Solving a Problem in the Chemistry Lab

Although I love science, I encountered more problems in this subject than any other. Recently, I was assigned a lab. The purpose was to let Copper Sulfate react with Aluminum and obtain Copper. Before the experiment, I set up the stoichiometric equation carefully, predicting the production of Copper using my assigned mass of Copper Sulfate. Additionally, I intentionally made Copper Sulfate an excess in my equation, since it would be dissolved in water and I would only have to collect Copper at the end, to get the highest percent yield. Unfortunately, I did not obtain what I wanted. I performed multiple trials carefully, but I was unable to filter the mass of Copper I expected. I noticed that during all trials, the reaction occurred very slowly, and produced gray precipitate. All samples from my class were similar, except one, where the precipitate was produced very quickly and was red instead of gray. I believed that the sample may have been more similar to the chemical equation; therefore I tried to help my friend to recreate the condition, but we were unable to do that. My friend suggested that there may have been an oxidation reaction before the experiment. Keeping that in mind, I checked the information of each reactants and products on online resources. Not only did that help me realize the Aluminum was oxidized, it helped me understood that the product was the gray Copper (II) Oxide instead of the red Copper (I) Oxide. This was one of the problems that I was able to solve by careful observation and checking additional