Warning: Copper compounds are toxic. Do not eat or drink them. Alkalis are corrosive. Wear gloves.
You will need:
Dissolve copper(II) chloride (how to make it is found at http://lanthanumkchemistry.over-blog.com/article-how-to-make-copper-ii-chloride-76079848.html) in water. Divide it into three parts. To one, add sodium bicarbonate. You will form copper(II) bicarbonate, which decomposes instantly, releasing carbon dioxide and converting to copper(II) carbonate.
To the next solution, add sodium carbonate. A blue-green precipitate of copper(II) carbonate will be formed. Basic copper(II) carbonate, where some of the carbonate is replaced with hydroxide, may be formed as well.
To the next solution, add sodium hydroxide. A gelatinaceous blue precipitate of copper(II) hydroxide forms, which decomposes when wet for an extended period of time to black copper(II) oxide. It reacts with carbon dioxide in the air to make basic copper carbonate.
Filter and dry all of these precipitates. Heat them in a test tube or an aluminium foil boat (if you are cheap). They will turn black and create copper(II) oxide, releasing water vapor, carbon dioxide, or both.
The picture on the left is copper(II) carbonate. The picture on the right is copper(II) oxide.