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Unknown Scheme 2 - Sarah Swaney Chemistry Lab Scheme...

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Sarah Swaney Chemistry Lab Scheme Unknown 9A/9B I. Possibilities A. Cations: Na + , K + , NH 4 + , Ca 2+ , Mg(H 2 O) 6 2+ , Al(H 2 O) 6 3+ , Zn(H 2 O) 6 2+ , Cu(H 2 O) 6 2+ , Ag(H 2 O) 2 + B. Anions: Cl - , NO 3 - , SO 4 2- , HSO 4 - , OH - , O 2- , CO 3 2- , HCO 3 - , S 2- , HS - C. 2A and 2B are mixtures! II. Pre-Lab Procedure A. Make neutral H 2 O from deionized water. B. Clean instruments. C. Get supplies: litmus paper, pH paper, indicators, reagents… D. Unknown Card E. Set Timer (60/60) 120 minutes total! F. Save half of original sample ICE III. Original Sample Description : phase, color, odor, shape IV. Test on Solid Sample A. Flame Test 1. Yellow/Orange – Na + (maybe K + or NH 4 + ) 2. Purple – K + 3. Red – Ca 2+ 4. Green – Cu(H 2 O) 6 2+ B. No Color – NH 4 + , Mg(H 2 O) 6 2+ , Al(H 2 O) 6 3+ , Zn(H 2 O) 6 2+ , Ag(H 2 O) 2 + 1. C. NH 4 + Test 1. Add NaOH (aq) 2. Hover wet red litmus paper over solution. (Blue = NH 4 + positive) 3. Heat solid in crucible (Gray fumes = NH 4 + positive) V. Test on Aqueous Sample Add neutral H 2 O to solid (solid + 10-15mL H 2 O) then test with indicators and pH paper 1. HSO 4 - = pH 2 2. NH 4 + = pH 5-6 3. Cl - NO 3 - , SO 4 2- , K + , Na + = pH 7 4. OH - = pH 13 (No HSO 4 - , NH 4 + ) VI. Specific Ion Tests (1/2 sample + neutral H 2 O into vials) A. K + AND NH 4 +
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