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What-is-Stoichiometry

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What-is-Stoichiometry Powered By Docstoc
					 INDIVIDUAL BRAINSTORM: Silently,
 make a list of the best places to get a
 burger. (1 minute)
 GROUP BRAINSTORM: Rank the top three
 places to get a burger. What made the
 burger so great? (2 minutes)
A   burger “recipe” might look like this:
         1 Bu + 2 Hb + 1 Ch + 4 Ba     1 Ub
 Asa group, develop your ultimate burger recipe
 and write it as an equation. Here are the
 available ingredients:
   Using the ingredients handout from Ms.
    Brown, answer these questions:
    1. How many complete burgers can you make?
    2. Which ingredient(s) is/are completely used
       up?
    3. How much of each leftover ingredient remains
       unused?
    4. List and explain the steps that your group used
       to answer the questions above.
   Now, write three (3) problems and their
    solutions based on your burger recipe.
   Example: If Annie has 18 strips of bacon, how
    many burger patties does she need to
    completely use up her bacon?
         1 Bu + 2 Hb + 1 Ch + 4 Ba     1 Ub

            18 Ba       2 Hb
                                 = 9.0 Hb
                        4 Ba
 Your ultimate burger recipe
 Your answers to the 4 questions
 Your three problems with solutions
 Your group answers to these reflection
 questions:
    1. How well did your group come to consensus
       today? Explain.
    2. What do you think that this activity has to do
       with chemistry content?
    3. Are you hungry right now?
[stoy-key-AH-meh-tree]
   DEFINITION: calculation of quantities in
    reactions
   KEY STEP: mole ratio from balanced
    equation
   So, to do stoichiometry, you need a
    balanced equation!
    N2          +       3 H2             2 NH3
1 molecule N2   +   3 molecules H2    2 molecules NH3

 1 mole N2      +     3 moles H2        2 moles NH3

                    3(2.016) g H2 =   2(17.0343) g NH3
 28.02 g N2     +
                      6.048 g H2       = 34.068 g NH3
4 Fe   +   3 O2   2 Fe2O3
       +

       +


       +
   Ratio between the numbers of moles of
    any two substances in a balanced
    chemical equation
   Example: 2 KClO3      2 KCl + 3 O2
   How many moles of oxygen gas can be
    produced by the reaction of 5.85 moles of
    potassium chlorate?
            2 KClO3     2 KCl + 3 O2
   How many liters of oxygen gas at STP can
    be produced by the reaction of 47.9
    grams of potassium chlorate?
           2 KClO3      2 KCl + 3 O2
rep. particles A                                       rep. particles B



       grams A     mole A                     mole B   grams B
                            use mole ratio!


        liters A                                       liters B
   How many liters of oxygen gas at STP can
    be produced by the reaction of 47.9
    grams of potassium chlorate?
           2 KClO3      2 KCl + 3 O2

				
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