Lab Mole Ratios and Reaction Stoichiometry by shitingting

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									Lab Mole Ratios and Reaction                       Name_______________________Period______

Purpose: To experimentally determine the mole-to-mole ratios between the reactants and products in the
following double displacement “gas forming” reactions and calculate percent yield of the reaction.

Background
[Explain step by step on how to find mole ratio and why we use it]
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Materials:
sodium bicarbonate (NaHCO3)                 wire gauze                   stand and ring clamp
1M hydrochloric acid (HCl)                  evaporating dish             small beaker
vinegar (CH3COOH)                           watch glass                  dropper pipette
balance (scale)                             Bunsen burner                tongs

Procedure:
   1. Weight the mass of your clean dry evaporating dish + watch
       glass. Record under Reaction #1 column
   2. Carefully add about 0.5 g of sodium bicarbonate (NaHCO3)
       to the evaporating dish. Record the mass of the evaporating
       dish + watch glass + NaHCO3.
   3. Pour some vinegar (acetic acid) in to a small beaker and use
       the pipette to add the vinegar drop by drop to the sodium
       bicarbonate in the evaporating dish
   4. Continue adding vinegar until the bubbling stops
   5. Cover the evaporating dish with the watch glass and place it
       on the wire gauze.
   6. Gently heat the solution in the covered evaporating dish with
       a Bunsen burner flame in order to remove the water
   7. Continue heating until the contents are completely dry.
       Watch glass cover should also be dry!
   8. Turn off the Bunsen burner when not in use
   9. Allowing the evaporating dish to cool to room temperature before putting it on the scale. Weight the
       mass of the evaporating dish + watch glass + residue (CH3COONa).
   10. Repeat steps 1 to 9 with a HCl (hydrochloric acid instead of vinegar) and record in trial #2 column
   11. The waste from this experiment may not be disposed of in the sink.

Data
                                      Reaction #1 (vinegar)                Trial #2 (HCl)
Mass of evaporating dish + watch
glass
Mass of evaporating dish + watch
glass + NaHCO3
Mass of NaHCO3

                                   Data after evaporation under Bunsen burner
Mass of evaporating dish + watch
glass + white residue
Mass of white residue alone


Analysis Questions:
1. What happen to the excess liquid that you added in both reactions? _________________________________

2. Balance the following equations:
Reaction #1: sodium bicarbonate +     acetic acid → sodium acetate + carbon dioxide + water
               ________ NaHCO3 + _____CH3COOH → __ CH3COONa + ________ CO2+ ___ H 2O

Reaction #2: sodium bicarbonate + hydrochloric acid → sodium chloride + carbon dioxide + water
             ______ NaHCO3 (s) + _______ HCl (aq) → ____ NaCl (aq) + _____ CO2 (g) + ___ H2O (l)

3. What is the solid compound that’s left in your dish in reaction #1 ____________and reaction #2___________

4. What is the mole ratio between NaHCO3 and CH3COONa _________________________________________

5. What is the mole ratio between NaHCO3 and NaCl ______________________________________________

6. If you started with 1 mole of baking soda how many moles of the solid product should have been produced?
        Reaction #1 _______________                Reaction #2______________

7. If you started with 5 moles of baking soda how many moles of the solid product should have been produced?
        Reaction #1 _______________                Reaction #2______________

6. How many moles is 1 gram of NaHCO3 (baking soda)? (show work with the picket fence method)




7. Compare the mass of your reactant (NaHCO3) with your product for both reactions. Do they have the same
mass after they reacted? Why or why not? _______________________________________________________
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8. Based on the balance equation if you started with 1 gram of baking soda how many grams of CH3COONa
and how many grams of NaCl do you expect to get? (theoretical yield)




9. What is the actual yield for CH3COONa and NaCl? Find the percent yield for reaction #1 and #2




10. If you want to produce 10 moles of NaCl. How many grams of NaHCO3should you start with?

								
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