I have to do a chem lab where there is water with lead and copper nitrates. Today we put in potassium iodide to get rid of the lead nitrates, but how do we get rid of the copper nitrates. we have to get the water to clear (its green now) and a pH of 7 (its way below that, very acidic) so any ideas? thanks so much!
2007-06-28 10:38:29 · 6 answers · asked by ♥...........♥ 5 in Science & Mathematics ➔ Chemistry
To get rid of the copper nitrates you would add a solution of sodium hydroxide. This will raise the pH and as it does so it will precipitate out insoluble Copper hydroxide Cu(OH)2. Once you have precipitated it out, filter the solution and you will end up with a clear solution.
2007-06-28 11:21:11 · answer #1 · answered by scott k 4 · 0⤊ 1⤋
It's quite simple. Basically you put the mix of water and copper nitrates into an evaporating dish. Then put the corresponding glass cover over the dish. Then have that dish sit under a flame, hovering about 6 inches above (use a post that holds the dish with a ring and wire surface...forgot the name). I forgot all of the special names for the lab equipment, but this is the proper way to perform the task. Let me continue...then after you begin to see some evaporated water sticking to the glass cover, slightly slide the glass cover to the side, providing a minor slit for the excess evaporation to escape. Then, when all of the water is evaporated (there will be only evaporated water droplets sticking to the glass, none at the bottom of the dish mixed in; that is how you will know.), you stop the heating and allow a few minutes for cooling. After the cooling has finished, remove the dish from the area and all of the evaporated water droplets on the glass will be your clear, fresh water; the copper nitrates will remain at the bottom of the dish.
Hope this helps!
2007-06-28 17:54:13 · answer #2 · answered by βread⊆ℜumbs™ 5 · 1⤊ 0⤋
Are you trying to get the copper to precipitate out of solution?
If so, try adding potassium chloride. The chloride will combine with copper and precipitate out. K+ has a neutral pH (7), as does Cl-, since they are the weak conjugates of KOH and HCl. I- is also neutral, so the pH should become 7.
The green color is from the copper so if it precipitates out the color should become clear.
2007-06-28 17:50:08 · answer #3 · answered by Anonymous · 0⤊ 0⤋
What you did was: Pb2+ + 2NO3- + 2K + 2I- ===> PbI2(s) + 2K+ + 2NO3-
Cu2+ + 2NO3- + 2K+ + 2OH- ===> Cu(OH)2 + 2K+ + 2NO3-
If you do it exactly right, you will come out with a solution of KNO3(aq) with a pH of 7, but what are you going to do with all that KNO3?
2007-06-28 17:59:36 · answer #4 · answered by steve_geo1 7 · 0⤊ 0⤋
i really hope one of these helps
http://antoine.frostburg.edu/chem/senese/101/tutorials/
http://science.csustan.edu/tutorial/
http://www.biology.arizona.edu/biochemistry/tutorials/chemistry/page3.html
http://www.science.uwaterloo.ca/~cchieh/cact/applychem/waterchem.html
2007-06-28 17:45:57 · answer #5 · answered by Anonymous · 0⤊ 0⤋
dont recall
2007-06-28 17:59:11 · answer #6 · answered by tiara_cooks 1 · 0⤊ 3⤋