by crystallisation in a petri dish.](https://assets.mathsgenie.co.uk/aqa-qb/8742caf6-57db-4128-bffd-891ac7787fe6.png)","markscheme":"- Filter the mixture using **filter paper** placed inside a **filter funnel** over a beaker or conical flask M1\n- Identify that the insoluble magnesium oxide remains on the paper as residue, while the clear magnesium sulfate solution is collected as the filtrate A1\n- Transfer the filtrate to an **evaporating basin / dish** and heat gently using a **Bunsen burner**, **tripod**, and **gauze** M1\n- Heat the solution until the crystallization point is reached (when crystals begin to form on a glass rod or at the edges) M1\n- Remove from heat and allow the saturated solution to cool slowly at room temperature to form larger crystals A1\n- Separate the crystals from the remaining liquid (by filtration/decantation), wash them with a small amount of cold distilled water, and dry by patting gently with **filter paper** or placing in a warm oven A1","marks":6,"order":0,"markingRubric":null,"explanation":{"methods":[{"id":"filtration_and_crystallisation","label":"Filtration then crystallisation","steps":[{"type":"text","order":1,"title":"Set up filtration","content":"Because the excess magnesium oxide is insoluble, separate it from the magnesium sulfate solution by filtration. Place **filter paper** inside a **filter funnel** over a beaker or conical flask, then carefully pour the mixture through it. This filtration set-up earns **M1**.","highlights":[{"text":"excess insoluble magnesium oxide","location":"specification"}]},{"type":"text","order":2,"title":"Identify the residue and filtrate","content":"The insoluble magnesium oxide stays on the filter paper; this solid is the **residue**. The clear magnesium sulfate solution that passes into the beaker or conical flask is the **filtrate**. Identifying both correctly earns **A1**.","highlights":[{"text":"clear solution of magnesium sulfate","location":"specification"}]},{"type":"text","order":3,"title":"Concentrate the solution","content":"Transfer the filtrate to an **evaporating basin**. Heat it gently with a **Bunsen burner** on a **tripod and gauze**. This named apparatus earns the next **M1**."},{"type":"text","order":4,"title":"Stop at crystallisation","content":"Evaporate some water, but do not heat until the basin is dry. Stop when the crystallisation point is reached: crystals just begin to appear at the edge of the solution or on a glass rod. This earns **M1**."},{"type":"text","order":5,"title":"Cool to grow crystals","content":"Remove the evaporating basin from the heat and leave the saturated solution to cool slowly at room temperature. Magnesium sulfate crystals form as it cools; slow cooling produces larger crystals. This earns **A1**."},{"type":"text","order":6,"title":"Wash and dry crystals","content":"Separate the crystals from the remaining liquid by filtration (or carefully decant the liquid). Wash the crystals with a small amount of **cold distilled water**, then dry them by gently patting with **filter paper** or using a warm oven. This final purification and drying earns **A1**."}]}],"generatedAt":"2026-07-21T04:30:42.756Z","modelVersion":"gpt-5.6-terra","explanationVersion":"v3"},"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null}],"subjectCode":"gcse_chemistry","summaries":[{"id":"013dfa7b-451f-457f-aa70-ae8f55180834","difficultyBand":"easy","calculatorUse":null},{"id":"01c2a47e-9b3f-4449-8261-7cd9c0d970ac","difficultyBand":"medium","calculatorUse":null},{"id":"048f7605-da2e-4ad7-9c8d-bbba7c7ab5e1","difficultyBand":"medium","calculatorUse":null},{"id":"09df5846-f957-4137-adda-23e044692c8e","difficultyBand":"medium","calculatorUse":null},{"id":"0a32f1a0-8f30-47d4-a583-ff7fe1fbdda9","difficultyBand":"medium","calculatorUse":null},{"id":"0a68be85-9329-4ff4-9728-19563689c2c8","difficultyBand":"easy","calculatorUse":null},{"id":"0be1e0f3-2d1a-4a51-94f6-06b1f8191b7d","difficultyBand":"easy","calculatorUse":null},{"id":

Methods of separating and purifying substances

Question 1

Methods of separating and purifying substances Questions

Methods of separating and purifying substances

Question 1

Methods of separating and purifying substances Questions