake LecturePLUS           23
          Moles and Grams

Aluminum is often used for the structure of
light-weight bicycle frames. How many grams
of Al are in 3.00 moles of Al?

   3.00 moles Al              ? g Al




                   Timberlake LecturePLUS   24
1. Molar mass of Al
          1 mole Al = 27.0 g Al
2. Conversion factors for Al
   27.0g Al     or    1 mol Al
   1 mol Al           27.0 g Al

3. Setup
  3.00 moles Al x     27.0 g Al
                      1 mole Al

          Answer           = 81.0 g Al
                    Timberlake LecturePLUS   25
      Learning Check M9

The artificial sweetener aspartame
(Nutri-Sweet) formula C14H18N2O5 is
used to sweeten diet foods, coffee and
soft drinks. How many moles of
aspartame are present in 225 g of
aspartame?


             Timberlake LecturePLUS      26
                Solution M9

1. Molar mass of Aspartame C14H18N2O5
 (14 x 12.0) + (18 x 1.01) + (2 x 14.0) + (5 x 16.0)
                             = 294 g/mole
2. Setup
  225 g aspartame x 1 mole aspartame
                     294 g aspartame

                         = 0.765 mole aspartame

                   Timberlake LecturePLUS         27

				
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