Types of Chemical Reactions Lab
DISCUSSION & OBJECTIVE:
   Chemical reactions are sometimes classified into several broad categories.  This classification is by no means intended to include every individual reaction.  The benefit of studying reactions in classes is to assist you in learning what to predict about the outcome of a reaction.
    In this lab, you will examine several types of reactions including single replacement, double replacement, and decomposition reactions.  Please keep accurate records of the reactions and their products.

MATERIALS (EQUIPMENT):
- test tubes (6)               - test tube rack              - stirring rod                  - wood splints (4)           - matches
- funnel                          - filter paper (2)             - ring stand                    - iron ring                      - wire gauze
- 250 mL beaker ((2)       - lab burner                   - beaker tongs

MATERIALS (CHEMICALS):
SOLIDS:                       
            - zinc                            - iron                            - copper                        - MnO2

AQUEOUS SOLUTIONS:  
            - CuSO4                             - NaOH*                        - H2SO4*                        - FeSO4             - H2O2*          
* dropper pipets included

PROCEDURES:           
A.  Double Replacement
1.  Label test tubes 1, 2, 3, 4, 5, and 6.
2.  Place about 5 mL of CuSO4 solution in test tube 1.  (The CuSO4 should be added until it is about the height of
     your thumb nail.) Then, add 4 drops of NaOH solution.
3.  Let the test tube stand until the solid has stopped forming.  At this point, you will need to ask your instructor
     to put your test tube in the centrifuge.  (The purpose of putting your test tube in the centrifuge is to collect all
     of the solid that has formed at the bottom of the test tube.)
     The solid formed is called a precipitate.  Decant the solution remaining in the test tube.  This simply means to
     carefully pour the liquid on top of the precipitate into test tube 2.  The centrifuge should help the precipitate
     remain at the bottom of the test tube.  The liquid poured off is called the supernatant.
4.  Add 3 or 4 drops of NaOH to the supernatant liquid from above.  Observe.

B.  Single Replacement (replacement of hydrogen)
1.  Place a small piece of zinc in test tube 3.  Add enough H2SO4.to cover the piece of zinc.  CAUTION!  H2SO4
     is sulfuric acid.  It can cause severe burns.  Use caution when handling any equipment that
     contains H2SO4.
2.  Hold your thumb over the open end of the test tube for about 1 to 2 minutes.  (You may have to hold your
     thumb over the end of the test tube for less than 1 minute or more than 2 minutes.  You will feel pressure
     begin to push on your thumb.  When that pressure builds up, then you should go on to step 3.) 
3.  Place a burning wood splint into the open end of the test tube.  (Make sure that you keep your thumb over
     the end of the test tube until you are ready to put the wood splint near the end of the tube.)  Observe.
4.  Let the test tube stand until there is no more Zn or until the reaction has stopped as evidenced by no further
     bubbling.  Filter the solution into a 250 mL beaker to prevent any unreacted Zn from getting into the beaker.
     Once the liquid has finished draining through the filter paper, throw the filter paper and its contents in the
     trash.  (Please note that trash does not belong in the sink!)
5.  Place the 250 mL beaker with the solution on the ring stand (with the wire gauze on it) and heat it gently!
     (You will not get accurate results if you heat the solution too quickly.  Use a SMALL flame.)
     When most of the solution has evaporated, and the crystal is nearly dry, remove from the heat.  Observe.
6.  Obviously, the crystal formed was dissolved in water to begin with.  To test for solubility after the evaporation,
     allow the beaker to cool (go on to Part C), and later add water and stir to determine if the solid is still soluble.

 

C.  Single Replacement
1.  Place about 5 mL of CuSO4 solution (thumb nail height) in test tube 4 and add 7 drops of H2SO4.  Carefully
     add about 5 small scoops of iron (as much iron as you can collect on the end of an unused wood splint) into
     test tube 4.  The acid (H2SO4) is a catalyst.  Use caution when handling acids.
2.  Let the setup stand for 5 minutes or so and then pour through a new piece of filter paper.  Once all of the
     liquid has drained through, open the filter paper and observe the solid.  You can pour the supernatant
     solution down the sink.

D. Single Replacement
1.  Place about 5 mL of FeSO4 solution (thumb nail height) in test tube 5 and add 7 drops of H2SO4.  Carefully
     add about 5 small scoops of copper (as much copper as you can collect on the end of a different unused
     wood splint) into test tube 5. 
2.  Let the setup stand for 5 minutes or so and then pour through a new piece of filter paper.  Once all of the
     liquid has drained through, open the filter paper and observe the solid.  You can pour the supernatant
     solution down the sink.

E. Decomposition
1.  Place 5 mL of H2O2 (hydrogen peroxide) in test tube 6 and observe.
2.  Carefully add a small amount of MnO2 to the H2O2.  You only need about as much as the end of a wood splint
     will hold.
3.  Note the changes that occur after adding the MnO2.  (Please note that MnO2 is NOT chemically changed as a
     result of the reaction.  It is a catalyst.  It simply speeds up the rate of the reaction.)   

Link to the Data Chart and Questions for this lab