Home learning activities 
                                                                     Subject 
                     
                                                                     Science 
                                                                           
                                                                  Year Group 
                                                                           
                                                                      Year 8 
                                                                           
                                                   Unit of work / Knowledge organiser 
                                                                           
                                                  Mixtures and Separation Techniques 
                                                                           
                                                                    Activities 
                     
                        •    Read through Sections 1-7 of the ‘Knowledge Organiser’ on ‘Mixtures and 
                             Separation Techniques’. Make careful and detailed notes on sections 1-3 as 
                             well as writing a list of the separation techniques which are described in the 
                             remaining sections. 
                              
                        •    Without looking at your notes, describe, in your own words, what a mixture is 
                             (compare your answer with Section 1 afterwards).  
                              
                        •    Learn the meanings of the key words from the ‘Mixtures and Separation 
                             Techniques Keywords’ sheet and complete the key words from memory on 
                             the ‘Keywords Test’ sheet. Find your score using the ‘Key Words’ sheet.  
                              
                        •    Read the ‘Key Revision Facts’ sheet carefully. 
                              
                        •    Describe, in your own words, the difference between ‘filtration’, ‘distillation’ 
                             and ‘chromatography’ without looking at the ‘Key Revision Facts’ sheet.  
                              
                        •    Complete the ‘Match and Draw’, ‘Filtration’ and ‘Dissolving’ activities on 
                             the ‘Test Yourself’ pages; the answers are provided at the end, but do not 
                             look at these until you have tried to complete the work yourself (be strict 
                             with yourself here).  
                     
                        •    Complete the exam question on ‘Mixtures and Separation Techniques’. Use 
                             the mark scheme (once you have tried the question) to mark your answers 
                             carefully.  
                     
                                                   Where do you complete the work? 
                                                                           
                                                                In Study Books. 
                     
                                        What to do if you finish the work? (Extension activity) 
                     
                        •    Make sure you have completed the previous set work on ‘Pressure and 
                             Moments’ and then complete the ‘Mini Project’ on ‘Separating Mixtures’. 
                     
                     
                     
                                                               These websites might help: 
                                                                                   
                           •    BBC Bitesize -> Secondary -> KS3 -> Science -> Chemistry -> Separating Mixtures 
                                                                                   
                                        If you are struggling with your work or if you have finished. 
                                                                                   
                          Please email your classroom teacher directly using the email list found in the 
                                                      Home Learning section of the website. 
                       
                                                                                   
         Year 8 — Mixtures and Separation Techniques 
           1.  What is a mixture?                                                               4. Crystallisation  
           A mixture consists of two or more different substances, not chemically joined 
           together. 
           The substances in a mixture can be elements, or compounds, or both. Being part 
           of a mixture does not change the chemical properties of the substances that are 
           in it. 
            
           Examples of mixtures are: Sea water, air, soil and bleach. 
           2. Pure or Impure? 
           A pure substance consists only of one element or one compound. 
           An impure substance is made of two or more elements or compounds that are 
           not bonded together chemically. 
           3. Solutions 
           Mixture formed from a solvent and a solute.                                          5. Filtration 
           Examples of solutions are:                                                           Filtration is a method for separating an 
           Dishwater (soap dissolved in water)                                                  insoluble solid from a liquid. When a 
           Fizzy drinks (carbon dioxide dissolved in water)                                     mixture of sand and water if filtered, 
           Sweet tea (sugar dissolved in solution)                                              the sand stays behind in the filter    
                                                                                                paper (residue) and the water passes 
                                                                                                through the filter paper (filtrate) 
         Year 8 — Mixtures and Separation Techniques 
          6. Distillation 
                                                                                             7. Chromatography 
          Distillation is a method for separating the solvent from a solution. For  exam-
                                                                                             Paper chromatography is a method for separating dissolved substances from 
          ple, water can be separated from salt solution by simple distillation. This meth-
                                                                                             one another. It is often used when the dissolved substances are coloured, 
          od works because water has a much lower boiling point than salt. When the so-
                                                                                             such as inks, food colourings and plant dyes. It works because some of the 
          lution is heated, the water evaporates. It is then cooled and condensed into a 
          separate container. The salt does not evaporate and so it stays behind.            coloured substances dissolve in the solvent used better than others, so they 
                                                                                             travel further up the paper. A pure substance will only produce one spot on 
                                                                                             the chromatogram during paper chromatography. Two substances will be the 
                                                                                             same if they produce the same colour of spot, and their spots travel the 
                                                                                             same distance up the paper. In the example below, red, blue and yellow are 
                                                                                             three pure substances. The sample on the left is a mixture of all three.