Gravity Filtration in Laboratory Procedures

What is the purpose of wetting the filter paper with the dominant solvent before filtering?

What is the first step in folding filter paper?

What should you do with the torn-off corner if the filter paper has been pre-weighed?

How many thicknesses of paper should line one half of the cone when fitting the filter paper in the funnel?

What can be done to prevent splattering when pouring the liquid during filtration?

Why is it recommended to allow most of the solid to settle before pouring the mixture into the filter?

Gravity Filtration

Gravity filtration involves using a polyethylene or glass funnel with a stem and filter paper.
Filter paper has varying pore sizes, ranging from small to large, to accommodate slow to fast filtering.

Folding Filter Paper

Fold the paper in half, then in quarters, and finally tear off the corner to ensure a snug fit in the funnel cone.
If the paper has been pre-weighed, save the torn corner piece to add to the post-filter weighing to avoid errors.

Setting Up the Filter

Wet the filter paper completely with the dominant solvent or solvents in the mixture to be filtered.
This step adheres the filter paper to the funnel walls, preventing solid from escaping.

Preparing for Filtration

Allow most of the solid in the mixture to settle before filtering.
Pour the supernatant liquid (the liquid standing over the solid in a mixture) through the filter first.
This allows the initial part of the filtration to proceed faster and may prevent clogging of the filter by the solid.

Pouring the Liquid

Pour the liquid down a glass rod to prevent splattering.
Ensure the funnel stem rests against the side of the beaker to prevent splattering.

This quiz covers the use of gravity filtration in laboratory procedures, including the equipment and techniques involved. Learn about the different types of filter paper and how to properly fold and use them.