1 / 10

Colloids

Colloids. Solutions. Have small particles (ions or molecules) Are transparent Do not separate Cannot be filtered Do not scatter light. Colloids. Have medium size particles Cannot be filtered Separated with semipermeable membranes Scatter light (Tyndall effect). Colloids.

idalia
Télécharger la présentation

Colloids

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Colloids

  2. Solutions • Have small particles (ions or molecules) • Are transparent • Do not separate • Cannot be filtered • Do not scatter light. LecturePLUS Timberlake

  3. Colloids • Have medium size particles • Cannot be filtered • Separated with semipermeable membranes • Scatter light (Tyndall effect) LecturePLUS Timberlake

  4. Colloids • In a solution, dispersed particles are molecule-sized (roughly 0.1 nm). • In a colloid the dispersed particles are 1 – 1000 nm.

  5. The Tyndall Effect Light scattered by the (larger) colloidal particles makes the beam visible.

  6. Examples of Colloids • Fog • Whipped cream • Milk • Cheese • Blood plasma • Pearls LecturePLUS Timberlake

  7. Suspensions • Have very large particles • Settle out • Can be filtered • Must stir to stay suspended LecturePLUS Timberlake

  8. Examples of Suspensions • Blood platelets • Muddy water • Calamine lotion LecturePLUS Timberlake

  9. A Suspension and a Colloid Suspended particles (sand) are far too large to show on this scale.

  10. Formation and Coagulation of a Colloid When a strong electrolyte is added to colloidal iron oxide, the layer of charge on the surface of each particle is partially neutralized… …and the colloidal particles coalesce into a suspension that settles quickly.

More Related