Since methylene chloride and water to not mix, by wetting a piece of filter paper with water addition of both layers to the filter funnel results in the aqueous layer passing through the paper and the organic layer remaining in the funnel. This can be poured into another container, dried using sodium sulfate
(a drying agent) and the methylene chloride can be evaporated in the hood leaving behind the pure caffeine. Based on the mass of caffeine, you can now determine the % weight of caffeine in the original tablet. How does this compare with what the packaging states?