Reactions Lab 

TYPES OF CHEMICAL REACTIONS LAB

Background:  There are millions of chemical reactions that occur every day, and most of these occur inside your body to keep you alive. Despite the vast number of chemical reactions, most of these can be classified as five major types of reactions. These Reactions are:

1. COMBUSTION = The burning of a substance in the presence of oxygen.

2. SYNTHESIS (COMBINATION)= This results when two less complex substances combine to form a more complex substance.

3. DECOMPOSITION= This results when a more complex substance breaks down to form two or more les complex substances.

4. SINGLE DISPLACEMENT (REPLACEMENT) = This results when a single element in a compound (or a formal unit) replaces another element in a different compound (or formula unit).

5. DOUBLE DISPLACEMENT (REPLACEMENT) = This results when one more complex substance combine to form less complex substances.

PROCEDURE:                 rx 1,2

1. Place  5 ml of Hydrochloric Acid (HCl) in a test tube.

2. Cut three strips of magnesium ribbon about 2 cm long.

3. Add one strip to the acid.

4. Record results. (rx 1)

5. Add the remaining two strips.

6. Place the burning splint over the top of the test tube.(Maybe insert the splint into the test tube.)

7. Record the results. (rx 2)

8. Dispose of the contents in the test tube as directed by the teacher.

9. Rinse test tube with distilled water.

rx 3,4

1. Use the scoop spatula and obtain a pea size of Manganese dioxide (MnO2) in a test tube.(Serves as a catalyst.)

2. Add 10 ml of hydrogen peroxide (H2O2) to the test tube with the MnO2. (Have a glowing splint ready.)

3. Record results. (rx 3)

4. Quickly insert the glowing splint into the test tube. *Do NOT put the splint into the liquid!

5. Record the results. (rx 4)

6. Dispose of the contents in the test tube as directed by the teacher.

7. Rinse test tube with distilled water.

Demonstration.(Not needed for the lab write-up.) DO NOT DO THIS ONE!  TEACHER ONLY!!

1. Obtain about 6 cm of magnesium ribbon.

2. Hold the ribbon in the flame with the crucible tongs.

3. Record the results.

*******DO NOT LOOK DIRECTLY AT THE RIBBON IN THE FLAME!! *****

COMPLETE THE OBSERVATION SECTION

ACTUAL

rx

Observations

Balance Equation

Type of reaction

1

Mg + HCl à  MgCl2 +  H2

2

  O2  +  H2à H2O

3

  H2O2 MnO2 à O2  +   H2O

4

  Mg  +    O2    → MgO

THEORETICAL DATA:

Reaction 2: The burning splint should pop or make a bigger flame.

Reaction 3: The glowing splint should reignite.

DEMONSTRATION OF ENDOTHERMIC REACTION: DO NOT INCLUDE IN THE WRITE UP!!!

1.       Obtain a 500 ml or 600 ml beaker.

2.       Clean the beaker.

3.       Add 100 ml of vinegar to the beaker.

4.       Record the starting temperature.

5.       Add a half scoop of baking soda to the vinegar.

6.       Once the reaction has stopped, add another half scoop of baking soda.

7.       Repeat steps 5 and 6 until the reaction does not start again.

8.       Record the ending temperature.

9.       Dump the contents down the drain and clean up the lab station.