Separating Mixtures Name: Class:
Directions: Match the words with the big ideas by writing the letter beside the idea. Use the same words in the short article below. Use key words and phrases from the article below to help. you. A B A C solid liquid gas To pull two or more things apart A mixture of 2 liquids that don t dissolve A mixture where a solid dissolves in a liquid D E F G H I J mixtures separated particles miscible immiscible emulsion dissolved Hard and firm A mixture where a solid doesn t dissolve in a liquid A tiny piece of anything A wet substance To divide into parts Two or more things mixed together A substance like air Mixtures are not a chemical reaction. are formed when two or more substances are combined. The _ are often spread evenly or _ throughout the mixture, but the particles can usually be _ by filtration or other methods. The particles may be, _, or _. There are 3 kinds of mixtures.. The first is a mixture. This is when the particles of a mixture are evenly spread through a mixture, such as salt mixed in water. The second is an mixture. This is when particles are not spread evenly throughout the mixture., such as sand in water. The third kind is an. This is a mixture of two liquids in which the particles of the liquids are evenly distributed, such as dish soap in water. 53
Boys and girls, Did you know that mixtures are not a chemical reaction? Mixtures are formed when two or more things are combined. You can mix a solid with a liquid, liquid with a liquid, solid with a solid and gas with a gas. 1. Miscible mixtures Example: salt in water the salt dissolves in the water 2. Immiscible mixtures Example: sand in water the sand sinks to the bottom 54
3. Emulsions Example: vegetable oil in water the oil mixes then floats to the top Unscramble the words to find the secret sentence. 55
Use a plastic cup, spoon, magnifying glass, salt, pepper, vegetable oil and water to look at the 3 different kinds of mixtures. 1. 2. Step 1. Put about 5cm of water into the plastic cup. Step 2. Put one spoon of salt into the cup of water. 3. 4. Step 3. Stir until the salt is dissolved in the water. Step 4. Study the mixture with a magnifying glass. 5. Step 5. Draw the experiment in the box and answer the questions. 56
Salt mixture 1. Can you see any grains of salt on the bottom of the cup or did it dissolve completely in the water? 2. Can you see any un-dissolved grains of salt in the water or is the water clear? 3. Stir one more teaspoon of salt into the cup. Did all of the salt dissolve in the water? 4. Can you see any salt on the bottom of the cup or in the water? 5. Is the water clear or cloudy? 6. 7. Step 6. Add some black pepper to the cup. Step 7. Stir the pepper and salt mixture. 8. Step 8. Draw the experiment in the box and answer the questions. 57
Pepper and Salt mixture 1. Does the pepper dissolve into the water? 2. What do the flakes of pepper do in the water? 3. Describe the difference between the reaction of salt and pepper when stirred into the water. 9. 10. Step 9. Put some vegetable oil into the mixture and stir. Step 10. Draw the experiment in the box and answer the questions. 58
Pepper, Salt and Vegetable oil mixture 1. Does the vegetable oil spread throughout the water? 2. Can you see the vegetable oil in the water? 3. Put your finger into the mixture. Is the vegetable oil spread throughout the water? 4. What happened to the pepper when the vegetable oil was added to the mixture? Extension Let the oil settle to the top again. Stir the fluids 15 times. Time how many minutes and seconds it takes for the oil to settle on top of the water. minutes seconds Look at the table of everyday items. MISCIBLE, IMMISCIBLE or EMULSION. Put a cross in the correct box if it is a miscible immiscible emulsion cola dish soap coffee salt water milk oil salad dressing lemon juice 59
Use salt, flour, water, food coloring, bowl, cream of tartar and hot plate to make some fun play dough. 1. 2. 3. Step 1. Put 100g of salt and flour into a bowl. Add 4 teaspoons of cream of tartar. Mix well. Step 2. Add food coloring to 100ml of water and stir. Step 3. Add the colored water to the mixture and stir it until you can t see any flour. 4. 5. Step 4. Put the bowl onto the hot plate. And stir until it turns into thick dough. Step 5. Put the dough on to a dish and let it cool. 60
Boys and girls, Did you know that most mixtures can be separated? The kind of separation method depends on the kind of mixture it is. Let s look at some common separation methods. 1. Paper Chromatography This 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. 2. Filtration This is a more common method of separating an insoluble solid from a liquid. An example of such a mixture is sand and water. Filtration is used in water treatment plants, where water from rivers are filtered to remove solid particles. 61
3. Evaporation 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. 4. Distillation This 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. 5. Magnetism Magnetism is ideal for separating mixtures of two solids with one part having magnetic properties. Some metals like iron, nickel and cobalt have magnetic properties whiles gold, silver and aluminum do not. Magnetic elements are attracted to a magnet. 62
6. Separating funnel In this technique, two liquids that do not dissolve very well in each other (immiscible liquids) can be separated by taking advantage of their unequal density. A mixture of oil and water, for example, can be separated by this technique. Empty out the solids that are in your bag. Draw your mixture. Now, separate your mixture into the different kind of solids. 63
Across 1. Something which has particles close together 8. Mixture where two liquids mix and then separate 10. Something which has particles moving quickly everywhere 11. Method of separating a mixture starting with E 14. two pull two things apart Down 2. Method of separating a mixture starting with D 9. Mixture where a solid or liquid dissolves 3. Mixture where a solid sinks to the bottom of a liquid 12. Method of separating a mixture starting with M 4. When two or more things are mixed together 13. A tiny piece of anything 5. Method of separating a mixture starting with F 6. Something which has particles loosely together 7. When a liquid or solid disappears in another liquid 64
Use a magnet, plastic wrap, iron filings, salt, filter paper, sand hot plate, water and pot to separate three solids. Before we begin this experiment we need to look at some important information. In this experiment, we will use three solids, all with different characteristics. 1. Iron is a magnetic solid which doesn't dissolve in water. 2. Salt is a non-magnetic solid which does dissolve in water. 3. Sand is a non-magnetic solid which doesn't dissolve in water. Material State Magnetic Dissolve in water Iron Salt Sand 1. 2. 3. Step 1. Wrap a magnet in plastic wrap. Move it through the mixture of the 3 solids Step 2. Put the iron filings in a pile on the plate. Step 3. Put the remaining solids into a beaker and add 50ml of water. 65
4. 5. 6. Step 4. Stir the mixture. Step 5. Using a funnel filter the mixture through some filter paper into a bowl. Step 6. Put the sand onto the plate with the iron filings. 7. 7. Step 7. Place the pot on the hot plate and wait till the water has evaporated. Step 8. Put the salt onto the plate. What happened? Draw three pictures in the boxes showing the three processes used to separate the mixture. Magnetic Filtration Evaporation 66
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