Objective, background, and how this lab works
Objective: Observe how eight common household chemicals behave in order to determine their physical and chemical properties, then use your results to identify an unknown powder.
Five reagents help identify the powders based on solubility, reactivity, or acid/base nature:
- Distilled water: three powders are insoluble and five are soluble. Look for a decrease in the amount of solid.
- Iodine solution: turns blue in the presence of starch; stays brown if no starch is present.
- Vinegar (acetic acid): reacts with carbonates to make bubbles of carbon dioxide gas.
- Litmus paper: red litmus turns blue in a base; blue litmus turns red in an acid. Test a solution, not the dry powder.
- 70% isopropyl alcohol: compares how well the neutral powders dissolve in alcohol.
Steps: (1) Pick a reagent, then click a test tube on the bench. (2) Record what you see in the observation log. (3) Sort the tubes into the flowchart in Parts A and B. (4) Test the unknown. (5) Answer the conclusion questions and write your claim, evidence, and reasoning. You need at least 80% on every section to earn your certificate, and you can retry any section.
Simulation note: in the real lab, water and vinegar tests use separate fresh tubes. Here, each tube holds a fresh sample, so you can test it as many times as you like. Add water to a tube before using iodine or litmus on it.
Lab bench
Reagents (choose one, then click a tube)
Observation log
| Tube | Test | Observation |
|---|
Part A: Insoluble compounds
Run the water, iodine, and vinegar tests, then place each tube number in the flowchart boxes it belongs in. A powder belongs in every box that describes it. Select a number, then click a box. Click a number inside a box to remove it.
Part B: Soluble compounds
Use litmus paper to sort the water-soluble powders as basic, acidic, or neutral. Then test the basic ones with vinegar and the neutral ones with alcohol (one dissolves more than the other).
Part C: Identify the unknown
Tube U on the bench holds one of the eight powders. Run the same tests on it, report what you observed, and name the compound.
Conclusions
Claim, Evidence, Reasoning
Question: What is the identity of the unknown powder in tube U?
Claim: a one-sentence answer. Evidence: the specific observations from your tests. Reasoning: explain how the physical and chemical properties you observed connect the evidence to your claim.
Claim
Evidence
Reasoning
This check looks for key ideas in your writing. Your teacher may also review your response.
Certificate of Completion
This certifies that
completed the Observation of Properties lab simulation
and scored at least 80% on every section.