Solubility Tests and Recrystallization Lab Write Up
Five compounds were added to four different solvents. The solvents were all clear liquids. The compounds were Anthracene, a thin white powder, Benzoic Acid, a crystalline white solid substance, Phthalic Acid, a white solid substance, Resorcinol, solid, white “pebbles” and Sodium Aphthionate, a fine pinkish coloured “sand” like material. Table 1 describes how soluble each compound was in the different solutes. Approximately 100 mg of each compound was added to approximately 3 mL of solvent. Many solutes showed no solubility within a given solvent and the two substances would remain in distinctly different states (solid and liquid). The solutes that did demonstrate solubility makes sense given the “like dissolves like” principle. Polar solutes like water and ethanol dissolved in more polar solutes such phthalic acid, resorcinol and sodium napthionate. The more nonpolar solvents such as ligroin and toluene were better at dissolving very nonpolar solutes such as anthracene or benzoic acid.
One gram of crude Salicylic Acid (weighed out to precisely 0.96 grams) and 20 mL of water were combined in a 150 mL beaker, heated to boiling. 19 more mL of water was added until the sample was able to dissolve at the boiling point (bringing it to 39 mL total). Around 0.02 g of Charcoal was added to the sample. This was boiled again and the sample was placed in an ice bath where it crystalized further. After the sides of the beaker were “scratched” with a spatula, crystallization was increased. The Crystallization resulted in colourless needle shaped crystals.
Table 1: Solubility of Five Solutes In Four Solvent s
SOLUTES | Ligroin | Toluene | Ethanol | Water |
Anthracene | Hot: NSCold: MSNo Crystal Seen | Hot: NSCold: MSNo Crystal Seen | Hot: NSCold: NS | Hot: NSCold: NS |
Benzoic Acid | Hot: NSCold: NS | Hot: FSCold: NSAmorphous Crystals | Hot: FSCold: MSAmorphous...