To remove the impurity, the fluorene had to be recrystallized and purified. In a secondary step, 15 ml of ethanol was heated until the solvent boiled. Ethanol is the ideal solvent for crystallizing fluorene because it is polar. Although fluorene is nonpolar, fluorene is neither too soluble nor insoluble in ethanol. The decision to select this solvent also came from previous experiments. Initially, methanol would have been a good solvent for fluorene, but methanol evaporates very quickly. A larger amount of methanol would have been needed to dissolve the impure fluorene, but a small amount of ethanol is only needed to completely dissolve the impure fluorene. Once the ethanol solvent was boiling, a small amount was added to the flask, just enough to cover the impure fluorene solids. This flask was then heated on a hot plate and additional hot ethanol was added continuously until the fluorene was completely dissolved (10). As soon as the solid dissolved, the flask was stoppered and placed in an ice water bath (11). Crystallization occurred almost