The substances in a solution are mixed on the level of individual particles. (Hint: which liquid has the lowest boiling point?) What would be the best method for separating the undissolved solids from the liquids in the mixture? That means we do not need to use chemical reactions to separate them. Learners should write SALT, ETHANOL and WATER in block 3. The components in a mixture are not chemically joined; they do not change their chemical identities and they retain their physical properties as well. Fill these into the table. They still have the same properties they had before they were mixed. You might think that mixtures that are so 'well-mixed' are impossible to separate! Medicine that is old or expired should never be repurposed. The table below contains a list of mixtures. Learners should write WATER and SALT in block 9. The vacuum cleaner has a fine filter in it which traps the dust particles. Careful laboratory practice will not only ensure your own safety, it will also set a good example to learners. How does the vacuum cleaner separate the dust from the air? 'There is no away' and 'There is no Planet B' refers to the same issue, namely that everything that we throw away remains part of our environment. Have you ever seen smoke from a fire? We can separate iron from a mixture of sand and iron, as only the iron is attracted to the magnet. to personalise content to better meet the needs of our users. That is why mixtures can be separated using _____ methods. Chromatography is a method for separating coloured substances into individual pigments. Learners should write FILTRATION in block 1. The water that is lost through evaporation can be condensed on a cold surface. What does the container look like? Please press Reload to sign in to the Veative Console again. Yes, as long as there are not too many of them to sort. In this case it would be better to use pure sea salt. You would probably not consider sorting sugar and sand grains by hand. Carbon dioxide is present in much smaller quantity. Now draw the container with a mixture of ethanol and water in it. Choose the correct word to complete the sentence from the following list: colours; boiling points, tastes. If they look different, and you have used the same pen, why do you think that is? The small clay particles become suspended in the water. Learners should generate suggestions centred on reusing, recycling and repurposing. That is why mixtures can be separated using physical methods. This example might be a sensible inclusion since it would serve as early introduction to households acids that will feature prominently in the next chapter (Acids and Bases). The image below indicates where the arrow should be drawn: Can we see most gases? Discarded plastic pollutes rivers and other natural habitats. Lay a large round piece of filter paper on a smooth non-absorbent surface, like the surface of your desk, for instance. Does the salt evaporate with the water?

Constitutents , Magnet , Methods Of Separation, Google Cardboard , Google Daydream , Samsung Gear VR , Oculus Go , Pico , EduPro. The mixture contains the following components: Your job is to design a procedure for separating the mixture into its individual components. Use a black pen or marker to draw a line across one end of the paper strip, 2 cm from the end. Many things can be reused or recycled. A solvent is usually a liquid, but can also be a solid or a gas. [4 marks], Write a sentence to say how you would dispose of each of the following non-recyclable materials: vegetable peels; old running shoes; expired medicine. Three different colour bands mean there are (at least) three different pigments in the ink. We would want separate the water from the solid material (sand or clay) before using it! Suppose you were given a basket of apples and oranges. Sometimes people create machines to perform tasks for them, like this Skittles sorting machine. What type of mixture is the muddy water in the glass an example of? When the 'particles' in the mixture are relatively large and when there are not too many of them to sort. Here is how it works: The mixture of the two liquids is placed in the distillation flask and heated to the lowest boiling point. Write a short description of this career. Once again they will be confronted with the realisation that the solution does not have visible features. To remove the tea leaves from the tea before drinking it. Alternately, you could prepare the mixture for them to look at it before drawing it: To help you design your procedure, here are a few guiding questions and a template for your flow chart: What is the physical state (solid, liquid or gas) of each of the components in the mixture?

We will learn about elements and compounds in the next chapter. Activity: What if we want to keep both the water and the salt? Why do you think that is necessary? A mixture consists of two or more components that have different physical properties. Copyright 20082022 eSchoolToday in association with Draw it on your page. Learners should write MAGNETIC SEPARATION in block 4. For softer papers you may need longer strips of paper and taller containers, since the liquid is carried up the paper much faster. Sugar and sand grains are too small to be sorted by hand, and they look very much the same. They would throw the mixture into the air and the wind would blow away the lighter chaff, but not the heavier grain. Expired medicine should be taken to the pharmacy. Place this out in a sunny spot for the duration of the lesson and allow the water to evaporate. Perhaps the following diagram will help you to formulate a plan. Since the salt has not evaporated, it stays behind in the distillation flask. The magnetic properties of the metals allowed them to be separated in this way. Keep in mind that some mixtures that we expect to be solutions end up being suspensions. The rate of evaporation will depend on how hot and humid it is on the day you do this. Who is responsible for the disposal of waste materials? When working with ammonia, take care to work in a fume hood or in a well-ventilated space. If the magnet is held in the mixture the iron filings will cling to the magnet, but the sulfur will stay behind in the bowl. Some metals like iron, nickel, and cobalt have magnetic properties whiles gold, silver and aluminum do not. When you have finished comparing your chromatogram with those of the rest of the class, you can either stick your chromatogram in the space below, or draw a picture of it in the space. Discuss this with your teacher and classmates and when you have agreed on an answer, draw an arrow onto the picture to indicate the water vapour. Let's find out. The masks help to clean the air before it enters the respiratory tract. In your group, spend 5 minutes discussing the posters and what you think they mean. You should not inhale the vapours of these solvents. Write them in the space provided. However, it is not critical at this stage and you do not need to go into detail. Would hand sorting also be a practical way to sort out the mixture of rice and lentil beans in the picture below? All of the liquid with that boiling point will evaporate, condense in the Liebig condenser, and pass into the receiving flask. Discuss in your group, or with your partner, what each mixture consists of. Gas-liquid mixtures: spray deodorant and air freshener, Gas-solid mixtures: smoke, dust cloud and foam plastic, Liquid-liquid mixtures: Clear fruit juice, hair oil, Solid-liquid mixtures: Salty water, paint (an emulsion/suspension of solid pigments particles in water or oil), cloudy apple juice (tiny bits of pulp are solid, and suspended in the juice). Sorting and classifying, communicating, group discussions, 2.2 Methods of physical separation (4 hours), Activity: Thinking about sieving and filtering, Activity: Thinking about magnetic separation. It is relatively cheap, easy to assemble, and requires no electricity. In some suburbs, recycling is actively encouraged and special transparent recycling bags are provided for this purpose. Chapter 8: Acids, bases and neutral substances. Solutions are clear; that means we can see through them. Write an explanation below. Chemists study various chemical elements and compounds, their properties and how they react with each other. When the particles in a mixture are too small to be caught by a sieve and when the components of the mixture are in different states, we can separate them by filtration using a filter. Learners should write DISTILLATION in block 5. Does the mixture become muddy? How would you separate the mixture of beads in the picture below into the different colours? South Africa gets it salt from inland salt pans, coastal salt pans and seawater. It is not likely to cause burns but ammonia fumes can irritate the mucous membranes of your nose. In the diagram below, iron filings and sulfur have been mixed. dissolved (in solution with the water and salt), dissolved (in solution with the ethanol and salt). What happens to a liquid when it boils? If the class is divided into small groups and each group gets a different black marker to experiment with, the chromatograms can be stuck up on the wall afterwards for everyone to see and compare. Activity: How can we separate two liquids with different boiling points? (Hint: this process is the same as the one in block 7.) This is encouraged and the activities in these workbooks can be adjusted slightly to work with whichever equipment and apparatus you have available to you in your school. done by thinking of the materials which you use in everyday life and making a plan! This kind of mixture is called a suspension. There is also potential to do this activity as a group. We can use the same distillation method that we used for separating seawater, to separate the two liquids. Learners may have interesting opinions about this question, and hopefully it will get them thinking about creative ways of reusing and repurposing waste. When the 'particles' in the mixture are very small, and in different states. Allow the liquid to soak up into the paper, rising through the inked line. We will only see the water when it starts to condense. Is the recyclable waste collected from your home or do you have to drop it off at a container or a depot? We could evaporate them, but then they would be lost. The yellow pigment is moving the fastest because it has travelled the longest distance. Do you think picking the pebbles out by hand would work? Place a drop of water in the centre of the ink spot.

However, sometimes we need to separate mixtures into their components.

If you study chemistry after you have finished school, you can work as a researcher, a laboratory technician, a science teacher and many other important and stimulating jobs! Allow learners to discuss this for a while. After a number of runs, all the sand will be free from any iron filing. Laboratory Whatman filter paper no. What do you think will happen when the mixture reaches a temperature of 78C? Get learners to taste the salt water before boiling and then getting them to taste the condensed water afterwards. You can put the learners at ease and tell them it is not important for them to know what this means yet. A mixture of vinegar and water is clear, and that is a clue that the mixture is a solution. What colour are the magnetic grains and which container do they fall into? Clothes that are too worn can be turned into cloths for washing the car or the windows. How would you sort them? Label this on the diagram. The non-magnetic grains are yellow-orange and fall into the container on the left. by this license. By looking for matching chromatograms, learners can say which group had the same brand of marker, or which markers are filled with the same ink. Pebbles are even larger. You will notice that the magnetic elements (iron filings) will be attracted to the magnet over it. A solvent is a substance that dissolves a solute, resulting in a solution. An artists, Berndnaut Smilde, uses a fog machine to make small clouds inside a room which only last a few seconds. Do you think the ethanol will start to boil? Otherwise there are alternative materials and equipment that you can use. A mixture can contain solids, liquids and/or gases. Soil can contain clay, sand and small pebbles. Let's discover the possibilities of chemistry! Which colour pigment is moving up the paper at the fastest speed? It probably is not a good idea to hand sort as it would take too long. What remains after the undissolved solids have been removed from the mixture? After completing this module, you will be able to: - Describe the procedure to separate the constituents of a mixture that are attracted toward a magnet. Poor waste management leads to negative consequences for humans, animals and the environment. It is also an open-source project which means that anybody can use the design and replicate, modify or upgrade it, but not sell it for profit. This is a revision of the types of mixtures that one can get, which has been done in Gr. Why do you say so? Can you remember the activity from Gr. Summary of separating mixtures in short slideshows Safe laboratory practice is extremely important. Get your learners to act out the word 'mix'. Find out more about the distillation of crude oil in this video. This is not actually water vapour, which would be invisible to the human eye. Write the names of the two undissolved solids in blocks 6 and 7. For that reason, mixtures can be separated using physical methods. It is a mixture of solid and liquid, it is a suspension. Secondly, most solutions that learners will be able to think of are essentially solid-liquid mixtures at the fundamental level. Would hand sorting be a practical way to sort the pebbles out of a large pile of sand? Before you start, imagine what the mixture would look like. The particle model of matter will only be dealt with in detail in Gr. Do you know which materials from household waste can be recycled? The second liquid will evaporate, condense in the cooler and flow into the clean receiving flask, leaving the final component in the mixture in the distillation flask. One of the central ideas in this section is that the components in a mixture are not chemically joined. We call the separated components fractions, and the process, fractional distillation. It is described as an eco-distiller that runs on solar power. Write the word below. Can you remember what a mixture is called when a solid is suspended in liquid? Crude oil is separated into different components using distillation. Why do you think they did this? Some metals like iron, nickel, and cobalt have magnetic properties whiles gold, silver and aluminum do not. Draw a picture of the a clear container and the different contents in the mixture in the space. Magnetism is ideal for separating mixtures of two solids, with one part havingmagneticproperties. Leave the door and windows open, so that the fumes do not linger. Mixtures are very useful. Seawater is allowed to stand in shallow pans. The condenser is designed in such a way that cold water can flow through the space between the tubes. Where do you think our rubbish goes once we 'throw it away'? Learners should note that black ink is actually made up of a number of different coloured pigments. Some of these are: pollution of the soil, water resources and the environment; health hazards and the spread of disease; land wasted when it is used to dump or bury garbage (landfills); and. Your descriptions of the career you are interested in: We looked at physical methods to separate mixtures and these are shown in the concept map. It works like this: Let us take a mixture of sand and iron filing for example. The process is evaporation. How can we separate the components in a solution? For example, if you do not have a Liebig condenser, you can use a piece of copper pipe. Suppose you mix some water and some ethanol. You would probably pick out all the oranges from the apples by hand. The apparatus used in this technique is called a still. The most practical method would probably be to hand sort them into different colours. When we want to separate a mixture, we can use the differences in the physical properties of the components of the mixture to separate the components from each other. Chromatography comes from from the Greek words chroma (meaning 'colour') and graph (meaning 'to write'). Old clothes and other textile items; old shoes. Science can help us solve problems in the world around us. You can also use a beaker or glass of salt solution over a bunsen burner and use a cold piece of glass or mirror to condense the water and collect it in another beaker. A suggestions is to do a demonstration of this in class if you can get a kettle and plug it in to show learners the colourless steam at the spout of the kettle. Ammonia is a dissolved gas and a weak base. (Most of it would sink to the bottom. When they are faced with a solution (water and sugar, for instance) they might notice that there are no visible features to draw. To set up a filter (as shown below), place a folded piece of filter paper in a funnel and place the funnel into a flask. Are they the same or are they different? In the picture, the salt-water solution is heated in a kettle, and a metal plate (with some ice inside to keep its outer surface cold) is held in the water vapour that is escaping from the spout of the kettle. Here is an additional, optional activity, which you could get learners to do as a homework task. The one liquid component in milk is water, and the other is fatty oil. By the end of a day it can provide bacteria-free, salt-free water that is suitable for drinking. Learners should write IRON FILINGS in block 6 and SAND in block 7. This exercise may seem trivial but their attention will immediately be focussed (and their learning enhanced) if they are engaged in this way. Learners were exposed to similar images in Gr. The substances cannot be separated by filtration (dealt with later in this chapter). When is magnetic separation suitable for separating the components in a mixture? Learner-dependent answer. (One way to recognise an emulsion is that it is opaque). Draw pictures of your chromatograms in the space below. Do you think it is possible to stop throwing things away altogether? The water or oil in the paint helps us to spread the pigments more evenly over the surface that we want to cover and binds the pigments tightly so that the paint forms a protective layer. Now that we have learnt about some of the different ways in which mixtures can be separated, we are going to apply what we know to separate a mixture made of many components. AIM: To separate the pigment components in ink using different liquids. ), Now add the salt. Can you think of a practical way to sort stones or pebbles from sand? 'There is no Planet B' is also a play on words that refers to the well-known notion of a 'Plan B' that can be reverted to if the original plan (plan A) fails. Write the name of this process in block 4. Learners might make stirring motions with their arms. Suspensions are opaque; that means they are cloudy and we cannot see through them very well. [3 marks]. Learners may suggest filtration (filtering) as a method for separating the sand and water. Alcohol and acetone are flammable and should be kept away from heat and flames. The strip on the left shows the chromatogram at the start of the experiment, the strip in the middle shows the chromatogram halfway through the experiment, and the strip on the right shows the chromatogram at the end of the experiment. What are the substances found in soil? No. Discuss this with your class and give an answer below. A useful site to find out more about some chemistry-related careers. Many things around us occur naturally as mixtures: salty sea water, moist air, soil, compost, rocks (mixture of minerals) to name a few. Like suspensions, emulsions tend to be opaque. It might help to place the magnet in a small plastic bag so the iron filings are attracted to the magnet, but do not stick to it. Here are a few ideas, but they only need to choose one: Once learners have created their posters, you can stick them up around the classroom and they can also do a short report back to the class. (You could also use this apparent paradox as the basis of an extension activity about what appearances allow us to infer in certain situations.). It then runs off the plate and into the collection beaker. Are all liquid-liquid mixtures emulsions? No. Nowadays most people use tea bags to make tea, but there was a time when people brewed tea from leaves and then poured the tea through a sieve into the cup. The small cloud of in front of the kettle is actually a cloud of micro-droplets of liquid water suspended in air. If you have the equipment to set up this distillation process, then you can demonstrate it in class. Learners should write ETHANOL in block 8. How could we separate the undissolved solids? Suppose we want to separate two liquids using distillation as separation method. A wonderful example of science as art!

We are going to explore this in the next investigation. Clean air comes out of the vacuum cleaner. At the end of the lesson, collect the pan and show the dried salt that is left behind, just as in a salt pan. Distillation is the separation of one substance from another by evaporation followed by condensation. You can get learners to prepare a few questions beforehand; for instance, you could ask them about their work, their training and what they think are the qualities needed if one wanted to become a chemist. Old jerseys can be sewn into blankets or other items. Just remember to make an appointment first! Write a short paragraph (3 sentences) to explain how salt is produced from seawater. (It would sink to the bottom. The diagram below shows how a gas mask works. These are the undissolved solids. United States. Some things we can't detect or taste, for example, if we were using sea water. Land is wasted when it is used to dump or bury garbage (landfills). The clean air is able to get through the filter, but the dust is left behind. How would you do that? When some liquids are suspended in liquid, we call the mixture an emulsion. What happens when sugar is mixed with water? When the components of the mixture have different sizes and there are many of them to sort. Point to it with your finger. Magnetic elements are attracted to a magnet. All Siyavula textbook content made available on this site is released under the terms of a Each of the fractions that are eventually collected contain one kind of hydrocarbon combination. You could even build a story around the investigation: Stage a murder mystery in which the murderer can be identified by his (or her) black pen. Write the name of the process in block 10. Physical methods can not be used to separate elements that are chemically joined. Hand sorting is a suitable separation method for a mixture that contains a relatively small number of large items. Separating ink by chromatography, hypothesising, doing investigation, observing, recording information, comparing, interpreting information. Explain your answer. Demonstrating distillation using Liebig condenser. Learners should write WATER in block 11 and SALT in block 12.

Do you think separation by evaporation would be a good method to separate a salt-water-solution if you wanted to keep both the salt and the water? Take note that the video repeatedly mentions 'hydrocarbons'. The mixture of clay or sand with water is muddy. Would you be able to see the ethanol AND the water when they are mixed? What are the four main categories? Do you think it would work for a sugar and water solution? What methods can be used to separate a mixture into its original components? How would you find out? Soil can also contain bits of plant matter. Look at the picture of the chromatogram below. You can also use a clothes peg to hold the strip in place while drying. Creative Commons Attribution License. This will only be possible if the two liquids have different [1 mark], How many different pigments does the black ink consist of? Do you know what chemists do? You can get learners to label the suspension, the filtrate and the residue on this diagram. Discuss this in a group and write them into the table. Muddy water is not good to drink. The sand and iron filings are undissolved. Name the solids that will not dissolve in the mixture. Your team has been given an important job. Over time, some of our things get old and break and we need to throw them away. Are all liquid-liquid mixtures opaque? Pigments migrate at different speeds because of differences in their properties: large pigment particles tend to move more slowly. Alternatively, you could visit the chemist at their workplace and ask them to show you around.

Why do you think so? This also makes science more accessible to everyone. Similarly, substances containing alcohol should be used in a well-ventilated space, but these are also flammable, so avoid using them in the presence of open flames. But what does 'away' mean? Demonstrate this in a lesson by dissolving some salt in water in front of the class at the beginning of the lesson. Nail polish remover contains acetone. Nitrogen gas and oxygen gas. Let us look at some of the most commonly used methods of physical separation. In this short activity, we are going to think about creative ways of dealing with household waste items that are not in the 4 categories discussed above. Another suggestion is to get learners to also do the research to see how to make their own distillation apparatus, specifically looking at materials which are easy and cheaper to come by. Learner's answer should contain the following elements: A vacuum cleaner creates a suspension of dust in air as it sucks up the dust on the floor. Can you think of a way to modify the method so that the water that evaporates is not lost? It is always advisable to wear latex/nitrile gloves (available from pharmacies) to prevent the absorption of hazardous substances through your skin. For instance, sugar dissolved in water would go in the middle block of the bottom row, to show that it is a solid (sugar) mixed with a liquid (water). The principle is exactly the same, except that we will distill the mixture more than once. Fill these in the concept map. A salt pan is a shallow dam in the ground where salt water evaporates to leave a layer of dry salt. When sea water is allowed to stand in shallow pans, the water gets heated by sunlight and slowly turns into water vapour, through evaporation. The clear liquid that has passed through the filter paper is called thefiltrate and the particles that are left behind on the filter paper is called the residue. Which liquids are in the container? Wear safety goggles to protect your eyes from harmful chemicals. 'Mixtures' was first introduced in Gr. 6 Matter and Materials. Iron filings are attracted to the magnet, but sulfur is not. Evaporation by itself is not a good method of separation if you want to keep both the salt and the water. Most gases are colourless and cannot be seen. Activity: What happens when we throw things away? Run a magnet bar over the surface. The pigments in the ink are carried along by the liquid, but because they are different compounds, they get carried upward at different speeds. For example, imagine that our drinking water comes from a well in the ground and it is muddy. Waste disposal should be managed in a responsible way so that the negative impact on the environment is as small as possible. Is it possible to mix water? [2 marks],,,,,,,,,,,,, Always have clean water nearby to rinse your eyes or wash your hands if chemicals do splash or spill. Distillation is also the best way to separate two liquids that have different boiling points, like water and ethanol for example. 6, so learners should already be familiar with these concepts. Discuss the fact that scientists often need to handle dangerous substances and/or equipment to be able to make observations.