RDGfiltration - Filtration Techniques Revised 5/05/06...

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Filtration Techniques Revised 5/05/06 FILTRATION TECHNIQUES Filtration, the technique used to separate solids from liquids, is the act of pouring a mixture onto a membrane (filter paper) that allows the passage of liquid (the filtrate) and results in the collection of the solid. Two filtration techniques are generally used in chemical separations in general chemistry lab: "gravity" filtration and "vacuum" filtration. Gravity Filtration Gravity filtration uses a polyethylene or glass funnel with a stem and filter paper. Filter paper can have pore sizes ranging from small to large to permit slow to fast filtering. The paper is folded in half (Figure 1), then folded in quarters, and the tip of one corner is torn off to allow for a snug fit in the funnel cone. (If the paper has been pre-weighed, the torn corner piece must be saved to add to the post-filter weighing to avoid any errors.) The paper cone is fitted to the funnel so three thicknesses of the paper line one-half of the cone and one thickness lines the opposite half (Figure 1). Now place the funnel into a beaker and wet the filter paper completely Open filter paper cone and line funnel Tear off corner Save corner if filter paper has been weighed. Fold paper in quarters Fold paper in half Figure 1: How to Fold Filter Paper with the dominate solvent or solvents in the mixture to be filtered. This step adheres the filter paper to the funnel walls preventing solid from escaping. Then, support the funnel with a clamp 1
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Filtration Techniques Revised 5/05/06 or ring (if necessary) and place a clean beaker beneath the funnel so the stem rests against the side of the beaker (this prevents splattering). Before filtering, allow most of the solid in the mixture to settle.
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This note was uploaded on 11/23/2010 for the course CHEMISTRY Chem 1LC taught by Professor Dr.kimberlyedwards during the Fall '10 term at UC Irvine.

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RDGfiltration - Filtration Techniques Revised 5/05/06...

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