The Purity and Purification of Solids -- Recrystallization

The Purity and Purification of Solids -- Recrystallization

Abstract: In this experiment, impure adipic acid is purified through recrystallization. The impure adipic acid is dissolve in a solvent. After filtered the hot solution and ran through a vacuum filter to separate any moisture. The dry crystals are than weight for percent recovery and the melting point range is taken to test the purity. The different between part A and part B was the addition of charcoal in the initial step to remove color impurities in part B. In part A without charcoal, the initial impure weight was 1.005g and after filtration was 0.369 with 36.7% recovery. The melting point range for this was 152.8-153.1 Celsius. Part B with charcoal, the initial impure weight was 1.003g and after filtration was 0.357g with 35.5% recovery. The melting point range for this was 154-157.1 Celsius.

Introduction:

Recrystallization is a method that is used to purify solids. Recrystallization depends on differences in solubility at different temperature. Solubility is one of the physical properties of a substance and substance to dissolve in a liquid. To have a god test, two criteria must be met. A high degree of purity is achieved after the purification and there must be a maximum recovery of the sample. This technique of purification is only effective when there is a smaller amount of impurity in one substantial component. This experiment is to determine the purity and purification of the impure adipic acid.

Experimental:

Part A:

1. Add 1.0g of impure adipic acid and about 6mL water then heat the mixture and stirring until all the crystal dissolved.

2. Filter the hot solution through fluted paper into a second Erlemeyer flask and re-heat until all the crystal dissolve.

3. Set