We did a lab where we had to remove soap from water... We tested with different substances. We had to put plaster of paris, borax, epsom salt, and sugar into 4 seperate test tubes filled with a soapy water mixture. By shaking the test tube, soap suds would arise, and we were to measure them. Then we compared with a plain test tube filled with just soapy water. The plaster of paris removed the most soap from the water!
Now we have questions to answer and i am really confused with this one:
What criteria did you use to determine if your experiment worked?
Does anybody have a clue? PLEASE? =[
2007-09-15 11:40:24 · 2 answers · asked by addisyn 2 in Science & Mathematics ➔ Chemistry
Soap is basically the salt of a long chain fttay acid and using paster of paris you are doing an ion exchange experiment.
Ususally the ion the is attached to the fatty acid portion in soap is is either Potassium (Lye soap) or sodium.
Plaster of paris is escentially CaSO4 suspended in water. The Ca+2 exchanges with the K+/and or/Na+ ion to for the Ca-Soap which since it is not less water miscible settles out of solution.
How do you determine whether the experiment worked? -Wheh
well, if you do a flame test on the supernatant liquid you should see Na+ an/ot K+ ion in this solution.
As far at the solid - hmmmm- To this add a very conentrated solution of Na2CO3
if you are lucky you will get the soap back and CaCO3 as a ppt.
2007-09-15 12:02:00 · answer #1 · answered by Dr Dave P 7 · 0⤊ 0⤋
Whether the soap suds subsided, failed to form. Plaster of Paris is CaSO4. Ca should form an insoluble precipitate of the soap, and thus prevent soap suds. But Epsom salts, MgSO4, should do the same thing. Borax is sodium tetraborate, and should do nothing; likewise sugar.
2007-09-15 11:52:01 · answer #2 · answered by steve_geo1 7 · 0⤊ 0⤋