Ch100: Fundamentals for Chemistry 1Instructor: Tony ZableLaboratory #7: Kitchen AnalysisI. Purpose· Apply observations to determine the identity of a substance· Observe the reactions of 4 different common kitchen substances:1. starch2. baking soda3. baking powder4. salt· Analyze a mixture containing 2 of the above substances and predict their identities.II. TheoryThere are 4 bottles on a cart labeled A, B, C, and D. Using the information below, determine what is in each bottle.1. Starch will produce a dark violet solution with the addition of iodine solution.2. Baking soda (sodium bicarbonate, NaHCO3) will effervesce when vinegar (acetic acid, HC2H3O2) is added to it.3. Baking powder (sodium bicarbonate plus a solid acid and starch) will bubble when water is added to it; but baking soda will only effervesce when vinegar is added to it.4. Salt (sodium chloride, NaCl) will produce a white cloudy solution when nitric acid andsilver nitrate is addedBefore you get started:Obtain samples of starch, baking soda, baking powder, and salt. Using test reagents, iodine, silver nitrate, water, and vinegar, verify the above results and record your observations in Table 1 below.Table 1. Verification of “Expected” ObservationsIodine Vinegar Water Silver NitrateStarchBaking SodaBaking PowderSalt1Ch100: Fundamentals for Chemistry 2Instructor: Tony ZableIII. Procedure:Part 1: Identification of unknown substances1. Use a spot plate for identification of the substances: A, B, C, and D. 2. Place a small amount of each substance in a row. 3. To the first column add iodine solution and record the results in Table 2.4. To the second column add vinegar. Record the results.5. To the third column add water. Record the results.6. To the fourth column add nitric acid and then silver nitrate. Record the results.7. With the above information and your results, identify the substances A-D.Table 2. Experimental ObservationsIodine Vinegar Water Silver NitrateABCDPart 2: AnalysisBased on the information in the Theory section and your observations, predict the identity of each unknown substance:A ___________________B ___________________C ___________________D ___________________2Ch100: Fundamentals for Chemistry 3Instructor: Tony ZablePart 3: Observations of an unknown mixtureFollow the same procedure as above with the unknown mixture and record your results in the table.UnknownCodeIodine Vinegar Water Silver NitratePart 4: The Final AnalysisUsing the results from Table 2, determine the identity of the two substances in the unknown mixture.__________________________ and __________________________3Ch100: Fundamentals for Chemistry 4Instructor: Tony ZableSample Iodine Vinegar Water
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