Copper Coin Experiment

In Science we did an experience using a 10 cent coin. The experiment involved changing the colour of the coin, which it was made out of copper. First we set up a bunsen burner alone with a heating mat underneath and a tripod plus gauze mat on top. In a beaker we added 50mL of 2molL+ NaOH. After that we heated it up over the bunsen burner until it was nearly boiling. Once we did that, we added a spatula of zinc powder and heated it up again for three minutes, along with putting the coin in it - stirring as it heated. We then took the coin out with tongs and rinsed it under water to get rid of any remaining chunks of zinc. At this stage the coin had changed colour from a bronze to a silver. Lastly we put the coin - holding it with tongs - in the flame. From that, the coin had changed colour from the silver to a gold colour. This had made brass, which was an alloy of copper + zinc. An alloy is a metal made up of more than just one metal.