LAB: One Tube Reaction Part 1

Transcription

1 AP Chemistry LAB: One Tube Reaction Part 1 Objective: To monitor and document the chemical changes occurring in a single test tube containing a predetermined mixture of chemicals. Materials: test tube, iron nail, sodium chloride, copper (II) sulfate, distilled water, glass stirring rod, tissue paper, parafilm wax Procedures: 1. Label a test tube to identify your group 2. Fill approx. 1/3 of the test tube with copper (II) sulfate crystals. Gently tap the tube to allow the crystals to settle. 3. Using a glass stirring rod, carefully cover the crystals with a layer of Kimwipe tissue paper. 4. Slowly, and with as little disturbance as possible, add enough distilled water to just cover the paper and blue crystals. 5. Repeat the process for the sodium chloride, filling approx. 1/3 of the test tube. Gently tap the tube to allow the crystals to settle. 6. Push more tissue paper into the test tube on top of the white crystals. 7. Add enough water to cover the tissue paper and white crystals. 8. Obtain an iron nail and expose the surface by rubbing with sand paper. 9. Carefully slide the nail into the test tube. 10. Continue adding water until the nail is completely covered. 11. Cover the test tube with parafilm wax and record your Day 1 observations. 12. Return the test tube to the test tube rack. 13. Continue to monitor and record your observations for the next several days, as indicated in the data table.

2 Data: 1. Complete the NFPA label for the two chemicals used in this lab. Identify any safety precautions that should be taken while working with these materials. Copper (II) Sulfate Sodium Chloride Safety:

3 2. Complete the following data table, recording your observations for the following days: Day # Observations Follow-up questions: (be sure to use complete sentences in your response) 1. Summarize a physical description of the chemicals in their starting state. 2. Summarize the observations observed in the test tube over the five-day period. 3. What evidence suggests that a chemical change is occurring in the test tube? 4. Identify the seven elements that were present in the test tube by their name and chemical symbol. 5. Based on your observations, can you predict any products that were produced during this reaction?

4 One Tube Reaction Part 2 Lab Separation Procedures Objective: to learn separation techniques by separating and recovering the substances used in the one test tube experiment. Materials: 250 ml beaker, Pyrex test tubes, 100 ml graduated cylinder, test tube clamp, test tube holder, scoopula, ring and ring stand, funnel, Bunsen burner, Florence flask, distillation stopper set up, filter paper, watch glass, hot hands. Procedure: 1. You and your partner(s) pour the contents of test tube into one 250 cm 3 (ml) beaker. You may need to add a small amount of water first and break up the solids with a scoop. Place all empty test tubes in the designated recycling area. Add 100 cm 3 of tap water to the beaker and heat it on a wire-gauze/ ring-clamp/ ring-stand set-up. Stir this mixture occasionally. Stop heating in approximately two minutes. Many of the solids in the test tube should dissolve, while insoluble materials will be left at the bottom of the beaker. Record results. 2. Label one sheet of filter paper with your name(s). Set up a filtration apparatus, using a ring clamp to hold the funnel. Filter a few drops of your mixture into a test tube. The solution that passes through the filter paper is called the filtrate. GENTLY heat this test tube until dry IMPORTANT!!(be sure to use proper test tube heating techniques, refer to the video clip on my webpage). Record results. 3. Continue to collect about 50 ml of the filtrate into a Florence flask. Then transfer some of the solid from the beaker to the filter paper with a scoop or spoon. After filtering, open the filter paper and spread it out while still wet, on your watch glass or porcelain dish. Place filter paper and the solids in the oven to dry. The solids in the filter paper are called the residue. Discard everything else from the beaker in the designated waste container. Clean up this beaker today or it will be impossible next time! 4. Add a few boiling stones to the filtrate in the Florence flask. Set up a distillation apparatus using a bent glass tube that has one end fitted into the Florence flask and the other end inserted into a clean, empty test tube. Refer to figure for set up. Use a Bunsen burner to heat the solution in the flask and distill it until a few drops of liquid, called the distillate, are collected in the test tube. Be careful to avoid boiling over the solution into the distillation tube, which would contaminate the final distillate. Allow the test tube to cool for a few minutes before removing

5 from the stopper. 5. Heat the test tube with these few drops of the distillate with a low flame until dry. Again!!! Follow proper test tube heating techniques! Record results. Discard the remaining solution from the Florence flask in the designated waste container. 6. Wash all glassware with soapy water, then rinse with tap water. Return all equipment to their designated areas. ANALYSIS: (data table should be prepared as part of pre-lab) Prepare a data table similar to the pre-lab analysis table with procedure number listed in one column, and observations listed in another column. CONCLUSION: 1. List the separation techniques used in this experiment. Which one was most successful? 2. What is the color of the solution formed in step 1 of the procedure? 3. What is the residue on the filter paper? How is it different from the original substances? 4. What is the chemical in the filtrate recovered in step 2? In step 5? 5. Write complete balanced molecular and net ionic equations for the reactions that occurred in this experiment. 6. Write a final summary paragraph to describe the changes that occurred in the takehome experiment. Include evidence that supports this conclusion.