CHEM 101DL Lecture Notes - Lecture 4: Metal, Flowchart, Ion

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ivorybat284

4 Apr 2016

School

Duke University

Department

Chemistry

Course

CHEM 101DL

Professor

Christopher Roy, Mac Phail

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Document Summary

With the above flowchart as our guide, we separated and identified compounds to figure out which of the four possible cations were present in our unknown. The process to identify compounds consisted of us adding known solutions to our unknown. If a precipitate formed, we were able to identify a cation present in the unknown. If the known solution was added and no precipitate formed, we were able to identify which cations were not present in the solution, because a precipitate would have formed if they were. The separation came into play when a precipitate formed and we removed the unprecipitated unknown solution and put it in a new tube to continue to add known solutions to. We began by adding hcl to our unknown. We then added na2so4 and a precipitate formed, showing us that ba2. We transferred all of the solution that did not precipitate to a new tube and added nh4oh.

Related Questions

You first treated your unknown solution with and and a yellow precipitate formed. The liquid remaining atop this precipitate was removed after centrifugation, and to it was added . No new precipitate formed. Next, a solution of was added to the unknown solution which had been treated in the fashion described. A white precipitate formed. This mixture was centrifuged and separated, and the clear solution was then treated with . No precipitate formed. Which metal ions were present in your unknown? Which metal ions were absent?