Weigh 3 mmole of imidazole and add it to the Erlenmeyer flask containing the solution of copper nitrate. Swirl the flask to dissolve the imidazole. Record any observations in detail. Place the flask in an ice bath for 10-15 minutes to allow the product to crystallize. Using a flat-ended spatula or a stirring rod, dislodge the crystals from the sides and bottom of the flask, then let stand for another 5 minutes.
Suction filter the mixture to isolate the solid, and suction it dry.
Transfer the product to a small Erlenmeyer flask or beaker and add 1-2 mL of distilled water. Gently heat the mixture to dissolve all or most of the solid, then filter the hot solution through a Kimwipe-plugged Pasteur pipet into another small Erlenmeyer. Place the filtrate in an ice bath. When crystallization is complete, collect the product by suction filtration. Wash it twice with 2-mL portions of acetone, suction it completely dry, and determine the mass of product obtained.