From: NFetter@aol.com
Date: Sat Nov 18 2000 - 22:56:17 PST
From: NFetter@aol.com Message-ID: <bb.8fa1e40.2748d391@aol.com> Date: Sun, 19 Nov 2000 01:56:17 EST Subject: Re: pinhole Cupric Sulfate
Hi Dan,
I can think of three lab possibilities with copper sulfate
1. If you have the blue copper sulfate pentahydrate, you can heat a few grams
in a test tube with a Bunsen burner. You can see the water of hydration
condense on the upper part of the tube and the blue copper sulfate turns
white. After the tube has cooled add a little water and see the blue color
return and touch the tube CAUTIOUSLY.
2. Dissolve some copper sulfate in water to make a blue solution. Have the
students scrape the copper layer off a post 1982 penny and drop the penny in
the solution. A black layer will form on the zinc interior of the penny. This
layer is finely divided copper metal. If you leave the penny in the copper
sulfate long enough, the zinc part of the penny will dissolve.
3. Using the same copper sulfate solution, place two copper strips in it and
connect the strips to a low voltage direct current source. Eventually you
will see a copper "tree" on one of the strips. These growths are called
denerites. I will let you figure out on which strip the dendrites will appear
(+ or-).
Neil Fetter
This archive was generated by hypermail 2b29 : Tue Oct 16 2001 - 12:22:01 PDT