Michael Jansen sent in this photo of a Florence flask at the end of the Remsen Demonstration. After the reaction, 100 mL of 50% aqueous ammonia solution was slowly poured on top of the Cu(NO3)2(aq). The dark blue solution is [Cu(NH3)4]2+;the pale blue is [Cu(H2O)6]2+; the thin white band in between is Cu(OH)2(s). The demonstration was taken from www.chemmybear.com/demo.htm.
