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How to write a lab report

How to write a lab report. Percent Water in a Hydrate Lab. Purpose (look in experiment overview). The purpose of this experiment is to analyze the percent water in an unknown hydrate and identify the hydrate from a list of possible unknowns. Materials (from lab report). Balance Bunsen burner

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How to write a lab report

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  1. How to write a lab report Percent Water in a Hydrate Lab

  2. Purpose (look in experiment overview) • The purpose of this experiment is to analyze the percent water in an unknown hydrate and identify the hydrate from a list of possible unknowns.

  3. Materials (from lab report) • Balance • Bunsen burner • Clamp • Unknown hydrate, 2 g • Striker • Scoopula • Ring stand • Test tube • Test tube clamp • Heat resistant pad

  4. Safety • Goggles must be worn as well as tying back long hair. Avoid contact and ingestion of chemicals. Wear a lab apron to protect clothes.

  5. Procedure • (1) Observe and record color and appearance of unknown hydrate in the data table. Record the label code.

  6. (2) Set up the equipment as shown in the diagram.

  7. (3) Measure and record the mass of a clean, dry test tube. • (4) Transfer about 2 g of the assigned unknown hydrate to the test tube. Measure and record the combined mass of the test tube + hydrate.

  8. (5) Slightly spread out the hydrate in the test tube while holding at an angle. Place the test tube in the clamp. Using the Bunsen burner, heat the hydrate by sweeping the flame on the bottom and sides of the tube. • (6) As water condenses near the top of the tube, sweep the flame over the mouth of the test tube to evaporate the water.

  9. (7) Remove the flame when no more water is observed on the test tube. Allow the tube to cool for 8-10 minutes. • (8) Once the tube is cooled, measure the combined mass and record in the data table

  10. (9) Reheat the test tube an additional 2-3 minutes, allow to cool, and mass again. Record the mass. • (10) If the mass has changed, repeat step #9 until there is no change in mass. • (11) Observe and record the color and appearance of the anhydrous residue.

  11. Data • Make data tables like the ones in your lab report. DO NOT cut them out and paste them in. • This lab has a table in the post lab questions. I don’t think it’s necessary to recopy it. Solve it on the handout and use the information in your Analysis and Conclusion.

  12. Analysis and Conclusion (Post lab) • Do not write the questions and the answers! • It must be written in paragraph form like a report.

  13. Question 1 reworked • In this investigation, the original mass of our unknown hydrate was _______ g. As we heated our sample, ______ g of water was lost. Using this information, the percent water in our hydrate was ____ %.

  14. Question 2 and 3 reworked • Using our calculated percent water, we compared this value against a table of theoretical yields for hydrates and determined our hydrate was _______________.

  15. Question 4 and 5 reworked • Based on this information, our percent error was _________. Other groups that had the same unknown in this investigation had (similar, different) results than our investigation. It can be determined that the results (were/were not) precise.

  16. Note for 4 and 5 • If it is determined not to be precise, describe sources of human error (wasn’t heated long enough, wasn’t cooled long enough, spilled sample, etc.).

  17. Question 6 and 7 reworked • It was observed that our sample (did/did not) change color and appearance through the application of heat. Our hydrate can be described as a pure substance because ______________________________ • _____________________________ • (look in the background section!)

  18. 6 and 7 continued • Because our hydrate is a pure substance, the conversion to an anhydrous salt is a chemical change.

  19. This experiment demonstrated _____ • ______________________________ • It could have been improved by _____ • _______________________________ • (Do NOT write NOTHING! Do not write something facetious! Every time we do a lab it can be done better. You are not perfect and to claim so would come off as arrogant.)

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