How To: Perform Vacuum Filtration in the Chemistry Lab

Find out how everything in a chemistry lab works, from pipettes to burners to recrystallization to storage. You'll get precise instructions on how to work and perform certain scientific duties in the chem lab, whether it's chemical or just ordinary high school science.

Watch this video on how to perform vacuum filtration in the chemistry lab. As an example of how to separate supernatant from a precipitate by vacuum filtration, the movie explains the separation of 4-methoxy-2-nitroacetanilide.

This filtration technique uses a water-jet pump or an aspirator. The reduced pressure makes the filtration fast. This is suitable for the separation of a precipitate consisting of light and fine particles. Organic precipitates in synthetic experiments are usually collected by vacuum filtration. Because a flat filter paper is employed, the collected precipitate is easily raked. Understanding how to use a three-way stopcock is desirable.