CH 204 Lecture Notes - Lecture 1: Ion, Solubility, Formula Unit
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Determining the amount of a species in a sample. Measuring a numeric property of a species: qualitative analysis. Determining the identity of a species in a sample. Qualitative schemes: unknowns 1, 2, 3, and 4. Ag+ or pb2+ and ba2+ or ca2: part a: ag+ or pb2+ Step 8: white precipitate indicates ag: part b: ba2+ or ca2+ But you must confirm it is barium, not calcium. Step 14: another white solid indicates ca2+ General procedure: add the unknown sample to the test tube. Add a specific amount of a reagent to the test tube. Centrifuge isolate the solids from the liquids repeat, repeat, repeat re(cid:272)ord, re(cid:272)ord, re(cid:272)ord follow the qualitative scheme to identify each aqueous cation: each step depends on the solubility of the new compound insoluble yields a precipitate. Soluble yields a color change, gas evolution: write down the number of your unknown.
