Separation Techniques

Master separation techniques like filtration and evaporation. Learn to separate mixtures in science!

Separating solids from liquids – filtration Visit the BBC Bitesize website to complete the questions below. Separating mixtures - Bitesize Complete the table below. Separation Technique Types of solution Description Filtration Insoluble Solid - Liquid Sand and water Evaporation Soluble Solid - Liquid Copper sulfate and water Distillation Liquid - Solution Water and salt solution Chromatography Dissolved substances Plant dyes / Inks Sieving Solid - Solid Rocks and sand Methods for separating mixtures Explore the eSchoolToday website to answer the following questions. Methods for separating mixtures Complete the passage below by filling in the missing words. FiltrationThis process involves the use of a filter paper placed in a filter funnel. The funnel is placed in a beaker and the mixture of water and sand is poured into the funnel. The liquid part drains through the filter paper into the beaker, leaving the solid sand particles trapped on the filter. In filtration, the liquid part collected is called the filtrate and the solid bit that remained on the filter paper is called the residue.EvaporationEvaporation is the process by which water (and other liquids) changes from a liquid state to a vapor or gas state. Evaporation is great for separating a mixture (solution) of a soluble solid and a solvent. The process involves heating the solution until the solvent evaporates (turns into gas) leaving behind the solid residue.Simple distillationThis method is best for separating a liquid from a solution. In a way, the concept is similar to evaporation, but in this case, the vapor is collected by condensation. For example, if you want to separate water from a salt solution, simple distillation would be great for this.For example: A beaker of salt solution is heated to the boiling point of the liquid. As it boils, the liquid turns into vapor (gas). The vapor is directed through tubes (condenser) connected to another beaker. As the vapor goes through the tube, it is cooled down by running cold water around the tubes. This forces the temperature of the vapor to fall, causing the gas to turn into liquid again (condensation). The liquid is pure at this point, as it is free from salt. The process continues until all the liquid in the solution turns into vapor, leaving the salt residue. The distilled liquid is called a ‘distillate’.ChromatographyThis method is often used in the food industry. It is used to identify chemicals (coloring agents) in foods or inks. For example, if a scientist wants to know how many substances are in a particular blob of ink, paper chromatography can be used.For example: A blob of ink is smeared on a special paper called filter paper. The paper is placed in a trough of solvent. The solvent used depends on the chemicals in the ink blob. As the paper gets soaked upwards, it attracts the various chemicals in the ink blob. Because different chemicals have different rates of attraction to the solvent, the chemicals will travel upwards in different amounts. Sometimes, a chemical may not react at all. If a different solvent is used, all the various chemicals may travel at a completely different rate. How do we separate the seemingly inseparable? Watch the video to answer the questions below. List 3 properties that can be exploited to separate substances. Match the term to its use. Reverse osmosis Separate salt from see water Rotational force Separate red blood cells from plasma Distillation Separate petroleum from crude oil Sieving Remove gold from sand True or False. Chromatography is a chemical separation technique. True False Plenary Puzzle Assemble the puzzle to solve the "Who am I?" below.