Mixtures and Their Separation Form II Science PDF

**Form II Science** =================== **Mixtures and their separation** ================================= {#section.BodyText} {#section-1.BodyText} {#section-2.BodyText} {#section-3.BodyText} Name: {#name.BodyText} ===== {#section-4.BodyText} Master {#master.BodyText} ====== {#secti...

**Form II Science** =================== **Mixtures and their separation** ================================= {#section.BodyText} {#section-1.BodyText} {#section-2.BodyText} {#section-3.BodyText} Name: {#name.BodyText} ===== {#section-4.BodyText} Master {#master.BodyText} ====== {#section-5.BodyText} {#section-6.BodyText} Filtration separating mixtures liquid filtration Vector Image **Outcomes:** +-----------------------------------+-----------------------------------+ | **OUTCOMES At the end of this | | | topic, pupils should be able | | | to:** | | +===================================+===================================+ | 1. 1 | **IDENTIFY** that pure substances | | | at standard temperature and | | | pressure have constant physical | | | properties e.g. melting point, | | | boiling point, magnetism, | | | density, solubility and colour | | | (often). | +-----------------------------------+-----------------------------------+ | 2. 2 | **DESCRIBE** pure substances as | | | consisting of either elements or | | | compounds, and mixtures as | | | consisting of more than one type | | | of element and/or compound. | +-----------------------------------+-----------------------------------+ | 3. 3 | **DESCRIBE** at a particle level | | | the difference between elements, | | | compounds and mixtures, including | | | the type and arrangement of | | | particles. | +-----------------------------------+-----------------------------------+ | 4. 4 | **SEPARATE** iron filings and | | | sucrose from a mixture of iron | | | and sucrose. | +-----------------------------------+-----------------------------------+ | 5. 5 | **GIVE** specific examples of | | | pure substances and mixtures. | +-----------------------------------+-----------------------------------+ | 6. 6 | **EXPLAIN** the difference | | | between a solution and a | | | suspension. | +-----------------------------------+-----------------------------------+ | 7. 7 | **DESCRIBE the importance of | | | water as a solvent in daily life, | | | industries and the environment.** | +-----------------------------------+-----------------------------------+ | 8. 8 | **DESCRIBE** aqueous mixtures | | | using the words solute, solvent | | | and solution. | +-----------------------------------+-----------------------------------+ | 9. 9 | **UNDERSTAND** the terms dilute, | | | concentrated and saturated | | | solutions. | +-----------------------------------+-----------------------------------+ | 10. | **SEPARATE** a suspension by the | | | process of filtration and | | | **IDENTIFY** situations when this | | | technique would be appropriate. | +-----------------------------------+-----------------------------------+ | 11. | **DEFINE** the terms filtrate and | | | residue. | +-----------------------------------+-----------------------------------+ | 12. | **SEPARATE** a solute from a | | | solution by evaporation and | | | crystallisation and **IDENTIFY** | | | situations when these techniques | | | would be appropriate. | +-----------------------------------+-----------------------------------+ | 13. | **RECALL chemical changes and | | | COMPARE physical and chemical | | | changes** in terms of the | | | arrangement of particles and | | | reversibility of the process. | +-----------------------------------+-----------------------------------+ | 14. | **IDENTIFY** that a physical | | | change has occurred in the | | | process of evaporation. No new | | | chemicals have been formed. | +-----------------------------------+-----------------------------------+ | 15. | **SEPARATE** a suspension by the | | | process of sedimentation, | | | decanting, sieving and | | | centrifuging and **IDENTIFY** | | | situations when these techniques | | | would be appropriate. | +-----------------------------------+-----------------------------------+ | 16. | **OBSERVE** the separation of an | | | appropriate mixture by simple | | | distillation and **DRAW** a | | | labelled diagram to represent the | | | process. **IDENTIFY** situations | | | in which this technique would be | | | appropriate. | +-----------------------------------+-----------------------------------+ | 17. | **DEVISE** an experiment to | | | separate a mixture of iron | | | filings, sand, salt and wood | | | shavings. | +-----------------------------------+-----------------------------------+ | 18. | **CONDUCT** an experiment to | | | demonstrate Chromatography. | +-----------------------------------+-----------------------------------+ | 19. | **JUSTIFY** methods of separating | | | mixtures using the physical | | | properties of the components and | | | the mixtures. | +-----------------------------------+-----------------------------------+ +-----------------------------------+-----------------------------------+ | **RESEARCH SKILLS: During this | | | topic this topic, you will:** | | | | | | **Non-examinable** | | +===================================+===================================+ | 20. | **RESEARCH** how people in | | | different occupations use | | | understanding and skills from | | | across the disciplines of Science | | | in carrying out separation | | | techniques. | +-----------------------------------+-----------------------------------+ | 21. 21. | **DESCRIBE**, using examples, how | | | science knowledge can develop | | | through collaboration and | | | connecting ideas across the | | | disciplines of science, e.g. | | | making or obtaining new | | | substances from Earth\'s spheres. | +-----------------------------------+-----------------------------------+ **\ ** **Elements, compounds and mixtures** **IDENTIFY** that pure substances at standard temperature and pressure have constant physical properties e.g. melting point, boiling point, magnetism, density, solubility and colour (often). ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ **DESCRIBE** pure substances as consisting of either elements or compounds, and mixtures as consisting of more than one type of element and/or compound. **DESCRIBE** at a particle level the difference between elements, compounds and mixtures, including the type and arrangement of particles. **GIVE** specific examples of pure substances and mixtures. All of the matter which surrounds us can be classified either as a pure substance or as a mixture. Pure substances and mixtures each have their own specific properties which allow us to distinguish between them. ### **Pure Substances** 1. 2. 3. 4.  ### **Mixtures** 1. 5. 6. 7. #### **Heterogenous and homogenous mixtures** A homogeneous mixture has the same uniform appearance and composition throughout, for instance apple juice. A heterogeneous mixture consists of visibly different substances or phases, for instance, orange juice with pulp. c2f19 #### **Models** **\ ** **Elements, compounds and mixtures questions** **Question 1:** What is the difference between a **mixture** and a **pure substance.**..................................................................................................................................................................................................................................................................................................................... **Question 2:** Classify the following substances as mixtures (M) or pure substances (P). **Substance** **Classification** ----------------------- -------------------- air oxygen soil wine sulfur chromium crystalline rock salt table salt ------------------------------------------------ -- **Question 3:** Consider the following models. ------------------------------------------------ --  --------------------------------------------------------------------------------------------------------------------------- ------- Complete the table following the example given, identifying each model and giving an everyday example of this model type. **6** --------------------------------------------------------------------------------------------------------------------------- ------- **Model** **Pure substance** **Mixture** **Element/s** **Compound/s** **Example** ----------- -------------------- ------------- --------------- ---------------- ------------- I copper II III IV -------------------------------------------------------------------------------------- -- **Question 4:** Consider the diagram below showing models of elements and compounds. -------------------------------------------------------------------------------------- -- http://www.sciencequiz.net/jcscience/jcchemistry/elements\_compounds/images/340x304xelem01.png.pagespeed.ic.LGCkYoRkLA.png +-----------------------------------+-----------------------------------+ | a. For each of the following | **3** | | statements about these | | | models, identify if that | | | statement is TRUE or FALSE. | | +-----------------------------------+-----------------------------------+ +-----------------------------------+-----------------------------------+ | b. Identify which of the models, | **1** | | if any, represent pure | | | substances. | | +-----------------------------------+-----------------------------------+ +-----------------------------------+-----------------------------------+ | **Question 5:** During a | | | practical class, Terry argued | | | that a substance could contain | | | atoms of two different elements | | | and still be a pure substance. | | | Sam argued that Terry was wrong. | | | | | | Explain who was correct and | | | justify your answer. | | +-----------------------------------+-----------------------------------+ |................................. | **3** | |................................. | | |................................. | | |.... | | | | | |................................. | | |................................. | | |................................. | | |.... | | | | | |................................. | | |................................. | | |................................. | | |.... | | | | | |................................. | | |................................. | | |................................. | | |.... | | | | | |................................. | | |................................. | | |................................. | | |.... | | | | | |................................. | | |................................. | | |................................. | | |.... | | +-----------------------------------+-----------------------------------+ **Separating mixtures** A physical property of a pure substance is anything that can be observed without changing the identity of the substance. The observations usually consist of some type of numerical measurement. There are many physical properties, such as: - State at room temperature - Melting and boiling points - Colour - Density - Electrical conductivity - Thermal conductivity - Malleability - Magnetism Mixtures can be separated into its components by physical means. For instance, we may separate a mixture of iron and sand using a magnet as iron is attracted to the magnet, whereas sand is not. **\ ** **Practical: separate iron from sucrose** --------------------------------------------------------------------------- **SEPARATE** iron filings and sucrose from a mixture of iron and sucrose. --------------------------------------------------------------------------- The physical property that we are going to use to separate them is magnetism. **Aim:** to separate iron and sucrose using physical properties. **Equipment** - magnet - glad wrap - mixture of iron and sucrose in a beaker - spare beaker **Method** 1. Wrap the magnet carefully in glad wrap so that none of the magnet is uncovered. 2. Place the wrapped magnet into the beaker of iron and sucrose. 3. Move the magnet around so that it picks up as much of the iron as possible. 4. Using your fingers, take off as much iron as possible and put it into the spare beaker. 5. Unwrap the magnet keeping all of the iron filings in the glad wrap. Transfer the glad wrap across to the spare beaker and tip all of the iron filings into the spare beaker. **Conclusion** Write a conclusion that explains how you used physical properties to separate iron and sucrose. -- -- -- -- **Questions** 1. How could we have used the physical property of solubility in water to separate iron and sucrose? -- -- -- -- 2. Why did we wrap the magnet in glad wrap? -- -- -- -- **Solutions** ----------------------------------------------------------------------------- **DESCRIBE** aqueous mixtures using the words solute, solvent and solution. -----------------------------------------------------------------------------  As we have already established, it is very difficult to obtain pure substances. It is also difficult to obtain samples of pure water, since many substances can easily get into water. For example, when sugar is added to a glass of water, the sugar crystals disappear or **dissolve** in the water. When a solid dissolves in a liquid a **solution** forms. Solutions represent an important type of mixture and can be found in a vast number of situations. Solutions have some common characteristics. The solid which dissolves is called a **solute**. The liquid in which it dissolves is called the **solvent**. Therefore, a solution is the mixture produced when a solute dissolves in a solvent. In the sugar solution described above, sugar is the solute and water is the solvent. Solutions are special because they are mixtures which have the same properties throughout. Solutions always look the same throughout, they may be coloured but are always clear, i.e. they are transparent, and therefore you can see through them. Other special characteristics of a solution are that: - the solute particles spread evenly throughout the solvent. - it is not easy to separate the solute from the solvent. A substance which dissolves easily is said to be **soluble**, e.g. salt or sugar in water. However, if you try to dissolve sand in water the sand will not dissolve. The sand is said to be **insoluble**. Water is an excellent solvent and is often referred to as the **universal** **solvent** because many substances readily dissolve in it. However other solvents must sometimes be used to dissolve particular substances. ------------------------ -------------------- **Solute** **Solvent** oil paint turpentine nail polish acetone biro stains on clothes methylated spirits ------------------------ -------------------- **\ ** **The importance of water as a solvent** -------------------------------------------------------------------------------------------------- **DESCRIBE the importance of water as a solvent in daily life, industries and the environment.** -------------------------------------------------------------------------------------------------- Water is called the \"universal solvent\" because it is capable of dissolving many substances. It means that wherever water goes, either through the air, the ground, or through our bodies, it takes along valuable chemicals, minerals, and nutrients. However, this name isn\'t entirely accurate, since there are some substances (such as oils) that don\'t dissolve well in water.  **Daily life:** Water's role as a solvent helps cells transport and use substances like oxygen or nutrients. Water based solutions like blood help carry molecules to the necessary locations. Thus, water's role as a solvent facilitates the transport of molecules like oxygen for respiration and has a major impact on the ability of drugs to reach their targets in the body.  **Industries:** We can point towards many industries that use water as a solvent to make products such as foods, medicines, fertilisers, paints, pesticides, paper, and adhesives. It is even used as a solvent in mining with metals being processed with water as an essential part of the process. **Environment:** Water acts as an important solvent in our oceans. An important property of seawater in terms of its effect on life in the oceans is the concentration of dissolved nutrients. **Nitrogen and phosphorus** support **the** growth of algae and aquatic plants, which provide food and habitat for fish, shellfish and smaller organisms that live in water. Another critical element for the health of the oceans is the** **dissolved oxygen content. Oxygen in the surface ocean is continuously added across the air-sea interface as well as by photosynthesis; it is used up in respiration by marine organisms and during the decay or oxidation of organic material that rains down in the ocean and is deposited on the ocean bottom. **\ ** **Concentration** ------------------------------------------------------------------------ **UNDERSTAND the terms dilute, concentrated and saturated solutions.** ------------------------------------------------------------------------ Solutions can contain varying amounts of dissolved material. The amount of dissolved material in a stated volume of the solution is known as the concentration of the solution. We can change the concentration of a mixture by changing the amounts of solute or solvent present. In order to compare the resulting mixtures we use two new terms: **dilute** and **concentrated**. A dilute solution is produced when only a small amount of the solute is dissolved in the solvent. A concentrated solution has a large amount of solute dissolved in the solvent. In the same volume of solution, a concentrated solution has more dissolved solute than a dilute solution. Particle model of dilute and concentrated solutions The concentration of a solution is often given as a percentage. For example a 3% sodium chloride solution is a dilute solution, while a 40 % sodium chloride solution is a concentrated solution. To make a 3% solution you need 3 parts of solute in 100 parts. This means that if you wanted to make a 3% solution of sodium chloride you would place 3 g of sodium chloride in 100 mL of water. Colour is another indicator of the degree of concentration of a solution. A concentrated solution of copper sulfate would be a dark blue colour whereas a dilute copper sulfate solution would be light blue in colour. #### **Saturation** There is a limit to how much solute will dissolve in a solvent. For example, if you keep adding salt to water eventually a point will be reached where no more salt will dissolve in the water. When a solution reaches this stage it is said to be **saturated** (it is full up with solute). At any point along the way to this stage a solution is said to be **unsaturated** and more solute can be dissolved. If you continue to add more solute once the solution has reached its saturation point, the solute will sink to the bottom of the container and remain undissolved. The amount of solute which dissolves is also dependent on the temperature of the solvent. The general rule is: *the higher the temperature of the solvent the more solute that dissolves*, i.e. solubility increases with temperature. For example, in 500 mL of water: 175g of salt will dissolve at 10 °C 190g of salt will dissolve at 90 °C **\ ** **Physical and chemical changes** -------------------------------------------------------------------------------------------------------------------------------------------------- **RECALL chemical changes and COMPARE physical and chemical changes** in terms of the arrangement of particles and reversibility of the process. -------------------------------------------------------------------------------------------------------------------------------------------------- A substance can be changed by heating it, mixing it with another substance, adding water to it, and so on. The change that takes place will either be a physical or a chemical change. #### #### **Physical Change** When no new chemical substance is formed, the change is called a **physical** **change**. Physical changes are usually easy to reverse. Related image #### #### **Chemical Change** When a chemical change occurs, at least one new substance is created. It is this that we call a **chemical reaction**. You can tell when a chemical reaction has taken place because: 1. you can see the new substance, for example, you might observe a colour change, a precipitate, or a gas may be given off. 2. energy is taken in or given out during the reaction. This may be in the form of sound, light or heat. For example, although the heat from the Bunsen burner is required to start the reaction between magnesium and oxygen to form magnesium oxide, once the reaction has started, it produces both heat and light energy. Chemical changes are generally more difficult to reverse than physical changes. For example, once wood has been burnt, do you think it would be easy to reverse? In summary: **Physical Changes** **Chemical Changes** ------------------------------ --------------------------------------------------------------------------------------------------------------------------- ----------------------------------------------------------------------------------------------------------------------------------- **Arrangement of Particles** The spacing between particles may change e.g. change of state from liquid to gas when boiling BUT particles stay the same Bonds within the particles are broken and new combinations within the particles may be created e.g. different particles are made. **Reversibility of Process** Relatively easy to reverse e.g. ice to water and water back to ice. Difficult to reverse e.g. burning wood Watch ClickView video: Differences between Physical and Chemical Changes Classify the following as either physical or chemical change ------------------------------- -- Water freezing to make snow Candle burning Cake cooking Lighting the gas on the stove Fireworks exploding Hard boiling eggs Steam on bathroom mirror Bleaching a stain Adding salt to water Melting chocolate Using a Bunsen burner ------------------------------- -- **\ ** **Separating solutions -- Evaporation and crystallisation** **SEPARATE** a solute from a solution by evaporation and crystallisation and **IDENTIFY** situations when these techniques would be appropriate. -------------------------------------------------------------------------------------------------------------------------------------------------- **IDENTIFY** that a physical change has occurred in the process of evaporation. No new chemicals have been formed. ### **Separating Solutions** In a solution, the solute particles are small enough to pass through the holes in filter paper with the solvent, so filtering is not a feasible method of separation. Similarly, because the solute particles have 'disappeared', decantation or centrifuging are also not appropriate. Therefore, new methods must be used to separate such mixtures. #### **Evaporation and Crystallisation** If the solution was formed by a solid being dissolved in a liquid, the two can be separated by gently heating the solution. This procedure causes the solvent to evaporate leaving the pure solid behind (because solids do not easily evaporate) in the form of crystals. This method is of great use since it is easy to determine when all of the water has been driven off.  This method of separation is used extensively in the production of salt from seawater. Seawater is pumped on to the land and allowed to sit in large, shallow basins called saltpans. The sun evaporates the water leaving the salt crystals behind which can then be harvested. This method is also used in making raw sugar, where once the juice from sugar cane has had the impurities chemically removed, it is evaporated and the pure raw sugar crystallises out. **Practical: Evaporation and crystallisation** -------------------------------------------------------------------------------------------------------------------------------------------------- **SEPARATE** a solute from a solution by evaporation and crystallisation and **IDENTIFY** situations when these techniques would be appropriate. -------------------------------------------------------------------------------------------------------------------------------------------------- #### **Aim:** To separate a solute from a solution by evaporation. #### **Equipment** 250 mL beaker Evaporating basin 1M copper sulfate solution --------------- ------------------- ---------------------------- Tripod Bunsen burner Hand lens Wire gauze Heat proof mat Solid copper sulfate Filter funnel Wooden skewer Kettle #### #### **Risk assessment:** Below are the hazards associated with copper sulfate solid. Text Description automatically generated Identify: 1. Two precautions you will take when handling copper sulfate \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ 2. How copper sulfate should be discarded \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ #### **Evaporation method:** 1\. Pour enough copper sulfate solution to cover half of the bottom of the evaporating basin. 2\. Carefully place the evaporating basin with the copper sulfate solution on the wire gauze, and heat using a **small** blue flame. Make a drawing of your apparatus. 3\. Gently heat the solution until it has nearly all evaporated, then remove it. **Do not let the solution boil at any time!** Allow the last part of the solution to evaporate in the air. This may require it to be left overnight. 4\. Examine the crystals with the hand lens. Make a drawing of the crystals. ***\ *** #### **Crystalisation method:** 1. Add 50 mL of boiling water to a beaker 2. Add a small amount of copper sulfate to the water. Continue adding small amounts until the solution is saturated. 3. Filter the mixture to collect the saturated copper sulfate solution, leaving the copper sulfate residue in the filter paper. 4. Add a wooden skewer to the beaker for the crystals to form on. 5. Leave the mixture for a week, then record your observations. #### **Results** Draw and describe your crystals in the space below. +-----------------------------------+-----------------------------------+ | #### | #### | +===================================+===================================+ | #### Evaporation method | #### Crystalisation method | +-----------------------------------+-----------------------------------+ #### #### **Questions and Conclusions** 1\. What was the solute in the original solution? What was the solvent? \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ 2\. Where did the solvent go on heating? \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ 3\. Compare the crystal size when allowed to crystalise at room temperature versus evaporated with a Bunsen burner. \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ **Solutions questions** +-----------------------------------+-----------------------------------+ | **Question 1:** Initially a pupil | | | had a 100ml beaker half full of a | | | clear solution of salt water. He | | | then: | | | | | | What are the corresponding terms | | | used to describe the nature of | | | the salt solution: | | +-----------------------------------+-----------------------------------+ | a. After Step i. | **2** | | | | | | | | | | | b. After Step ii. | | +-----------------------------------+-----------------------------------+ | **Question 2:** Draw lines to | **3** | | link the following terms with | | | their correct descriptions so | | | that each is only used once. | | +-----------------------------------+-----------------------------------+ **Term Description** +-----------------------------------------------------------------------+ | saturated a large amount of solute is dissolved in a fixed volume of | | solvent | | | | solution contains more than one type of substance | | | | concentrated forms when some solute dissolves in a solvent | | | | mixture when no more solute will dissolve at that temperature | +-----------------------------------------------------------------------+ **\ ** **Question 3:** The following diagram was drawn by a Form I pupil to show the equipment set up for the evaporation of a solvent from a solution. +-----------------------+-----------------------+-----------------------+ | (a) | Identify 4 errors in | **4** | | | this diagram. | | +-----------------------+-----------------------+-----------------------+ | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | | | | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | | | | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | | | | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | +-----------------------+-----------------------+-----------------------+ | (b) | The boy decided to | **3** | | | use this equipment to | | | | separate a mixture of | | | | salt, sugar and water | | | | to obtain pure salt | | | | and pure sugar. | | | | Explain whether this | | | | would be an | | | | appropriate technique | | | | to separate this | | | | mixture. | | +-----------------------+-----------------------+-----------------------+ | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | | | | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | | | | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | | | | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | | | | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | | | | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | +-----------------------+-----------------------+-----------------------+ **\ ** -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- -- **Question 4:** Imagine that you are doing an experiment in which you dissolve four different amounts of an orange-coloured chemical, potassium dichromate, in the same volume of water in four separate beakers. In each case an orange solution forms. The amount of solute and solvent used in each beaker is shown in the table below. -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- -- **Amount of** ------------ --------------- ------------- **Beaker** **Solute** **Solvent** A 10g 50mL B 20g 50mL C 15g 50mL D 5g 50mL +-----------------------+-----------------------+-----------------------+ | a. | Which of the | **1** | | | solutions will have | | | | the deepest orange | | | | colour? | | +-----------------------+-----------------------+-----------------------+ | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |......\... | | | | | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |......\... | | +-----------------------+-----------------------+-----------------------+ | | | | +-----------------------+-----------------------+-----------------------+ | b. | Explain why the | **2** | | | solution you chose in | | | | (a) has the deepest | | | | colour. You must use | | | | the correct | | | | scientific terms in | | | | your answer. | | +-----------------------+-----------------------+-----------------------+ | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |......\... | | | | | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |......\... | | +-----------------------+-----------------------+-----------------------+ | | | | +-----------------------+-----------------------+-----------------------+ | c. | Which two terms would | **2** | | | we use to describe | | | | the solution with the | | | | deepest orange colour | | | | compared to the other | | | | solutions? | | +-----------------------+-----------------------+-----------------------+ | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |......\... | | | | | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |......\... | | +-----------------------+-----------------------+-----------------------+ **\ ** +-----------------------+-----------------------+-----------------------+ | **Question 5:** 100 | | | | mL of solution is | | | | saturated with sodium | | | | chloride and sugar. | | | | | | | | It contains 36 g of | | | | sodium chloride and | | | | 88 g of sugar. | | | +-----------------------+-----------------------+-----------------------+ | | | | +-----------------------+-----------------------+-----------------------+ | a. | What is the maximum | **1** | | | mass of sodium | | | | chloride and sugar | | | | that can dissolve in | | | | water to produce 25 | | | | mL of a solution that | | | | is saturated with | | | | both compounds? | | +-----------------------+-----------------------+-----------------------+ | | Maximum mass of | | | | sodium chloride : | | | | | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | +-----------------------+-----------------------+-----------------------+ | | Maximum mass of | | | | sugar: | | | | | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | +-----------------------+-----------------------+-----------------------+ | | | | +-----------------------+-----------------------+-----------------------+ | b. | The volume of a 100 | **2** | | | mL sample of the | | | | solution contained 20 | | | | g of sodium chloride | | | | and 20 g of sugar. If | | | | this solution was | | | | then reduced to 25 mL | | | | by evaporation, what | | | | mass of sodium | | | | chloride and sugar | | | | (if any at all) will | | | | crystalise out of the | | | | solution. | | +-----------------------+-----------------------+-----------------------+ | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | | | | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | | | | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | | | | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | +-----------------------+-----------------------+-----------------------+ **\ ** **Suspensions** **SEPARATE** a suspension by the process of filtration and **IDENTIFY** situations when this technique would be appropriate. -------------------------------------------------------------------------------------------------------------------------------------------------------------------- **DEFINE** the terms filtrate and residue. **SEPARATE a suspension by the process of sedimentation, decanting, sieving and centrifuging and IDENTIFY situations when these techniques would be appropriate.** When an insoluble substance, e.g. soil, is added to a beaker of water several things will be observed: 1. 2. If this happens, a **suspension** is said to have been formed. Suspensions are different from solutions in that in a suspension: \(a) much of the substance remains undissolved, and \(b) the solid and the liquid can be readily separated by filtering. Orange juice is an example of a suspension. If you buy a bottle of orange juice which has been sitting on a shop shelf you will notice that large chunks of orange have settled on the bottom of the bottle. When you shake up the orange juice the chunks of orange move throughout the liquid but do not dissolve, i.e. they can still be seen. No matter how much you shake the bottle the chunks will never disappear. After shaking, the chunks of orange will once again settle to the bottom of the bottle. Other examples of suspensions include *muddy water and a mixture of chalk and water.* *Sometimes when we try to mix things a mixture is produced with properties intermediate between those of a solution and a suspension. In this case the resulting mixture is cloudy but the tiny particles do not settle out. Such mixtures are called **colloids** or colloidal suspensions. Common examples of colloids include:* 1. 8. 9. 10. ### **\ ** ### **Separating Suspensions** ### **Sedimentation** ### **Decantation** - - #### **Centrifuging** Centrifuging Blood Images, Stock Photos & Vectors \| Shutterstock #### **Filtration** 1. 11. 12. **Practical: Separating suspensions -- sedimentation and decantation** -------------------------------------------------------------------------------------------------------------------------------------------------------------------- **SEPARATE a suspension by the process of sedimentation, decanting, sieving and centrifuging and IDENTIFY situations when these techniques would be appropriate.** -------------------------------------------------------------------------------------------------------------------------------------------------------------------- #### #### **Aim:** To master the process of decanting by separating various suspensions #### **Equipment** 2 x 250 mL beakers sand plastic teaspoon -------------------- ------ ------------------ water soil #### **Method** 1\. Determine the mass of one of the 250 mL beakers containing two table spoons full of sand. Make sure that the beaker is dry. (Why?) Record this mass. 2\. Allow the heavy, solid particles to settle at the bottom of the vessel. 3\. Carefully pour 100-150 mL of water into the beaker. 4\. Bring the second empty beaker underneath the first and carefully pour off all of the water from the first beaker leaving the sand in the first, as illustrated below. When you have poured off all of the water reweigh the first beaker which contains the sand alone. Record this mass. 5\. Repeat the above procedure using the soil.  #### **Results** Record your observations in the space below. -- -- -- -- #### **Questions** 1\. Were the masses of the sand and the soil after the water had been decanted more or less than the original masses? Why might this be so? -- -- -- -- 2\. Which of the two final masses was closest to that of the original mass? Why do you think this is the case? -- -- -- -- 3\. Comment on the success of your efforts at decantation as a method of separating mixtures. -- -- -- -- **\ ** **Practical: Separating suspensions -- sieving** -------------------------------------------------------------------------------------------------------------------------------------------------------------------- **SEPARATE a suspension by the process of sedimentation, decanting, sieving and centrifuging and IDENTIFY situations when these techniques would be appropriate.** -------------------------------------------------------------------------------------------------------------------------------------------------------------------- #### #### **Aim:** To separate a soil sample using sieves #### **Equipment** -------- ------ -- Sieves soil -------- ------ -- Mesh number Size (microns) Size (mm) ------------- ---------------- ----------- 5 4000 4 10 2000 2 35 500 0.5 60 250 0.25 120 125 0.125 #### **Method** 1. Collect 100 g of a soil sample and add it to the stack of sieves containing mesh numbers 5, 10, 35, 60, and 120. 2. Weigh the amount of soil that is collected at each mesh number. Record your results. **Results:** Collected at mesh number: Mass (g) ------------------------------- ---------- 5 10 35 60 120 Went through all mesh numbers **\ ** **Practical: Separating suspensions -- filtering** ------------------------------------------------------------------------------------------------------------------------------ **SEPARATE** a suspension by the process of filtration and **IDENTIFY** situations when this technique would be appropriate. ------------------------------------------------------------------------------------------------------------------------------ #### #### **Aim:** To separate the components of a mixture by filtration. #### **Equipment** filter funnel a piece of filter paper 1 x beaker of muddy water --------------- ------------------------- --------------------------- conical flask 1 x 250 mL beaker glass rod #### #### **Method** 1\. Suspend the filter funnel above the conical flask. 2\. Fold the filter paper in half, then in half again as shown in Figure on the right, and open it out into a cone. 3\. Place the filter paper into the top of the filter funnel and add a small volume of water so the filter paper sticks to the side of the funnel. 4\. Hold the glass rod vertically so that the bottom of the rod is almost touching the filter paper and carefully pour some of the suspension from the beaker down the stirring rod into the filter paper as shown in the diagram. **Precaution**: ensure that you never fill the filter paper above the rim of the cone. 5\. Once some of the liquid has drained through the filter paper carefully top up the funnel with more of the suspension. 6\. When the original beaker is empty of both solid and liquid you should find: \(a) a solid left in the filter paper. This is called the residue. \(b) a liquid left in the flask below the funnel. This is called the filtrate. Time permitting: #### **Results** Draw the apparatus in the space provided below. #### #### #### #### #### #### #### #### #### #### #### #### #### **Questions and Conclusions** 1\. What is the residue left in the filter paper? What is the filtrate? -- -- -- -- 2\. How does the colour of the filtrate compare with that of the original suspension? Account for this difference. -- -- -- -- 3\. Is this method of separation better than decantation? Why? -- -- -- -- **Demonstration: Separating suspensions -- centrifuging** -------------------------------------------------------------------------------------------------------------------------------------------------------------------- **SEPARATE a suspension by the process of sedimentation, decanting, sieving and centrifuging and IDENTIFY situations when these techniques would be appropriate.** -------------------------------------------------------------------------------------------------------------------------------------------------------------------- #### #### **Aim:** To understand the workings of a centrifuge and its applications. #### **Equipment** ----------------------------- --------------------------- ------------------------ *1 x beaker of muddy water* *a laboratory centrifuge* *2 x centrifuge tubes* ----------------------------- --------------------------- ------------------------ #### **Method** *1. Examine the colour of the muddy water suspension and record its colour.* *2. Half fill the two centrifuge tubes with the muddy water suspension.* *3. Place the two tubes on opposite sides of the centrifuge. Turn the centrifuge on and allow it to spin for 1 minute.* *4. Re-examine the two tubes. Make a labelled drawing of what you observe.* #### **Results** *Record your observation in the space provided below.* ---------------- *Before After* ---------------- #### **Questions and Conclusion** *1. How did the appearance of the suspension after it had been centrifuged compare with original muddy suspension?* -- -- -- -- *2. Which is heavier the mud or the water? How can you tell?* -- -- -- -- *3. Why were the two tubes placed on opposite sides of the centrifuge?* -- -- -- -- *4. Why do you think it is not necessary to place a stopper in the top of the centrifuge tubes?* -- -- -- -- *\ * **Suspensions questions** +-----------------------+-----------------------+-----------------------+ | **Question 1:** | | | | Consider the | | | | following diagram. | | | +-----------------------+-----------------------+-----------------------+ | | | | +-----------------------+-----------------------+-----------------------+ | a. | Name this process. | **1** | +-----------------------+-----------------------+-----------------------+ | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | +-----------------------+-----------------------+-----------------------+ | b. | What are the correct | **2** | | | labels for X and Y? | | +-----------------------+-----------------------+-----------------------+ | | X:................... | | | |..................... | | | |..................... | | | |....................\ | | | |... | | | | | | | | Y:................... | | | |..................... | | | |..................... | | | |....................\ | | | |... | | +-----------------------+-----------------------+-----------------------+ | | | | +-----------------------+-----------------------+-----------------------+ | c. | Identify an example | **1** | | | where this process | | | | may be used in the | | | | home. | | +-----------------------+-----------------------+-----------------------+ | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | +-----------------------+-----------------------+-----------------------+ | | | | +-----------------------+-----------------------+-----------------------+ | d. | Identify a physical | **1** | | | property that this | | | | technique relies on. | | +-----------------------+-----------------------+-----------------------+ | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | +-----------------------+-----------------------+-----------------------+ | **Question 2:** | | | | Identify a situation | | | | in which the | | | | following separation | | | | techniques could be | | | | used. | | | +-----------------------+-----------------------+-----------------------+ **Separation Technique** **Situation** -------------------------- --------------- sedimentation decanting sieving -- ------- **3** -- ------- +-----------------------------------+-----------------------------------+ | **Question 3:** | | | | | | a. Draw a scientific diagram of | | | the equipment setup used to | | | filter a suspension of dirt | | | in water. Label the diagram. | | +-----------------------------------+-----------------------------------+ | | **4** | +-----------------------------------+-----------------------------------+ +-----------------------------------+-----------------------------------+ | | | +-----------------------------------+-----------------------------------+ | b. Identify the residue and the | | | filtrate in this experiment. | | +-----------------------------------+-----------------------------------+ | | **1** | +-----------------------------------+-----------------------------------+ **Solutions and suspensions questions** ----------------------------------------------------------------- **EXPLAIN** the difference between a solution and a suspension. ----------------------------------------------------------------- **Question 1:** Draw a particle diagram to represent the following terms. You do not need to draw the water molecules +-----------------------------------------------------------------------+ | Key: | | | | solute particle | +-----------------------------------------------------------------------+ ----------------- ----------------------- -------------------- Dilute solution Concentrated solution Saturated solution ----------------- ----------------------- -------------------- **Question 2:** In an experiment to separate a mixture, a group was given a beaker containing 60% sand and 40% solid sodium chloride. Outline the sequence of processes required to completely separate the sand from the sodium chloride use filtration. (Note: other separation techniques may be needed to ensure purity of the final substances (sand and salt). Your answer can be in the form of a flow chart. \[Hint: processes include drying, decanting, adding water, dissolving, washing, filtering\] +-----------------------------------------------------------------------+ |..................................................................... | |....................................... | | | |..................................................................... | |....................................... | | | |..................................................................... | |....................................... | | | |..................................................................... | |....................................... | | | |..................................................................... | |....................................... | | | |..................................................................... | |....................................... | +-----------------------------------------------------------------------+ **\ ** +-----------------------+-----------------------+-----------------------+ | **Question 3:** | | | | During a practical | | | | lesson, two boys (Tom | | | | and Harry) were | | | | performing an | | | | experiment to | | | | separate an aqueous | | | | blue solution by | | | | evaporation with a | | | | Bunsen burner. At the | | | | end of the experiment | | | | the boys had obtained | | | | a blue solid. | | | +-----------------------+-----------------------+-----------------------+ | | | | +-----------------------+-----------------------+-----------------------+ | a. v | What was the solvent | **1** | | | in this solution? | | +-----------------------+-----------------------+-----------------------+ | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |......\... | | | | | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |......\... | | +-----------------------+-----------------------+-----------------------+ | | | | +-----------------------+-----------------------+-----------------------+ | b. | In the space below, | **5** | | | draw a labelled | | | | diagram using the | | | | Scientist's Code to | | | | show the equipment | | | | set up that the boys | | | | used. | | +-----------------------+-----------------------+-----------------------+ | | | | +-----------------------+-----------------------+-----------------------+ +-----------------------+-----------------------+-----------------------+ | **Question 4:** In | | | | Australia, some | | | | companies produce | | | | table salt on a | | | | commercial basis by | | | | creating very large, | | | | shallow outdoor ponds | | | | of very salty water | | | | which dry out to | | | | produce the salt. | | | +-----------------------+-----------------------+-----------------------+ | | | | +-----------------------+-----------------------+-----------------------+ | a. | Name the separation | **1** | | | process utilised to | | | | produce the salt. | | +-----------------------+-----------------------+-----------------------+ | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |....... | | +-----------------------+-----------------------+-----------------------+ | | | | +-----------------------+-----------------------+-----------------------+ | b. | Give one reason why | **1** | | | filtration of the | | | | initial salt solution | | | | would not be able to | | | | achieve the same | | | | separation. | | +-----------------------+-----------------------+-----------------------+ | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | | | | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | +-----------------------+-----------------------+-----------------------+ +-----------------------------------------------------------------------+ | **Question 5:** A pupil mixed together some fine dirt and water in | | one beaker (Mixture A) and sugar and water in another beaker (Mixture | | B). Both had no solid at the bottom but when a light from a torch was | | shone through Mixture A, the light scattered. When the torch light | | was shone through Mixture B, the beam of light could clearly be seen | | coming through the mixture. Explain the difference between the two | | mixtures. | +-----------------------------------------------------------------------+ |..................................................................... | |........................... | | | |..................................................................... | |........................... | | | |..................................................................... | |........................... | | | |..................................................................... | |........................... | | | |..................................................................... | |........................... | | | |..................................................................... | |........................... | +-----------------------------------------------------------------------+ +-----------------------------------+-----------------------------------+ | **Question 6:** Milk can be | | | considered to be a mixture of fat | | | particles suspended in water. The | | | fat particles are less dense than | | | water and are too small to be | | | filtered out. Describe a process | | | that could be used to separate | | | milk into skim milk and cream. | | +-----------------------------------+-----------------------------------+ |................................. | | |................................. | | |.............................. | | | | | |................................. | | |................................. | | |.............................. | | | | | |................................. | | |................................. | | |.............................. | | | | | |................................. | | |................................. | | |.............................. | | +-----------------------------------+-----------------------------------+ +-----------------------------------+-----------------------------------+ | **Question 7:** Explain the | **3** | | difference between a solution and | | | a suspension, using an example of | | | each type of mixture in your | | | answer. | | +-----------------------------------+-----------------------------------+ |................................. | | |................................. | | |........................... | | | | | |................................. | | |................................. | | |........................... | | | | | |................................. | | |................................. | | |........................... | | | | | |................................. | | |................................. | | |........................... | | | | | |................................. | | |................................. | | |........................... | | | | | |................................. | | |................................. | | |........................... | | +-----------------------------------+-----------------------------------+ **Distillation** ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- **OBSERVE** the separation of an appropriate mixture by simple distillation and **DRAW** a labelled diagram to represent the process. **IDENTIFY** situations in which this technique would be appropriate. ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- During evaporation, we obtain the solute by evaporating the solvent, which is lost into the air. If we wanted to keep the solvent we must somehow try to capture it as a gas and condense it back into a liquid before it escapes into the air. Such a process is called distillation. Distillation is the same as evaporation except that the heating is more rigorous and the solvent is retained by the process. This process is achieved as follows: \(a) the solution is heated in a distillation flask until the contents boil. The gaseous solvent rises and moves into the condenser while the solute remains in the flask. \(b) the gaseous solvent condenses back into a liquid in the condenser. \(c) pure solvent drips from the condenser and is collected in a beaker.  Distillation has a wide number of uses. It can be used to make distilled water from tap water, convert wine into brandy and in the production of oils from plants. **Fractional distillation** Distillation can also be used to separate two or more liquids (with different boiling points) in a mixture. This application is used widely in the petroleum industry and involves a special type of distillation known as fractional distillation. Fractional distillation separates a mixture into a number of different parts, called fractions**.** A tall fractionating column is fitted above the mixture, with several condensers coming off at different heights. The column is hot at the bottom and cool at the top. Substances with high boiling points condense at the bottom and substances with lower boiling points condense on the way to the top. Crude oil is a mixture of hydrocarbons which is separated via fractional distillation. Diagram showing fractional distillation crude oil Vector Image **Distillation demonstration** #### **Aim:** To extract water from a solution using distillation. #### **Equipment:** 1M copper sulfate solution Bunsen burner heat proof mat ----------------------------------------- --------------- ---------------------- distillation apparatus (large quickfit) tripod 250 mL conical flask #### **Method:** 1\. Pour 50 mL of the copper sulfate solution into the distillation flask. Set up the distillation apparatus as shown in Figure 1-9.10. Draw a scientific diagram of your set up. 2\. Gently heat the solution using a small blue flame. 3\. Turn on the tap so that you get a steady flow of water through the outer part of the condenser. 4\. Allow the solution to boil and note the temperature at which droplets first emerge from the condenser. Do not allow the solution to boil dry. 5\. Examine the liquid collecting in the conical flask. #### **Results** Draw a diagram of the apparatus using the Scientists' Code. #### #### #### #### #### #### #### #### #### **Questions and Conclusions** 1\. How does the colour of the solvent collected in the beaker differ from that of the original solution? Why is this so? -- -- -- -- 2\. What is the function of the water flowing through the condenser? -- -- -- -- 3\. Why is it important that all of the stoppers fit properly? -- -- -- -- **Distillation questions** ----------------------------------------------------------------------------------------------------------------------------------------------------------- -- **Question 1:** A boy wanted to obtain pure water from a cola soft drink which was made up of cola syrup and water. He used the equipment as shown below. ----------------------------------------------------------------------------------------------------------------------------------------------------------- --  +-----------------------+-----------------------+-----------------------+ | a. | What physical | **1** | | | property is the boy | | | | using in this | | | | separation? | | +-----------------------+-----------------------+-----------------------+ | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |......\... | | +-----------------------+-----------------------+-----------------------+ +-----------------------+-----------------------+-----------------------+ | b. | Identify each of the | **3** | | | pieces of equipment | | | | labelled, or the | | | | process occurring at: | | +-----------------------+-----------------------+-----------------------+ | | A: | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |..... | | | | | | | | B: | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |..... | | | | | | | | C: | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |..... | | +-----------------------+-----------------------+-----------------------+ | | D: | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |..... | | +-----------------------+-----------------------+-----------------------+ | | | | +-----------------------+-----------------------+-----------------------+ | c. | Explain the function | **2** | | | of the apparatus | | | | labelled C. | | +-----------------------+-----------------------+-----------------------+ | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |......\... | | | | | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |......\... | | | | | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | +-----------------------+-----------------------+-----------------------+ --------------------------------------------------------------------------------------------------------------------------------- -- **Question 2:** The diagram below shows the separation of crude oil (a mixture of solids and liquids) into its main components. --------------------------------------------------------------------------------------------------------------------------------- -- http://www.emec.com.eg/resources/images/production-chemicals/ecc-oil-refinery-chemicals.jpg +-----------------------+-----------------------+-----------------------+ | | | | +-----------------------+-----------------------+-----------------------+ | (a) | Which physical | **1** | | | property is used in | | | | this separation | | | | process? | | +-----------------------+-----------------------+-----------------------+ | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | +-----------------------+-----------------------+-----------------------+ | (b) | Use the diagram and | **3** | | | your knowledge of | | | | separation processes | | | | to explain how the | | | | different 'fractions' | | | | (components) are | | | | separated. | | +-----------------------+-----------------------+-----------------------+ | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | | | | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | | | | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ | | | | | | | |..................... | | | |..................... | | | |..................... | | | |..................... | | | |........ |