Separation of Mixtures Lab & Rubric

In this lab students devise their own unique strategies to separate a mixture of water, methanol, sand, salt, iron and copper. Each component of the mixture should be analyzed quantitatively for its mass, percent composition as well as percent error as compared to the actual value. (note: the teacher or instructor needs to create the stock samples and must know the actual value of each component in the mixture). I would recommend using between 40 - 130 grams of water, 3 - 8 grams methanol, 2-4 grams salt, 3 - 10 grams of sand, 8 - 20 grams of copper and 8 - 20 grams of iron in a 250 ml stoppered flask). This activity/lab can really challenge the students thinking and it may require multiple attempts over several days. It also challenges students to explain their percent error. Rubric or scoring guide is attached. For a less complex version of the lab you can exclude alcohol and water and just combine the other components in a ziplock.