MOLES!!! by 8VdW3t

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									MOLES!!!

•   more molar ratios
•   mass – mass conversions
MOLES!!!




 6.02 X 1023
MORE MOLES!!!




   6.02 X 1023
MOLES 4LIFE!!!




                 6.02 X 1023
MASS - MASS CONVERSIONS
              Mg + O2  MgO

  If I start out with 50 grams O2, then how
       many grams of MgO will I produce?

What problems do I face here?
  •I need to convert from reactants to products!
  •Equation is not balanced!
  •Coefficients represent moles, not grams!
 MASS - MASS CONVERSIONS
     If I start out with 50 grams O2, then how many grams of
     MgO will I produce?

STEPS
1.   Balance the equation         1.   __Mg +__O2 __MgO

2.   Convert grams to moles       2.   50g O2 = ? mol O2

3.   Examine mole ratios          3.   ? mol O2  ? mol MgO
4.   Convert to desired units     4.   ? mol MgO  ? g MgO
     (moles to grams)
1) Balance the equation



   __Mg +__O2 __MgO
   2      1     2

 2) Convert grams to moles
 3) Examine mole ratios
 4) Convert to desired units (moles to grams)
1) Balance the equation
2) Convert grams to moles
       50g O2 = ? mol O2
  •How do you convert from grams to moles???
     •Find the MOLAR MASS!
     •1 mol O2 = 2(16.00)g = 32.00g
  •Now let’s solve the equation…

      • 50 g O2 |           1 mol O2             | 1.56 mol O2
                |           32.00 g O2           |
  3) Examine mole ratios
  4) Convert to desired units (moles to grams)
1) Balance the equation
2) Convert grams to moles

3) Examine mole ratios
                        1.56 mol O2  ? mol MgO

  Balanced Equation: 2 Mg + 1 O2  2 MgO
  1 mol O2  2 mol MgO


  Now let’s convert moles of oxygen into moles of
  magnesium oxide!

  •1.56 mol O2|             2 mol MgO | 3.12 mol MgO
              |             1 mol O2 |
  4) Convert to desired units (moles to grams)
1) Balance the equation
2) Convert grams to moles
3) Examine mole ratios

4) Convert to desired units
                   3.12 mol MgO  ? g MgO
    •How do you convert from moles to grams???
         •Find the MOLAR MASS!
         •1 mol MgO = 24.31 + 16.00 g = 40.31g MgO

    •Now let’s solve the equation…
       • 3.12 mol MgO |   40.31g MgO         | 125.77g MgO
                      |   1 mol MgO          |
MASS - MASS CONVERSIONS
If I start out with 50 grams O2, then how many
   grams of MgO will I produce?

                  2 Mg + 1 O2  2 MgO
      50 g O2 |   1 mol O2     | 1.56 mol O2
          |       32.00 g O2   |

  1.56 mol O2|    2 mol MgO    | 3.12 mol MgO
             |    1 mol O2     |

      3.12 mol MgO |     40.31g MgO    | 125.77g
      MgO
               | 1 mol MgO      |
MORE MOLAR RATIOS

Gases:
 1 mole of ANY gas =
  22.4L in volume at STP
 (standard temperature & pressure)

  1  mol CO2 = 22.4 L
   1 mol O2 = 22.4 L
   1 mol H2 = 22.4 L
SOLVE…
1)   What is the volume of 2.7 mol CO2?
        2.7 mol    | 22.4L    | 60.48L
                    | 1 mol    |


2)   A balloon is filled with 5L oxygen gas.
     How many moles is this?
        5L   | 1 mol     | 0.22 mol
              | 22.4L     |
MORE MOLAR RATIOS
MOLARITY
 Used to refer to
  concentration of
  solutions (usually in
  water)

   # moles
      liters
                          A 1.0 molar (1.0M) solution has 1 mole/L
                          A 5.0M solution has 5.0 moles/L
SOLVE…
1)       If you measure out 0.55L of a 6M solution of HCl, how
         many moles of HCl do you have?
          0.55L | 6 mol | 3.3 mol
                 |1 L    |


2)       If you need 0.7 mol NaOH for a reaction, how many
         liters do you need to take from a 3M solution?
          0.7 mol       |   1 L     | 0.23 L
                         |   3 mol   |

								
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