Lab 5 - Qualitative Analysis

Sol ubi l i t y i n hot wat er 5 add 10 drops of

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Unformatted text preview: or confirmatory tests. Sol ubi l i t y i n Hot Wat er 5 Add 10 drops of deionized water to the precipitate that formed in step 1 and was washed in step 4. Place the tube in a boiling water bath for several minutes, stirring frequently with a clean stirring rod. Record your observations in Data Table C1 (color change?, redissolve?, etc.) 6 Centrifuge your sample. Decant the supernatant liquid into a clean test tube and perform a confirmatory test. Confirmatory Test: Add 5 drops of 0.2 M KI to the test tube. Record your observations in Data Table C2. The contents of this test tube may be discarded into the waste. 7 Wash the solid as you did in step 5 of Part B. Discard the washing liquid into the waste. Sol ubi l i t y i n Ammoni a 8 Add 10 drops of 3 M NH3 to the solids that did not dissolve in hot water and were washed in step 7. Record your observations in Data Table C1. 9 If a solid remains, centrifuge your sample. Decant the supernatant liquid into a clean test tube and perform a confirmatory test. Confirmatory Test: Add 5 drops of 0.2 M KI to the test tube. Record your observations in Data Table C2. The contents of this test tube may be discarded into the waste. Part D: Separating and Identifying Components of an Unknown Mixture. www.webassig n.net/ebooks/wsug encheml1/lab_5/manual.html 5/6 4/15/13 Lab 5 - Qualitative Analysis 1 Place 15 drops of an unknown mixture in a clean test tube. Record the unknown code in the heading of Data Table D1. The unknown contains some combination of Ag1+, Pb2+ and Hg22+ ions. 2 Follow steps 1 - 9 from Part C on the unknown sample while your partner performs these steps on the known mixture. At each step, compare the unknown results to the known results to identify the ions in the unknown mixture. At each step, remember to: • Record your observations in Data Tables D1 and D2. • Save all supernatant solutions for confirmatory tests. • Wash solid samples before going on to avoid contamination with soluble ions. 3 Turn off your hot plate. When cooled, pour your wat...
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This document was uploaded on 01/22/2014.

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