1, 2 and 3 Student Name: Allvssa waler Instructor Name POST-LAB (EXP #10): 1. In
ID: 1009134 • Letter: 1
Question
1, 2 and 3 Student Name: Allvssa waler Instructor Name POST-LAB (EXP #10): 1. In experiment 9, page 7 showed the atomic spectra of calcium and sodium. These spectra help explain their color results for flame test. What feature(s) would you expect from the atomic spectra of potassium? Explain your reasoning. 2. Shepp Dogg is not feeling himself because he was injured in a mosh pit; as a result, while ing part I of the experiment he dissolves his unknown solid in tap water which was processed through a water softener instead of deionized water. Explain how this might affeet his results. 3· The test for sulfate ion name another substance which would have been equally effective and explain your reasoning. (Hint: the formation of a precipitate proves the presence of sulfate ion). involved the addition of aqucous barium nitrate (Ba(NOsh), CHE-1251 Experiment 1 13
Explanation / Answer
1. Potassium shows a lilac color in the flame test. K has a single valence electron, so we expect a violet (lilac) line in between 400-450 nm in the atomic spectrum of K.
2. Tap water processed through water softner does not eliminate the metal species and the other ions in water. Hence, these ions may interfere in the spectral analysis of the sample and may overestimate the specific metals being analyzed.
3. SO42- can be analyzed by precipitation using a suitable precipitating agent.
Compounds with SO42- are soluble (except with Ba2+, Sr2+, Ca2+, Pb2+, Hg22+, and Hg2+, Ca2+ and Ag+ sulfates are sparingly soluble.)
So we can use any reagent with these ions to preciptate out sulfates.
CaCl2 can be one such reagent.
CaCl2 (aq) + SO42- (aq) -------> CaSO4 (s) + 2Cl- (aq)
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.