Qualitative Analysis (Week 1) Post-Lab

Qualitative Analysis (Week 1) Post-Lab - Q# Question Text...

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Q# Question Text 5) Scoring Scheme: 3-3-2-1 Question 1a) An unknown solution could contain any or all of the following cations: K + , Ca 2+ , Cr 3+ , Mn 2+ , Fe 3+ , Co 2+ , Zn 2+ . A 1 mL portion of the unknown is treated with 2 mL of 6 M NaOH, added a few drops at a time with shaking. Immediately thereafter, 10 drops of 3% hydrogen peroxide are added dropwise with shaking, and the test tube is then heated for a few minutes in a water bath until bubbling ceases. The resulting conglomerate is then centrifuged and the supernatant liquid is decanted off and saved. (Although you have not demonstrated these facts for yourself, Ca 2+ will be precipitated as the hydroxide at this stage and K + will remain in the decanted liquid.) At this stage of the experiment which elements could be found in the DECANTED LIQUID? Select all that apply. Your Answer: a. K You Scored 3 points out of 3 Possible Your Answer: c. Cr No Points Possible Your Answer: g. Zn No Points Possible 6) Scoring Scheme: 3-3-2-1 Question 1b) An unknown solution could contain any or all of the following cations: K + , Ca 2+ , Cr 3+ , Mn 2+ , Fe 3+ , Co 2+ , Zn 2+ . A 1 mL portion of the unknown is treated with 2 mL of 6 M NaOH, added a few drops at a time with shaking. Immediately thereafter, 10 drops of 3% hydrogen peroxide are added dropwise with shaking, and the test tube is then heated for a few minutes in a water bath until bubbling ceases. The resulting conglomerate is then centrifuged and the supernatant liquid is decanted off and saved. (Although you have not demonstrated these facts for yourself, Ca 2+ will be precipitated as the hydroxide at this stage and K + will remain in the decanted liquid.) At this stage of the experiment which elements could be found in the PRECIPITATE? Select all that apply. Your Answer:
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This note was uploaded on 03/08/2011 for the course CHE 2C taught by Professor Enderle during the Summer '10 term at American High.

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Qualitative Analysis (Week 1) Post-Lab - Q# Question Text...

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