will not dissolve in water at room temperature but on at an elevated temperature. This is due to that fact that they are similar enough with regards to strong intermolecular forces. After water was added at room temperature, acetanilide was not soluble. Once the mixture of water and acetanilide was heated, acetanilide easily dissolved into the water. Finally, once the mixture cooled down, the formation of crystals was present. It is a good recrystallization solvent since acetanilide does not dissolve at all temperatures and only at close to boiling temperatures. Also, the appearance of crystals once the mixture was cooled back indicates acetanilide is a good recrystallization solvent. According to the CRC Handbook of Chemistry, one gram of acetanilide will dissolve in 20 mL of boiling water. For this experiment, to dissolve 5 g of acetanilide in water requires 100 mL of water. For this experiment only 50 mL of water was used to allow for the recrystallization of acetanilide. For Part 2, provide the following data and answer the post-lab questions. Mass of Crude Acetanilide: ________5.065 g _______ 1
Mass of "wet" recrystallized acetanilide: ________3.804 g_______ Mass of dry recrystallized acetanilide: ________3.296 g _______ Percent recovery: _______ _65 %________ Mp of crude acetanilide: ________N/A ___________ Mp of dried recrystallized acetanilide: ___112.9 C – 115.3 C ____ Mp of authentic acetanilide: ___114.7 C – 117.3 C ____ Literature mp of acetanilide: _____113 C – 115 C _____ Literature Reference: __www.sigmaaldrich.com_ (1) List at least 5 reasons that the percent yield is less than 100 percent.
- Spring '07