Unit 3 Preparing and Separating Mixtures

Unit 3

Preparing and Separating Mixtures Table of Contents

Introduction 3

Essential Questions 4

Review 4

Lesson 3.1: Preparing Mixtures 5

Objectives Warm-up Learn about It Key Points Web Links Check Your Understanding Challenge Yourself

5 5 6

12 12 13 14

Lesson 3.2: Methods of Separating Homogeneous Mixtures 16


16 16 17 20 20 21 23

Lesson 3.3: Methods of Separating Heterogeneous Mixtures 24


24 24 25 30 30 31 32

Lesson 3.4: Applications of Separating Mixtures 33

Objective Warm-up Learn about It Key Points Web Links Check Your Understanding Challenge Yourself

33 33 34 36 36 37 38

Laboratory Activity 39

Performance Task 41

Self Check 42

Key Words 43

Wrap up 44

Photo Credits 44

References 45

Copyright © 2018 Quipper Limited 2

Most of us are routinely performing preparation and separation of mixtures in our daily life without noticing it. When we prepare our favorite powdered breakfast drink or when we mix ingredients when baking or cooking, we are preparing mixtures. When we filter coffee from coffee grind or pick our favorite jelly bean flavor or color, we are separating mixtures. The process of obtaining salt from seawater is also a separation method. There are various ways to prepare mixtures that are useful for our daily living. Components of such mixtures may be separated manually. Separating techniques for mixtures depend on the composition of the mixture. These techniques take advantage of the differences in physical and chemical properties of substances in a mixture. Familiarizing with the common separation techniques for mixtures will give you an appreciation for the importance of these methods to our daily lives.


● What are the different methods in which we can prepare different kind of mixtures?

● How are homogeneous mixtures separated, as in the case of obtaining salt from seawater?

● How are heterogeneous mixtures separated, as in the case of coffee from the coffee grind?

● What are the different industrial processes that utilizes different separation procedures?

● Mixtures consist of two or more substances that are physically combined, thus, no chemical reaction is involved in its formation.

● There are two kinds of mixtures depending on the uniformity of its appearance after its components are combined together.

○ Homogeneous mixtures are mixtures that are uniform in appearance and composition. Each component in the mixture is spread evenly throughout the mixture.

■ A solution is an example of a homogeneous mixture. It is composed of solute, which is the substance that is being dissolved, and a solvent, which is the dissolving medium.

○ Heterogeneous mixtures are mixtures that are nonuniform in appearance and composition. Each component in the mixture can be distinguished and is not spread evenly throughout the mixture.

■ A suspension is a mixture that is has suspended particles which settle eventually.

■ A colloid is a heterogeneous mixture that is composed of two different phases in which particles of one substance is dispersed or distributed to another substance.


Almost all of the products you encounter and use every day are mixtures. Take for example the things that you see on a breakfast table. Coffee is an example of a solution and milk is a colloid. The cereals that you eat is an example of a heterogeneous mixture. Even the vitamins you take in the morning after eating breakfast is a mixture. These mixtures are composed of different substances combined together to form useful products. How are mixtures prepared?

Mix It Up Materials:

● sugar cubes ● powder sugar ● water ● detergent

● oil ● clear glass ● thermometer ● hot plate or stove

Procedure: A. Dissolving Sugar Cubes

1. Fill three fourths of the glass with water. Add one cube of sugar. Stir thoroughly.

2. Crush the sugar cube into smaller pieces. Repeat step 1 but use the crushed sugar instead. Observe.

3. Warm the water to around 50 to 60℃. Repeat step 1 but use warm water instead. Observe.


B. Playing with Food Dyes and Oil 1. Add a pinch of food coloring. Observe. 2. Add equal amount of oil to the resulting solution. Observe. 3. Add approximately 20 drops of liquid detergent. Observe.

Guide Questions:

1. Which method in part A dissolved the sugar faster and better? 2. What happened after adding the food coloring to water in part B? 3. What happened after adding the oil in step 2 of part B? 4. What happened after adding detergent in step 3 of part B?

Preparation of Solid-Solid Mixtures When solid substances are mechanically mixed together, a solid-solid mixture is formed. This mixture may be homogeneous or heterogeneous, depending on the visibility of each component. Solid-solid mixtures are often formed when preparing medicines and food. Herbs that are used for cooking are sometimes mixed together to form a more flavorful ingredient. Since these solid substances do not necessarily dissolve in one another, physical processes like tumbling and crushing, are used to ensure that the components are evenly distributed. As a result, a heterogeneous mixture of herbs is formed. This is also how medicinal leaves are prepared before boiling them to get their extracts.

Fig. 1. A heterogeneous mixture of herbs.


Another example of preparation of a solid heterogeneous mixture is 3-in-1 instant coffee mix. In this solid heterogeneous mixture, coffee powder, sugar, and creamer powder, are pre-measured and mixed together evenly. Each component differs in shape, size, and especially color. The mixture is then packaged into sachets and is ready for consumption. Variants from black coffee to white coffee are available in the market. Some solids, when mixed together form homogeneous mixtures. This is especially true when the appearance of each component is similar in size, color and texture. A good example for this is when you mix the dry ingredients in making a bread dough. Flour, baking powder, and a pinch of salt form a uniform appearance when mixed. When water and eggs are added into it, it will form a soft solid dough which is heated in an oven to bake it.

bread dough medicine

Fig. 3. Bread dough and medicines are examples of homogeneous mixture. Medicines in the form of tablets are also solid homogeneous mixtures. The solid components of this mixture are the active ingredient, solid fillers, and binders. These solid components are crushed to even particle sizes and then tumbled together to mix evenly. Afterwards, they are compacted to the shape of a tablet and packed individually. Some solid homogeneous mixtures are prepared by melting the components first before mixing them together. Melting is the application of heat to a solid, so it changes to a liquid above a temperature called the melting point. Upon cooling, the solid solution is made.


Melting is a technique used in creating alloys or homogeneous mixtures of metals. Gold jewelries are alloys made of steel and gold that are melted together. Cooking utensils, metal casings, and some electronic parts are made of alloys too. Melting is also used in mixing waxes together to form products like furniture wax.

Fig. 4. A ring made of steel and gold melted together.

Preparation of Liquid-Liquid Mixtures Liquid-liquid mixtures are also important in preparing food, drinks, and medicines. Liquid mixtures are prepared by mixing two different liquid components.

Homogeneous liquid mixtures form liquid solutions. Aqueous solutions are solutions where water is used as a solvent. Heterogeneous liquid mixtures, however, form colloids specifically called emulsions. To prepare a liquid-liquid solution, a liquid solute is simply added to a liquid solvent. An example of a homogeneous liquid-liquid solution is the preparation of alcohol disinfectants. Liquid ethyl alcohol or isopropyl alcohol is first acquired as a high concentration mixture. Concentration refers to the amount of solute dissolved in a certain amount of solvent. The most commercially available form of ethyl alcohol with high purity is 95% ethyl alcohol. To produce a 70% solution that is usually found in pharmacies and supermarkets, liquid water is added and mixed as a solvent, to dilute the ethyl alcohol to the right concentration. Dilution is the addition of water, or other solvents, to reduce the concentration of a solution.


To prepare a heterogeneous liquid-liquid mixture, or an emulsion, the components should not form a solution when mixed together. Emulsions rely on stabilizing agents, also called emulsifiers, so that they can mix together to form a colloid. For example, oil and water are immiscible, meaning they do not mix together. When soap is added to the oil and water mixture, it acts as emulsifier and forms a colloid.

Fig. 6. Oil and water mixes with soap as emulsifier.

Another example of an emulsion is mayonnaise, which is an emulsion made from oil, egg yolks and vinegar. Vinegar is primarily an acid dissolved in water. By mixing vigorously, oil is suspended in water from the egg yolk and vinegar solution. The proteins found in egg yolk acts as the emulsifier that prevents the separation of water and oil. Thus, it allows the colloid to form. Like mayonnaise, ketchup and mustard are also emulsions.

Fig. 7. Examples of condiments that are colloids.

Preparation of Solid-Liquid Mixtures To prepare a solid-liquid mixture, mix solid components with the liquids. Homogeneous solid-liquid mixtures form solutions while nonuniform solid-liquid mixtures form suspensions and colloids.


Solid-liquid solutions are prepared by dissolving a solid solute into a liquid solvent. Many solutions of this type exist in everyday life. For example, when powdered chocolate drink is dissolved in water and stirred. Stirring increases the speed at which a solute dissolves in a solvent.

chocolate drink hot tea

Fig. 8. Powdered chocolate drink and hot tea are examples of solutions. Solid-liquid solutions are also formed through boiling or heating. Heating involves raising of the temperature of the solvent to be able to extract the components of the solute. For example, when preparing herbal medicines, like lagundi, the leaves are boiled so that its components are extracted and dissolved in the heated solvent. Heating the solvent, allows the solute to be better dissolved in it. Another example of this when you prepare brewed coffee or tea. Crushing, or reducing the particle size of a solid solute, will also help increase the rate of dissolving of solids in liquids. A smaller particle size will enable the solute to come into contact more often with solvent particles, making it easier for them to dissolve. Crushing the medicinal leaves and boiling them with a hot solvent, will speed up the preparation of herbal medicines.

Fig. 9. Crushing leaves to reduce the particle size.


Heterogeneous solid-liquid mixtures are formed when the solid is naturally insoluble in the liquid and yet they are mixed together. These heterogeneous mixtures either form a suspension or a colloid. In a suspension, components separate over time and two phases. On the other hand, insoluble solids are simply suspended in the dispersing medium in a colloid. Preparing colloids requires solid particle sizes to be small enough to be dispersed, and stabilizing agents to prevent separation. An example of a solid-liquid suspension is sand underneath the sea. The sand does not get dissolved in the water. When agitated, sand briefly suspends in the water then settles down over time. Forming these suspensions is very useful in applications like water treatment. In water treatment, an insoluble solid like activated charcoal is allowed to suspend in polluted water. The pollutants in water stick to the activated charcoal, so that when separation occurs, the water becomes free of the pollutants and can be safely reused.

An example of a solid-liquid colloid, or liquid sol, is paint. In paint, solid insoluble pigments are crushed and suspended in the liquid medium of the paint (often water). In addition, suspended pigments are better able to protect surfaces from UV radiation damage, because they make the mixture cloudy because of the Tyndall effect. The Tyndall effect is a characteristic of colloids. Light scatters as it hits the particles suspended in colloids.

Fig. 10. Paint is an example of a colloid.


● Different mixtures can be prepared depending on the use. Some ways to prepare solutions are stirring, heating, crushing, melting and emulsifying.

● There are three different types of mixtures based on their components: solid-solid mixtures, liquid-liquid mixtures, and solid-liquid mixtures.

● Each type of mixture can be homogeneous or heterogeneous mixture, depending on the property of each material being mixed.

● Alloys are homogeneous mixtures of metals, which are usually prepared by melting.

● Most liquid-liquid mixtures are aqueous in nature. Aqueous solution uses water as solvent. An aqueous solution is concentrated if a large amount of solute is dissolved in the solvent, while an aqueous solution is diluted if a small amount of solute is dissolved in the solvent.

● Heterogeneous liquid-liquid mixtures, also known as emulsions, contain two liquids that are immiscible to one another. Emulsifiers are added to keep the liquids mix each other.

● Heterogeneous solid-liquid mixtures are either suspension or colloids. ○ In suspensions, components separate over time and two phases. ○ In colloids, solid particle sizes are small enough that it gets dispersed.

For further information, you can check the following web links:

● See how passing a light through a mixture may help in determining whether it’s heterogeneous or homogeneous. Tommy Technitium. 2017. Heterogeneous and Homogeneous Mixtures. VIdeo. https://www.youtube.com/watch?v=54mB2--vFDg

● How does a heterogeneous and homogeneous mixture look like on a molecular level? ChemPrime. 2010. ‘Solutions.’ Web. http://wiki.chemprime.chemeddl.org/articles/s/o/l/CoreChem~Solutions_7a78.html


https://www.youtube.com/watch?v=54mB2--vFDg

https://www.youtube.com/watch?v=54mB2--vFDg

http://wiki.chemprime.chemeddl.org/articles/s/o/l/CoreChem~Solutions_7a78.html

http://wiki.chemprime.chemeddl.org/articles/s/o/l/CoreChem~Solutions_7a78.html

A. Identify the following statements as true or false. 1. Increasing the temperature increases the rate of dissolution of solids in

liquids. 2. Tyndall effect is the ability of homogeneous mixtures to scatter light. 3. Preparing mixtures by agitation only works for solid-liquid mixture. 4. Immiscible liquids are liquids that do not mix and forms two layers. 5. Activated charcoal do not dissolve in water and therefore is heterogeneous. 6. Alloys are prepared by melting the metals before mixing. 7. Emulsifiers help in separating the components of a colloid. 8. Crushing helps in preparing liquid-liquid mixtures. 9. Colloid particles are big enough to settle at the bottom of a mixture.

10. Dilution is the amount of solute that is soluble in a particular solvent.

B. Describe the preparation of the following mixtures.

1.

2.

3.

4.


5.

6.

7.

8.

9.

10.

Answer the following.

1. Certain medicine may be prepared by dissolving the medicine in a certain amount of water. Discuss the importance of the knowledge in mixtures during medicine preparation.

2. There are several ways of expressing concentration, and one of them is weight percentage, defined as the mass of solute (in grams) per 100 grams of solution. Vinegar contains approximately 5% acetic acid by weight. Discuss


this concentration in terms of mass of solute and mass of solution. 3. Give an outline on the classification of matter and highlight where

homogeneous and heterogeneous mixtures are located. 4. In the preparation of iced coffee, it is important to dissolve the coffee in

small amount of hot water first. Discuss the importance of this step. 5. When preparing orange juice from juice mix, hot water is not used. Why?


One unique characteristic of a homogeneous mixture is its uniform appearance since its components are uniformly distributed all throughout. Just by merely looking at it, one might think that it is “pure” in terms of its composition. However, this kind of mixture can be separated into its simpler substances. Since this mixture is prepared without any chemical reaction, its components can be separated through physical means. What are some ways to separate homogeneous mixtures?

Separating Homogeneous MIxtures Materials:

● water ● salt ● soda

● measuring cup ● cooking pot ● stove

Procedure: A. Separating Salt and Water

1. Weigh around 18 grams of table salt in a beaker and dissolve it in 50 mL of water. Stir the solution thoroughly. Make sure that all the solids get dissolve in water.

2. Transfer 20 mL of the resulting mixture in another container. 3. Heat the mixture to dryness and observe what appears in the container.

.


B. Separating Water from Soda 1. Freeze a bottle of soda in a refrigerator. You can already freeze the soda

prior to this activity. 2. Partially thaw the soda to the point that you can see ice chunks that are

relatively clear. 3. Separate the ice from the rest of the liquid. 4. Completely thaw the ice. Let it melt and observe the color of the resulting

liquid. 5. Compare the color of the melted ice to the liquid that was separated earlier.

Is there any significant difference? Guide Questions:

1. What is left after evaporating water in part A? 2. How will you describe the material produced in part A of this activity?

Describe its properties in detail. 3. List down the differences in the two liquids separated in part B. What do you

think are the identities of these liquids?

Separating Solid-Liquid Mixtures Evaporation Evaporation is the process of turning liquids into vapor (gas) by heating. In this process, a solid-liquid solution is heated until it boils. Once the solution boils, the liquid solvent starts to evaporate and leave behind solid solutes. The case for solid solvents and liquid solutes separation can also take advantage of evaporation. This method is often used to separate salts from seawater.


Recrystallization Recrystallization is done by cooling down a solution to lower the solubility of the solute components until crystals are formed. Solubility refers to the ability of a substance to be dissolved in a given solvent at a certain temperature. Recrystallization is often applied to purify solid components in a solution. For example, to purify molasses, a mixture of molasses and sea water is set aside until it cools down. Also, take note that the colder the solvent, the lower the solubility of a solute. Therefore, more solute recrystallizes out of the solution. This is how brown sugar is extracted from molasses. Separation of Liquid-liquid Mixtures Distillation Distillation is a separation technique for homogeneous liquid mixtures. It makes use of the difference in boiling points between two liquids. In order for the technique to work, the components should have a large enough difference in boiling points, so that when one component boils, the other remains as a liquid. The boiling liquid vapor is then condensed and collected into another container to separate the two components. The illustration below shows a distillation set-up separating acetone and water.

Fig. 12. A distillation setup.

A distilling flask is a laboratory glassware that is used to contain the mixture that will be distilled. In the acetone and water solution, acetone has lower boiling point (560C) compared to water (1000C). When the solution is boiled, the acetone vapor boils and evaporates first, leaving the water in the flask. The acetone vapor cannot escape since the flask is connected to a condenser, a glassware that aids


condensation or change of vapors (gases) to liquids. Since cold water gets in the condenser, the acetone vapor cools down until it turns to liquid again. The acetone will then be collected to the other container, fully separated from water. The collected pure acetone is known as the distillate or the product of distillation. This process is often used to separate crude oil to different fuels like gasoline, kerosene, and lubricating oil. Chromatography Another way to separate liquid-liquid mixtures is through chromatography. It is a separation technique that relies heavily on the differences in solubility of each solute in a solvent. The two important phases in chromatography are the mobile phase, which is the solvent and the stationary phase, which is an absorbent material that holds the liquid solution still. Since the stationary phase is an absorbent material, it allows the mobile phase to pass through it and travel along. As the mobile phase runs through the stationary phase, the components of the liquid solution separate based on their solubility in the given solvent. Liquid solutes that have high solubility in the mobile phase will go along with the mobile phase as it travels on the stationary phase. On the other hand, liquid solutes that have low solubility will tend to remain where they are. Below is an illustration of a paper chromatography set-up, which makes use of paper as the stationary phase, and a solvent (water) as the mobile phase.

Fig. 13. A paper chromatography setup.


In paper chromatography, the mobile phase runs through the paper upwards, the components of the ink solution separate into its component dyes. The result of a chromatography experiment is called a chromatogram, which is a visual record of the result. One can see, from the illustration, that the yellow dye component in black ink has the highest solubility in the mobile phase, while purple dye component has the least solubility among the ink’s dye components.

● Homogeneous solid-liquid mixtures may be separated using evaporation and crystallization.

○ Evaporation is the process of turning liquids into vapor (gas) by heating. It is used to dry up water and crystallize the substance of interest.

● Homogeneous liquid-liquid mixtures may be separated using distillation and chromatography..

● Distillation is a separation technique for homogeneous liquid mixtures. It makes use of the difference in boiling points between two liquids.

○ A distillation setup contains a distilling flask to hold the sample, a condenser to prevent the sample from evaporating and clamps for securing the materials in an iron stand.

○ Chromatography is a separation technique that relies heavily on the differences in solubility of each solute in a solvent.

○ Chromatography has two important phases: the mobile phase, which is the solvent and the stationary phase, which is an absorbent material that holds the liquid solution still.



● Check this simulation of the distillation process. Edumedia. 2018. ‘Distillation.’ VIdeo. https://www.edumedia-sciences.com/en/media/487-distillation

● Watch how pigments of leaves can be separated using paper chromatography. Nhoxkorocute. 2013. Chlorophyll Chromatography. Video. https://www.youtube.com/watch?v=jiPd5CkCkkU

A. Identify the words being described in each statement.

1. It is the data obtained from a chromatography experiment. 2. It is the solvent used in chromatography. 3. It is the collected pure substance after distillation. 4. It is the ability of a substance to dissolve another substance which is the

basis for recrystallization. 5. It pertains to the adsorbent material that holds the solvent in

chromatography. 6. It is the apparatus used in distillation.

B. Match the techniques in column A and the descriptions in column B.

Column A Column B

1. evaporation 2. distillation 3. recrystallization

a. Involves a mobile phase and a stationary phase.

b. Involves the separation of a solid solute


https://www.edumedia-sciences.com/en/media/487-distillation

https://www.edumedia-sciences.com/en/media/487-distillation

https://www.youtube.com/watch?v=jiPd5CkCkkU

https://www.youtube.com/watch?v=jiPd5CkCkkU

4. paper chromatography

from a liquid solvent c. A method where the difference in boiling

point is used to separate the components. d. A method where the difference in melting

point is used to separate the components.

C. How would you separate the components of the following homogeneous

mixtures?

1.

instant coffee drink

2.

honey

3.

perfume

4.

cartridge ink

5.

alcoholic beverages

6.

highlighter ink


7.

saltwater

8.

plant pigments

9.

crude oil

10.

vinegar

Answer the following questions.

1. Outline the separation of mixture of sodium chloride, water, and alcohol. 2. Plant pigments are usually separated using chromatography. Is distillation

possible in separating plant pigments? Why? 3. Chromatography utilizes the difference in solubility of the components of a

mixture. Substance X is found to go with the mobile phase which is water. What would happen if the solvent was replaced with gasoline?

4. Nail polish remover is a mixture of acetone and water. At sea level, the boiling point of water is 100℃ and that of acetone is 56℃. Which will distill first, acetone or water? Which will be the distillate? Explain your answer.

5. Medicinal components in plants may be separated using chromatography. Outline a reason why evaporation or distillation is not employed in separating plant components.


Unlike solutions, heterogeneous mixtures have components that are visible which makes it easier to identify them. This is the reason why heterogeneous mixtures may be separated manually. What are the techniques to separate heterogeneous mixtures?

Separating Oil and Water Materials:

● cooking oil ● water ● food coloring ● nail ● medicine dropper ● containers or beakers ● empty soda bottle with plastic cap

Procedure: A. Separating Oil and Water by Decantation

1. Fill half of a container with water. Then, using the medicine dropper, add three to five drops of food coloring to the water.

2. Add oil with a volume equivalent to that of the water in the beaker. 3. Observe the resulting mixture. Then, tilt the container to remove the oil

which is on top of the water. Collect the oil in another container.


B. Separating Oil and Water Using an Improvised Separatory Funnel 1. In a soda bottle, mix an equivalent amount of oil and water. 2. Place a hole in the cap of the bottle using a nail. 3. Cover the bottle with the cap. 4. Invert the bottle. Let the water drip until only the oil is left. Collect the water

in another container. C. Separating Oil and Water by Freezing

1. In a bottle, mix an equivalent amount of oil and water. 2. Place the bottle in a freezer until the oil freezes or solidifies. 3. Remove the water from the mixture while the oil is still solid by tilting the

container. Collect the water in another container. Guide Questions:

1. How can you describe the mixture of oil and water? Is it heterogeneous or homogeneous? Is it a solid-solid, a liquid-liquid or a liquid-solid mixture?

2. Which is more dense, water or oil? Why? 3. Which method separated oil and water faster? 4. In which method were the oil and water completely separated? 5. Which method do you think is the most efficient and effective in separating

oil and water?

Separating Heterogeneous Mixtures Heterogeneous mixtures with big, visible components may be separated into simpler substances through manual picking. Using hands or tongs, components of this kind of mixture may be separated into various containers by picking them individually. This is usually done to separate different non-biodegradables in a trash bin. In some provinces, not all farmers have machineries to separate rice grains from husks. Instead, they separate the hard covering of rice grains through winnowing. In this method, the rice grains with husks are placed into a bilao or any flat pan. The mixture is thrown up in the air over and over again. The pan is used to catch the rice grains as they fall down. During the process, the husks are separated from the rice grains as the wind blows.


Fig. 14. Farmers separate rice grains from husks by winnowing.

Separation by sieving takes advantage of the difference in particle size of solids. A sieve is a layer of holes that allow only certain sizes of particles to pass. An everyday example of a sieve is a kitchen sifter which is used for separating large clumps from fine flour particles. This technique is also applicable in separating sand from gravel before preparing a cement mixture.

Fig. 15. A kitchen sifter used to separate clumps of flour.

Some heterogeneous mixtures contain metallic components. These metallic components may be separated from the mixture by using a magnet. Iron, and other metals like nickel and cobalt are attracted to magnets. An example of mixture that may be separated using a magnet is iron filings and sulfur. When a magnet is placed near the mixture, the iron filings will be attracted to it which will cause its separation from the sulfur.


Fig. 16. Iron filings attracted to a magnet and separating from sulfur powder.

Solid-liquid suspensions and colloids require more tedious techniques to be able to separate their components. Filtration is a process of separating solids from liquids by allowing the mixture to pass through a filtering material. Filters can be used to separate suspended solids from liquids. This is provided that the filter paper used has holes small enough for suspended solids not to pass through. A common example of filtration is when you separate coffee grounds from brewed coffee. The coffee grounds are separated from the brewed coffee because its particles are too big to pass through the holes of the coffee filter. The coffee grounds collected on the filter paper is known as the residue while the brewed coffee is known as the filtrate.

Fig. 17. Coffee grounds separated using a filter paper.


Sedimentation is the process in which suspended solids will eventually separate from liquids by gravity. Once the solid particles settle at the bottom, the liquid may be separated through decantation. Decantation is the removal of the liquid component from a solid sediment by pouring the liquid out of the container gently to avoid the solid particles to suspend again. It can be pumped out also using a syringe or other suctioning device. Decantation may be aided with the use of a stirring rod to direct the flow of the solvent and prevent splashing.

Fig. 18. Decantation using a stirring rod.

Decantation may also be used to separate mixtures with liquids that are immiscible or do not mix well. An example of this is a mixture of oil and water. Since the water settles at the bottom, slowly pour out the oil from the container to separate it from water. An easier way to separate oil from water is by using a separatory funnel. It is a glassware used to separate two liquids with different densities.

Fig. 19. Using a separatory funnel to separate oil and water.


Solid-liquid suspensions can undergo centrifugation, a process in which the suspension is rotated at very high speeds. Centrifugation uses a machine called a centrifuge that rotates the sample. The centrifugal force pushes down the solids, which will accumulate at the bottom of the container. The liquid can then be decanted to separate the solid from the liquid.

Fig. 20. A centrifuge machine.

Blood is a common example of mixture in which centrifugation is used to separate its components. Take for example the illustration below, the solid particles are dispersed in the mixture. But after centrifugation, the solid particles are separated from the liquid as they settle at the bottom. Even different liquids with different densities separate into layers. The layers can be separated from one another. Specific blood tests can be administered to each of those layers, telling something about the person’s blood in general.

Fig. 21. Particles of a mixture before and after centrifugation.


● DIfferent methods can be used to separate heterogeneous solid-solid mixtures. Components of some mixtures of this type can be separated by manual picking, sieving or by using a magnet.

● DIfferent methods can be used to separate heterogeneous solid-liquid mixtures. Some of these are discussed briefly below.

○ Filtration is a process of separating solids from liquids by allowing the mixture to pass through a filtering material.

○ Sedimentation is the process in which suspended solids will eventually separate from liquids by gravity.

○ Decantation is the removal of the liquid component from a solid sediment by pouring the liquid out of the container gently to avoid the solid particles to suspend again.

○ Centrifugation is a process in which the suspension is rotated at very high speeds, allowing the components to separate into layers based on their densities.

● A separatory funnel can be used to separate heterogeneous liquid-liquid mixtures.


● Watch how a centrifuge separates components of mixtures. KClassScienceChannel.2013. Centrifugation|Separation Methods| Physics. VIdeo https://www.youtube.com/watch?v=KEXWd3_fM94

● Watch how a magnet is used in separating recyclables. Conveyortek. 2012. Overband Conveyor Magnet for the Recycling Industry. Video. https://www.youtube.com/watch?v=nvJFFIzAwqI


https://www.youtube.com/watch?v=KEXWd3_fM94

https://www.youtube.com/watch?v=KEXWd3_fM94

https://www.youtube.com/watch?v=xUX-nmPL9SE

https://www.youtube.com/watch?v=nvJFFIzAwqI

A. Match the separation technique in column A to the description in column B.

Column A Column B

1. Manual picking 2. Winnowing 3. Filtration 4. Decantation 5. Sieving 6. Use of magnet 7. Centrifugation

a. Use of a high speed rotating machine to separate components.

b. Separation by tilting the container and removing the liquid on top.

c. Separate metals from other materials. d. Separate solid mixtures with different

sizes. e. Separate grains from the husk f. Separate components using the hands or

tongs. g. Separation of liquid and solid by passing

the mixture through a filtering material

B. Write Yes if the separating technique is appropriate for the given mixture. If not,

identify what separation technique is applicable to separate the components of the mixture.

1. colored clothes from white clothes = winnowing 2. chalk and water = filtration 3. staple wires and sand = using a sieve 4. rock salt and cornstarch = winnowing 5. rice grains and water = sedimentation and decantation 6. urine components = centrifugation 7. boiled noodles in water = filtration 8. sand and gravel = decantation 9. baby oil and water = evaporation

10. pineapple chunks from pizza = manual picking 11. picking greens in salad = 12. separating of cheese from milk using a cheesecloth = decantation 13. blood and blood plasma = centrifugation



1. A traditional way of extracting gold is by panning. What is the closest separation discussed is closest to panning? Cite differences and similarity between your answer and panning.

Gold panning

2. What is the key differences between decantation and filtration. 3. A bunch of needles fell on a basket of feathers. What is the best method to

use to separate the needles from the feathers without hurting yourself? 4. You saw a large bottle of a mixture with the following components: water,

sand, soil, and salt. What techniques will you use to separate all the components of the mixture? Which technique will you do first? Which method will you do last?

5. Why is centrifugation not used in preparing drinks such as tea and coffee?


There are many mixtures that you encounter daily. These mixtures have many uses not only at home but also in different industries. This is the reason why there is a continuous preparation of mixtures to address the needs of many. Separating the components of mixtures is equally important as preparing them. What are some important applications of mixture separations?

Improvised Water Filtration System Materials:

● plastic bottle ● sand ● gravel ● activated charcoal ● cotton ● muddy water

Procedure:

1. Cut the bottom of the plastic bottle. 2. Turn the bottle upside down. Place

cotton on the mouth of the bottle. 3. Add activated charcoal, fine sand, and

gravel as shown in the illustration. 4. Add muddy water on the open side of

the bottle.


5. Collect the the water that comes out from the bottom

Safety Precaution Do not drink the water coming out from the filtration system! The water should be subjected to tests first to find out how efficient is our improvised water filtration system.

Guide Questions:

1. Compare the water before and after passing it through the improvised water filtration system.

2. Identify the components of the filtration system that helped in improving the quality of water. Describe what does each part do to achieve a filtered potable water.

3. How important is a water filtration system? Suggest ways on how this little machine can make a great difference in the country in the near future.

Separation techniques find great use in a variety of different industries. In the chemical and pharmaceutical industry, separation techniques are used to purify chemicals to acceptable standards. For example, in order for a medicine to be acceptable for use, it has to be purified to remove extremely toxic chemicals that were used to manufacture it. Medicines like paracetamol or aspirin, are recrystallized from solution to bring it to acceptable standards.


Fig. 22. Recrystallized aspirin tablets. A refinery is an industrial site that is used to refine substances like oil, alcohol, and other substances. In this place, distillation is often used as a method to purify products. In the petroleum industry, crude oil is distilled to gasoline, kerosene and other petroleum products in order to be acceptable for applications. Petroleum products are used as fuel which is essential to production of many other products and support a comfortable way of modern living. In the wastewater industry, separation techniques such as sedimentation, centrifugation, microfiltration, and distillation are used to recover water from used water. By doing so, harmful substances are removed before releasing the waste water to the environment. Household water treatment includes processing of tap water to separate water from contaminants, making it suitable for drinking. It may include separation methods such as filtration, sedimentation, and use of activated carbon. In this way, tap or faucet water becomes more suitable for drinking because of the removal of particulates, odor, color and even some harmful, less persistent bacteria. However, it is advisable to check the water quality first before drinking any treated water.


Fig. 24. A water filtration system. In the field of medicine, centrifugation is used to separate the components of blood or urine for further laboratory testing. In blood centrifugation, the blood extracted from the patient is placed in a centrifuge tube. This will be placed in a centrifuge for a few minutes until the components are completely separated. The liquid component of the blood will be filtered to separate the blood cells. Afterwards, the laboratory technician will be able to determine count of blood cells through a microscope. The result of this observation can tell whether the patient has infection. This is also how urine testing is done.

● Separating mixtures plays an important role in several industrial processes. ● Crude oil is distilled in a refinery to separate useful components such as

gasoline, kerosene, and diesel. ● Fresh water undergoes various treatment including filtration to obtain

potable water. These techniques include sedimentation, centrifugation, microfiltration, and distillation are used to treat faucet water and make it more potable.

● In the field of medicine, components of blood may be separated by centrifugation before analysis in a clinic or laboratory. These layers can be tested for specific target molecules the patient is looking and monitoring for.


● How does an oil refinery work? FuseSchool Global Education. 2013. Crude Oil Fractions and their uses. Video. https://www.youtube.com/watch?v=JZdvsQzOKuk


https://www.youtube.com/watch?v=JZdvsQzOKuk

https://www.youtube.com/watch?v=JZdvsQzOKuk

Travel through the different separation method wastewater have to go through when being treated. Water Environment Federation. 2012. Water Resource Recovery Facility 3D Virtual Tour. VIdeo. https://www.youtube.com/watch?v=A2FmNrEmowE

A. Name some of the techniques used in the following industrial processes. 1. desalinating sea water for consumption 2. extracting flavors from plant sources 3. extracting essential oil for perfumes 4. manufacturing artificial food colorants safe for consumption 5. counting blood cells in medical tests 6. purifying sugar from sugar cane 7. separating kerosene and gasoline from fossil fuels 8. separating different components of cells. 9. purification of drugs

10. removing metals from recyclables.

B. Identify whether the following statements are true or false. 1. Separation methods are important in the manufacturing of drug. 2. Wastewater is treated to make it suitable for drinking. 3. Refinery works by utilizing the different melting points of the components

of crude fossil fuel. 4. Blood components are separated using filtration. 5. A filtration system improves the quality of freshwater, making it more

suitable for drinking. 6. Urine samples are subjected to filtration before analysis. 7. Distillation of seawater is a common water treatment practice. 8. Treating sewage water removes impurities that may harm the

environment. 9. Recrystallization separates a drug from impurities.

10. Centrifugation is the primary separation method in a refinery.


https://www.youtube.com/watch?v=A2FmNrEmowE

https://www.youtube.com/watch?v=A2FmNrEmowE


1. Medicines are primarily used to make a sick person feel better. Discuss the significance of purifying medicine before use.

2. An oil refinery separates the components of crude fossil fuel. How does a refinery helps various industry that are dependent on fossil fuel?

3. Aside from the usual water treatment done in large facilities, certain household would opt to have a separate water filtration system. Discuss why is this setup important.

4. Why is evaporation and distillation not suitable in water treatment? 5. Chromatography is useful in visualizing the separation of components of

certain inks and pigments. However, it is difficult to recover the separated components. Discuss the other importance of paper chromatography.


Activity 3.1 Separating Ink Components Using Chromatography

One method of separating mixture is through chromatography. It separates components of a mixture based on the solubility of a component in a moving solvent called the mobile phase. In this experiment, the components of ink will be separated using paper chromatography. Objective At the end of this laboratory activity, the students should be able to:

● separate the different components of whiteboard marker using paper chromatography.

Materials and Equipment

● water ● rubbing alcohol ● isopropyl alcohol ● vinegar ● whiteboard marker ● filter paper ● used glass jar

Procedure

1. Prepare a filter paper with the dimensions of 10 cm by 4 cm. 2. Draw a line 1 cm from the side of the length of the paper. 3. On the other side, draw a line using the whiteboard marker 1 cm from the

side. 4. Add water inside the jar, around 0.5 cm from the bottom. 5. Place the paper inside the jar, with whiteboard marker line at the bottom.

Make sure that the water will not touch the line! 6. Let the water go up the paper until the water level reaches the pencil drawn

line on the other side. 7. Repeat the steps 1 to 6 using vinegar and alcohol instead of water.


Waste Disposal 1. Dispose filter paper in “recyclables” or “paper” bin. 2. Flush excess water, rubbing alcohol, and vinegar in the sink.

Observation Draw the paper chromatogram for each of the setup. The paper chromatogram is the resulting filter paper after doing the whole experiment. Make sure to reflect the exact positions of the spots you have in your chromatograms.

Guide Questions

1. Why should the marker line remain unwet before chromatography starts? 2. For each set-ups, identify the stationary and mobile phase(s) used in the

experiment. 3. How many colors do you see for each of the set-ups? 4. In which set up were the colors better separated?


Mixtures Unmixed

Goal: The goal of this task is to demonstrate knowledge on mixture

separation. Role: You are an alchemist who wants to separate the components of the

mixture prepared by his rival after finding out the dangers of all theses mixtures.

Audience: Your audience are alchemists who has no knowledge on mixture

separation. Situation: The rival alchemist prepared several mixtures that were found as a

threat to all living things. You gather other alchemists to avert any catastrophe that may result from this by finding out how to separate these mixtures.

Product, Performance, and Purpose: You are tasked to prepare a scrapbook of all the separation procedure, complete with illustration and example. This book will be given to other alchemist for them to study.

Standards and Criteria Your performance will be graded by the following rubric.

Criteria Below

Expectations, 0% to 49%

Needs Improvement

50% to 74%

Successful Performance 75% to 99%

Exemplary Performance

100%

Separating Homogeneous mixtures

No separation method about homogeneous mixtures were discussed.

Methods of separating homogeneous mixtures were discussed but some were not

All the methods of separating homogeneous mixtures were discussed accurately Minor

All the methods of separating homogeneous mixtures were discussed accurately and


accurate or incomplete. There are certain discussion not related to the topic.

details were missing and small improvements can be made.

completely.

Presentation No scrapbook were made.

No illustration about separation of mixtures were made.

Illustrations were made. minor improvements can be made.

Illustrations about separating mixtures were made. The presentation was clear and organized.

After learning about preparation and separation of mixtures, can you now dp the following?

Check I can…

differentiate the different method mixtures are prepared.

enumerate how homogeneous mixtures are separated.

identify the different methods to separate heterogeneous mixtures.

know the importance of separating mixtures in the preparation of various everyday materials.


Centrifugation It is a separation method where the mixture is rotated at

high speed.

Chromatography It is a separation technique based on the solubility of the components in the mobile phase and stationary phase.

Concentration It is the amount of solute dissolved in a certain amount of solvent.

Decantation It is a separation technique where the liquid component of a sediment is removed.

Dilution It is a mixture preparation technique where solvent is added to a solution to reduce the concentration.

Distillate It is the product of distillation.

Distillation It is a method of separating homogeneous liquid solution with different boiling points.

Emulsifier It is a stabilizing agent added to mixtures to form an emulsion.

Filtrate It refers to the separated liquid component after filtration.

Filtration It is a process of separating a solid liquid solution by passing the mixture in a filtration medium.

Immiscible It is used to describe two liquids that are not soluble and forms two layers when mixed together.

Refinery It is a facility that separates the component of fossil fuel by fractional distillation.

Residue It is the separated solid component after filtration.

Winnowing It is a method that separate rice grain from husks.


Preparation and Separating Mixtures

Introduction Picture. JellyBellyBeans by Brandon Dilbeck is licensed under CC

BY-SA 3.0 via English Wikipedia. Fig 26. Milli-Q Water Filtration Station by Proaudio55 is licensed under CC BY-SA

3.0 via Wikimedia Commons.


https://commons.wikimedia.org/wiki/File:JellyBellyBeans.jpg

https://en.wikipedia.org/wiki/User:Brandon_Dilbeck

https://creativecommons.org/licenses/by-sa/3.0/legalcode

https://creativecommons.org/licenses/by-sa/3.0/legalcode

https://en.wikipedia.org/wiki/

https://commons.wikimedia.org/wiki/File:Milli-Q_Water_filtration_station.JPG

https://commons.wikimedia.org/w/index.php?title=User:Proaudio55&action=edit&redlink=1

https://creativecommons.org/licenses/by-sa/3.0/

https://creativecommons.org/licenses/by-sa/3.0/

https://commons.wikimedia.org/wiki/Main_Page

Amrita University. “Separation of Mixtures Using Different Techniques”. Accessed 08

May 2017. http://amrita.olabs.edu.in/?sub=73&brch=2&sim=96&cnt=1 Education Services Australia. “Mixing and Separating. Accessed 08 May 2017.

http://scienceweb.asta.edu.au/verve/_resources/asta_5-1-1_bi_mixing_yr7_v1_2.pdf

National Academies Press. “Chemical Industry”. Accessed 08 May 2017.

https://www.nap.edu/read/6388/chapter/4 Silberberg, Martin. 2009. Chemistry: The Molecular Nature of Matter and Change,

5th edition. Theodore L. Brown et al. 2015. Chemistry: the central science. Boston: Pearson.

Elmhurst College. “What are Mixtures and Solutions?”. Accessed May 2, 2017. http://chemistry.elmhurst.edu/vchembook/106Amixture.html

Deped BEAM Distance Learning Program. “Science and Health: Mixing Solids with

Solids”. Accessed May 20, 2017. https://drive.google.com/file/d/0B8DPX5vC83iscG4weUJIYmNmUXc/view

Deped BEAM Distance Learning Program. “Science and Health: Liquids with other

Liquids”. Accessed May 20, 2017. https://drive.google.com/file/d/0B8DPX5vC83isbDVUcTV4dm5DRGs/view

Veterans Regional Hospital, Department of Health, Republic of the Philippines.

“Health Guide”. Accessed May 20, 2017.


https://www.nap.edu/read/6388/chapter/4

http://chemistry.elmhurst.edu/vchembook/106Amixture.html

https://drive.google.com/file/d/0B8DPX5vC83iscG4weUJIYmNmUXc/view

https://drive.google.com/file/d/0B8DPX5vC83isbDVUcTV4dm5DRGs/view

https://drive.google.com/file/d/0B8DPX5vC83isbDVUcTV4dm5DRGs/view

Unit 3 Preparing and Separating Mixtures

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Transcript of Unit 3 Preparing and Separating Mixtures