Copper(II) chloride, also known as cupric chloride, is an ionic compuond with the formula CuCl2. Anhydrous, it is a dull brown hygroscopic solid. As it absorbs moisture from the air, it changes to a light green color. It burns with a bright green flame.
Place some chunks of copper in a beaker. I used wire scraps and bits of pipe. Make sure they are large enough to be easily seperated.
Add enough hydrochloric acid to cover the copper. Watch how much you use--we want the acid to be the limiting reagent. The solution will quickly turn to a light yellow-green color. Let it sit overnight.
Eventually, the mixture will take on a darker yellow-orange color. You may see some dark precipitation. Decant the liquid into another beaker.
Place it on a hot plate, and simmer until it has fully evaporated. Remove it from the hot plate.
Let it sit until it's cool enough to handle. The color will partially change to a blue-green.
Using a scoopula, scrape and crush it into a powder. It should now be a brown color.
Let it sit for an hour or so while it absorbs moisture. Check out that hygroscopic action! It's now light green.