TYPES OF CHEMICAL REACTIONS LAB - Mr. Shanks' Class



Introduction

Matter can undergo both physical and chemical changes. Chemical changes result in the formation of new materials. Observable signs of chemical reaction include the release of a gas, a change in color, the formation of a solid, and the production of heat and light.

Chemical reactions can be classified in many ways. One classification system involves five general types of reactions: synthesis, decomposition, single displacement, double displacement, and combustion. In this lab, you will perform several reactions and classify them as one or more of the five general types.

Materials

• 2 pairs of goggles

• 2 pairs of gloves

• 2 safety aprons

• NaSO4 (aq)

• Ba(NO3)2 (aq)

• Bunsen burner

• flint lighter

• Mg(s) tailings

• HCl (aq)

• Cu (s) shred

• 2 scupulas

• 4 wooden splints

• test tube clamp

• 3 plastic pippettes

Safety

• When heating a test tube, aim the mouth of a test tube AWAY from yourself and others.

• Wear goggle and gloves, as directed by your instructor.

• Hydrochloric acid can cause burns to the skin and damage the eyes.

Procedure

Reaction A

1. Add a squirt (~1 mL) of sodium sulphate solution, Na2SO4, to a clean test tube. Next, add a squirt of Barium Nitrate solution, Ba(NO3)2, to the same test tube. Record your observations.

Reaction B

2. Stand a clean test tube in the test tube rack and add 1 to 2 squirts of hydrochloric acid. CAUTION: HCl can cause burns! Carefully drop a scupula of magnesium tailings into test tube.

3. While the reaction is still occurring, use a test tube clamp to hold an empty test tube over the top of the first test tube for ~30 seconds. Meanwhile, another group member should light the burner and use it to ignite a wood splint. At the end of 30 seconds, hold the inverted test tube (keeping it inverted) while the other group member places the burning wood splint into the mouth of the inverted test tube to test for the presence of hydrogen gas (a loud “whoop!” should be heard).

4. Record your observations, including the results of the hydrogen test. KEEP THE BURNER LIT FOR REACTION C.

Reaction C

5. Place two scupula tips full of copper (II) carbonate, CuCO3, in a clean test tube. Note the appearance of the sample in your observations.

6. Using a test tube clamp, heat the CuCO3 strongly in the burner flame for 2-3 minutes. AIM THE MOUTH OF THE TEST TUBE AWAY FROM YOURSELF AND OTHERS. After heating, another group member should ignite a wood splint and quickly place the burning splint into the test tube to test for the presence of CO2 gas.

7. Record your observations, including the results of the CO2 test. KEEP THE BURNER LIT FOR REACTION D.

Reaction D

8. Place a watch glass next to the burner. Examine a piece of copper shred and record your observations. Using crucible tongs, hold a pinch of the shred in the burner flame until the copper starts to burn. Make not of colour changes you see. Hold the burning copper directly over the watch glass. When the shred stops burning, place the remains on the watch glass. Examine this product thoroughly and record your observations. Turn off the burner.

9. Clean your test tubes and lab station. Put liquids in the appropriate container provided by your instructor. Wrap solids in a paper towel before discarding them in the trashcan.

Observations

Record the appearance of the reactants before and the products after each reaction takes place.

|reaction |before reaction |during/after reaction |

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Analysis

The following equations represent each actual reaction that occurred for Reactions A, B, C and D. First BALANCE each equation. Then CLASSIFY the reaction as one (or more) of the five general types of reactions – synthesis, decomposition, single displacement, double displacement, or combustion.

____ NaSO4 (aq) + ____ Ba(NO3)2(aq) ( ____ BaSO4 (s) + ____ ______(aq) ___________________

A. ____ Mg(s) + ____ HCl(aq) ( ____ _________(aq) + ____ ______(g) ___________________

B. ____ CuCO3(s) ( ____ ______(s) + ____ ______(g) ___________________

C. ____ Cu(s) + ____ O2(g) ( ____ ______(s) ___________________

Conclusions

Answer the following questions based on the results of your lab:

• What signs did you observe that indicated a chemical reaction was taking place? Be specific.

• A combustion reaction was taking place each time you used the Bunsen burner to burn methane gas (CH4). Write a balanced chemical equation for the combustion of methane.

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