Gravity Filtration

Video. Assembling the equipment.

IMAGE. The assembled gravity filtration equipment.

Video. Self Check video.

Rest the funnel in a ring stand. Check to make sure that the funnel is secure and will not tip over during the filtration.

If the funnel is too small for the ring stand available to you either place a clay triangle on the ring and rest the funnel in the triangle or rest the funnel in the neck of an Erlenmeyer flask. If the latter technique is used, place a paper clip between the funnel and the flask. WHY? Resting the funnel in the Erlenmeyer flask is not recommended since the funnel is not very stable when resting in the neck.

Place the filter paper in the funnel and moisten the paper with a small amount (1-3 mL) of the solvent used. Allow the solvent to pass through the filter paper, but do not allow the paper to dry out before you begin the filtration. The moistened filter paper should help keep the paper in place for the filtration.

Once the paper is wetted and there do not appear to be any channels (the paper is not torn) for the solid to pass through to the receiving flask, the equipment is prepared for the filtration.

View the video titled "Self Check video". What does the student need to do? Answer