During this experiment, we were trying to see whether copper, after a chain of chemical reactions, will revert back to its elemental form.
First, I added nitric acid with copper in a beaker, which turned into a copper nitrate, a blue-green solution. Afterwards, I added sodium hydroxide, and my solution colored to a dark blue solution called copper hydroxide. I heated the solution to evaporate the water and I got a brownish-blackish solid called copper oxide. Once the solid appeared, I poured in sulfuric acid to it and I got copper sulfate, a bluish solution.
The final step I took was to add the element zinc, which turned the solution from blue to clear, with a brown solid in the bottom of the beaker, copper.
During each step, something happened. For instant, for the first step, when I added the acid to the copper, the copper disappeared and the solution turned from the clear acid color to a blue-greenish hue.
In the next step, there was another chemical reaction when I added the sodium hydroxide. The whole solution turned blue when I stirred the mixture. When the time came to evaporate the solution, the liquids disappeared, leaving behind a wet, brownish solid in the middle of the beaker. When the solid was hot, it bubbled and popped until it cooled down. When all the liquids evaporated, I scraped off the solid and put it in a separate beaker. Once I put the sulfuric acid in it, the brown solids (copper oxide) slowly dissolved and turned the acid into blue.
After the acid was blue, I added the metal/grey colored zinc into the solution; the solution bubbled and the zinc turned the solution clear. The zinc disappeared and in its place, copper appeared.
For each step, there was a chemical reaction, except for the part where we evaporated the water/liquefied chemicals. For each step, I was turning the copper into a compound. When an acid was added to the copper, it turned the element into a compound. When a base was added later, it merely replaced the acid with the base.
For this experiment, I can conclude that an element/matter can never be destroyed or created. The copper cycle is evidence for the Law of Conservation of Mass, which states that an element or matter can never be created or destroyed, only changed.