Overview
This lecture explains decantation, a method used to separate mixtures, specifically solids from liquids and immiscible liquids.
Definition and Purpose of Decantation
- Decantation is separating the components of a mixture by pouring out the liquid without disturbing the sediment or lower layer.
- The process is used to separate solids from liquids or two immiscible liquids.
Examples of Decantation
- In a sand and water mixture, sand settles at the bottom and water is gently poured off into another container.
- When washing rice before cooking, water containing impurities is decanted, leaving clean rice grains behind.
- In oil and water mixtures, oil forms a layer above water and can be separated by pouring it off carefully.
Processes in Practice
- Let mixtures settle so the heavier component sinks, then slowly pour off the top layer.
- Do not disturb the sediments or the lower liquid while decanting.
- Decanting removes impurities or separates components based on density.
Key Terms & Definitions
- Decantation — the process of pouring off a liquid to separate it from sediments or a different liquid layer.
- Sediment — the solid particles that settle at the bottom of a liquid mixture.
- Immiscible liquids — liquids that do not mix, forming separate layers (e.g., oil and water).
Action Items / Next Steps
- Practice decantation with sand-water and oil-water mixtures at home.
- Prepare to discuss the advantages and limitations of decantation in class.