[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-0-en-105":3,"doc-seo-207405-105":59,"doc-detail-207405-en":125},{"code":4,"msg":5,"data":6},0,"success",[7,13,18,23,28,33,38,43,48,51,55],{"id":8,"doc_module":4,"doc_module_name":9,"category_name":10,"show_sort_weight":11,"slug":12},1,"Document","Story & Novel",90,"story-novel",{"id":14,"doc_module":4,"doc_module_name":9,"category_name":15,"show_sort_weight":16,"slug":17},2,"Literature",80,"literature",{"id":19,"doc_module":4,"doc_module_name":9,"category_name":20,"show_sort_weight":21,"slug":22},4,"Exam",70,"exam",{"id":24,"doc_module":4,"doc_module_name":9,"category_name":25,"show_sort_weight":26,"slug":27},5,"Comic",60,"comic",{"id":29,"doc_module":4,"doc_module_name":9,"category_name":30,"show_sort_weight":31,"slug":32},6,"Technology",50,"technology",{"id":34,"doc_module":4,"doc_module_name":9,"category_name":35,"show_sort_weight":36,"slug":37},7,"Healthcare",40,"healthcare",{"id":39,"doc_module":4,"doc_module_name":9,"category_name":40,"show_sort_weight":41,"slug":42},8,"Research & Report",30,"research-report",{"id":44,"doc_module":4,"doc_module_name":9,"category_name":45,"show_sort_weight":46,"slug":47},9,"Religion & Spirituality",20,"religion-spirituality",{"id":46,"doc_module":4,"doc_module_name":9,"category_name":49,"show_sort_weight":46,"slug":50},"World Cup","world-cup",{"id":52,"doc_module":4,"doc_module_name":9,"category_name":53,"show_sort_weight":52,"slug":54},10,"Lifestyle","lifestyle",{"id":56,"doc_module":4,"doc_module_name":9,"category_name":57,"show_sort_weight":24,"slug":58},19,"General","general",{"code":4,"msg":60,"data":61},"ok",{"site_id":62,"language":63,"slug":64,"title":65,"keywords":66,"description":67,"schema_data":68,"social_meta":118,"head_meta":120,"extra_data":122,"updated_unix":124},105,"en","aqa-gcse-chemistry-topic-8-chemical-analysis","AQA GCSE Chemistry Topic 8 - Chemical Analysis","","GCSE Chemistry Topic 8: Chemical Analysis practice questions and answer guidance covering how to define and distinguish pure and impure substances, and predicting how impurities affect melting and boiling points. Includes formulation concepts with everyday examples, chromatography principles (separating soluble substances, mobile vs stationary phase, describing the Rf method, and interpreting chromatograms). Covers tests for gases such as oxygen, hydrogen, and carbon dioxide, interpreting observations like limewater changes, and basic flame emission, precipitation, and instrumental vs chemical analysis comparisons.",{"@graph":69,"@context":117},[70,84,100],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":20,"@type":76,"position":81},"https://docshare.wps.com/document/exam/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/aqa-gcse-chemistry-topic-8-chemical-analysis/207405/",{"url":83,"name":65,"@type":85,"author":86,"headline":65,"publisher":89,"fileFormat":92,"inLanguage":63,"description":67,"dateModified":93,"datePublished":94,"encodingFormat":92,"isAccessibleForFree":95,"interactionStatistic":96},"DigitalDocument",{"name":87,"@type":88},"Aria","Person",{"url":74,"name":90,"@type":91},"DocShare","Organization","application/pdf","2026-09-09","2026-09-05",true,{"@type":97,"interactionType":98,"userInteractionCount":24},"InteractionCounter",{"@type":99},"ViewAction",{"@type":101,"mainEntity":102},"FAQPage",[103,109,113],{"name":104,"@type":105,"acceptedAnswer":106},"How can you distinguish a pure substance from an impure substance?","Question",{"text":107,"@type":108},"Melting and boiling points help distinguish substances. For example, pure water boils at 100°C.","Answer",{"name":110,"@type":105,"acceptedAnswer":111},"What happens to melting and boiling points when impurities are present?",{"text":112,"@type":108},"Impurities lower the melting point and raise the boiling point of the sample.",{"name":114,"@type":105,"acceptedAnswer":115},"How does the Rf value help you identify a substance in chromatography?",{"text":116,"@type":108},"Each solvent has a different Rf value, so the substance’s Rf can be compared to identify it.","https://schema.org",{"og:url":83,"og:type":119,"og:title":65,"og:site_name":90,"og:description":67},"article",{"robots":121,"canonical":83},"index,follow",{"doc_id":123,"site_id":62},207405,1788599422,{"code":4,"msg":5,"data":126},{"doc_id":123,"user_id":127,"nickname":87,"user_avatar":128,"doc_module":4,"category_id":19,"category_name":20,"doc_title":65,"doc_description":67,"doc_content":129,"file_id":130,"file_url":131,"file_type":132,"file_size":133,"view_count":24,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":19,"language":134,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":135,"faqs":136,"seo_title":137,"seo_description":67,"update_tm":124,"read_time":52},2336464648322,"https://ap-avatar.wpscdn.com/avatar/2200025388227c56fec?_k=1778556882303663488","AQA GCSE Chemistry Topic 8: Chemical Analysis  \n\n| a\u003Cbr>Define a pure substance.\u003Cbr>|\n| --- |\n|  |\n| How can you distinguish a pure substance from an impure substance? |\n|  |\n|  |\n| What will happen to the above if there are impurities in the sample? |\n|  |\n|  |\n\n\n| b\u003Cbr>What is a formulation?\u003Cbr>|\n| --- |\n|  |\n|  |\n|  |\n| Give some everyday examples of where formulations are used.\u003Cbr>1.  \u003Cbr>2.  \u003Cbr>3.  \u003Cbr>4.  \u003Cbr>5.  \u003Cbr>6.   |\n\n\n| c\u003Cbr>What does chromatography separate?\u003Cbr>|\n| --- |\n| \u003Cbr>Describe how the process works. Use the diagram to help. |\n|  |\n|  |\n|  |\n|  |\n| Complete the word equation for calculating the Rf value.\u003Cbr>Rf =  \u003Cbr>How does the Rf value allow you to identify a substance? |\n|  |\n|  |\n\nd  \nWhat colour does litmus go if chlorine is present?  \n1  \n| e\u003Cbr>What is the Rf value of the following chromatogram?\u003Cbr>The distance moved by substance B is 30mm and the distance moved by solvent A is 52mm.\u003Cbr>|\n| --- |\n|  |\n|  |\n|  |\n|  |\n|  |\n|  |\n\nf  \nWhat are the 2 phases of chromatography?  \n|  |\n| --- |\n|  |\n|  |\n|  |\n|  |\n|  |\n|  |\n\n1.  \n2.  \n\n| Describe the test for oxygen. g\u003Cbr>|\n| --- |\n|  |\n|  |\n|  |\n|  |\n|  |\n\nh  \nWhat gas does this experiment test for?  \ni  \nWhat gas does this experiment test for?  \nWhat colour does the limewater go if the gas is present?  \n\n| I | understand the following topic… | j\u003Cbr>|\n| --- | --- | --- |\n| I | need to work on the following topic… |  |\n|  |  |  |\n\nvisit [twinkl.com](twinkl.com)  \nAQA GCSE Chemistry Topic 8: Chemical Analysis  \n\n| Match the metal to the colour flame it produces by connecting with a straight line.\u003Cbr>lithium sodium potassium calcium copper\u003Cbr>| a\u003Cbr>|\n| --- | --- |\n\nb  \nTransition metal compounds produce coloured precipitates when mixed with sodium hydroxide solution. Complete the table to show the colour of the different precipitates.  \n| Transition Metal Ion | Precipitate Colour |\n| --- | --- |\n| Al³+ , Ca²+ , Mg²+ | white |\n| Cu²+ |  |\n| Fe²+ |  |\n| Fe³+ |  |\n\n\n| NaHCO₃ (aq) + HCl (aq)    (aq) +   (g) +   (l) | c\u003Cbr>|\n| --- | --- |\n\nd  \nWhen mixed with a solution of silver nitrate and dilute nitric acid, halide ions form coloured precipitates.  \n• Silver   produces a white precipitate.  \n• Silver   produces a cream precipitate.  \n• Silver   produces a yellow precipitate.  \n| Why are instrumental methods, e.g. spectroscopy, more useful than chemical analysis methods? | e\u003Cbr>|\n| --- | --- |\n|  |  |\n\n\n| f\u003Cbr>Explain how flame emission spectroscopy can be used to\u003Cbr>|\n| --- |\n| identify the elements in an unknown sample. |\n|  |\n|  |\n\n2  \n| Look at the spectroscopy results below.\u003Cbr>\u003Cbr>| g\u003Cbr>\u003Cbr>Ca2+\u003Cbr>Mg2+\u003Cbr>Al³+\u003Cbr>Fe3+\u003Cbr>X |\n| --- | --- |\n| Which metal ions are contained in sample X?   |  |\n\nvisit [twinkl.com](twinkl.com)  \nAQA GCSE Chemistry Topic 8: Chemical Analysis Answers  \n\n| Define a pure substance.\u003Cbr>When nothing has been added to a substance. | a\u003Cbr>|\n| --- | --- |\n| How can you distinguish a pure substance from an impure substance?\u003Cbr>The melting and boiling points of substances allow you to distinguish one substance from another. e.g. pure water boils at 100°C.\u003Cbr>What will happen to the above if there are impurities in the sample?\u003Cbr>They will lower the melting point.\u003Cbr>They will increase the boiling point. |  |\n\nWhat is a formulation?  \nUseful mixtures that have a particular use.  \nGive some everyday examples of where formulations are used.  \npaint, fertilisers, cleaning products, fuels, cosmetics, nail polish, perfume, medicine, pesticides, inks.  \nb  \nc  \nWhat does chromatography separate?  \nIt separates 2 or more soluble substances in a mixture.  \nDescribe how the process works. Use the diagram to help.  \nThe solvent moves up the paper. As it moves, it takes the mixture with it.  \nThe more soluble the substance, the farther it moves up the paper.  \nSome are not as soluble so do not travel as far. They separate into different spots.  \nComplete the word equation for calculating the Rf value.  \ndistance moved by substance (B) Rf = ~~ ~","cbCailbm5FjWadvH","https://ap.wps.com/l/cbCailbm5FjWadvH","pdf",904230,"English","# Chemical analysis fundamentals\n## Pure vs impure substances\n## Formulations\n# Chromatography\n## What chromatography separates\n## Rf value and identification\n## Phases of chromatography\n## Gas tests and observations\n# Flame emission and precipitation\n## Matching flame colours\n## Colored precipitates and halides","[{\"question\":\"How can you distinguish a pure substance from an impure substance?\",\"answer\":\"Melting and boiling points help distinguish substances. For example, pure water boils at 100°C.\"},{\"question\":\"What happens to melting and boiling points when impurities are present?\",\"answer\":\"Impurities lower the melting point and raise the boiling point of the sample.\"},{\"question\":\"How does the Rf value help you identify a substance in chromatography?\",\"answer\":\"Each solvent has a different Rf value, so the substance’s Rf can be compared to identify it.\"}]","AQA GCSE Chemistry Topic 8 - Chemical Analysis | PDF"]