Chem 31.1 Experiment 2 Recrystallization and Melting Point Determination of Benzoic Acid
RECRYSTALLIZATION AND MELTING POINT DETERMINATION OF BENZOIC ACID
ANSWERS TO QUESTIONS 1. How does the use of fluted filter paper hasten filtration? Why is it advisable to place a small piece of wire between the funnel and the mouth of the flask during hot filtration?
Fluted filter paper is effective in preventing crystal formation in the filter paper. It is also often used in filtering hot saturated solution used during crystallization. One major advantage of a fluted filter is that it increases the speed of filtration. The crisscrossing of the folds help alleviate the pressure to make the flow of filtration faster. The surface are of the filter paper also increases thus more solvent seeps and enter the flask. Fluted filter paper is also used in filtration that needs the solute instead of the solvent. In order to get the recrystallized benzoic acid, fluted filter paper was needed to be used.
The small piece of wire attached between the funnel and the mouth of the flask was there to order to relieve any increase in pressure caused by hot filtrate. 2. Enumerate two techniques that can help prevent premature recrystallization. Explain each one. What is the consequence of premature recrystallization?
Heating the solution will prevent premature recrystallization before the filtration. Filtering the solution while it is still hot will allow the solution to be filtered thoroughly. The washing of the solution with hot water will prevent the premature recrystallization of the solution in the container thus making the recrystallized benzoic acid more pure.
The type of funnel used in the filtration will also help to prevent premature recrystallization of the solution. Using a wider stem funnel is less prone to premature recrystallization inside the stem because the filtrate can cool as it passes through the stem since cooler temperatures are where crystals are likely to form.
Premature recrystallization will have a consequence of lower yield of
ANSWERS TO QUESTIONS 1. How does the use of fluted filter paper hasten filtration? Why is it advisable to place a small piece of wire between the funnel and the mouth of the flask during hot filtration?
Fluted filter paper is effective in preventing crystal formation in the filter paper. It is also often used in filtering hot saturated solution used during crystallization. One major advantage of a fluted filter is that it increases the speed of filtration. The crisscrossing of the folds help alleviate the pressure to make the flow of filtration faster. The surface are of the filter paper also increases thus more solvent seeps and enter the flask. Fluted filter paper is also used in filtration that needs the solute instead of the solvent. In order to get the recrystallized benzoic acid, fluted filter paper was needed to be used.
The small piece of wire attached between the funnel and the mouth of the flask was there to order to relieve any increase in pressure caused by hot filtrate. 2. Enumerate two techniques that can help prevent premature recrystallization. Explain each one. What is the consequence of premature recrystallization?
Heating the solution will prevent premature recrystallization before the filtration. Filtering the solution while it is still hot will allow the solution to be filtered thoroughly. The washing of the solution with hot water will prevent the premature recrystallization of the solution in the container thus making the recrystallized benzoic acid more pure.
The type of funnel used in the filtration will also help to prevent premature recrystallization of the solution. Using a wider stem funnel is less prone to premature recrystallization inside the stem because the filtrate can cool as it passes through the stem since cooler temperatures are where crystals are likely to form.
Premature recrystallization will have a consequence of lower yield of