"},{"color":"green","style":"text-color-with-background","anchor":"copper_metal"}]},"order":2,"title":"Complete the equation","description":"Only the particles that change remain in the ionic equation. This complete equation earns the B1 mark."}]}],"generatedAt":"2026-07-21T03:12:00.731Z","modelVersion":"gpt-5.6-terra","explanationVersion":"v3"},"options":[]},{"id":"414f6938-339c-4719-baa3-1202c0c2f8e7","label":"f","content":"Why is magnesium described as being oxidised in this reaction?","markscheme":"- States that magnesium (atoms) lose electrons B1","marks":1,"order":5,"markingRubric":null,"explanation":{"methods":[{"id":"electron_loss","label":"Use electron transfer","steps":[{"type":"text","order":1,"title":"State electron loss","content":"Magnesium is oxidised because magnesium atoms lose electrons. [B1]"}]}],"generatedAt":"2026-07-21T03:13:25.246Z","modelVersion":"gpt-5.6-terra","explanationVersion":"v3"},"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null},{"id":"175bb661-cd71-4008-ad0f-483130df3be0","revisionId":"bfe4f77a-8bfb-406b-9573-2da45571c4cb","questionNumber":null,"questionType":"LA","specification":"This question is about preparing a soluble salt.","difficulty":4,"difficultyBand":"medium","totalMarks":8,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"f7ab5e73-55ee-45a0-917a-7afa65ba9c04","label":"a","content":"Plan a method to make pure, dry crystals of zinc sulfate from zinc carbonate and a dilute acid.","markscheme":"- State that the dilute acid used is sulfuric acid ($H_2SO_4$) B1\n- Add zinc carbonate to the sulfuric acid in a beaker and stir, continuing to add until the zinc carbonate is in excess (until no more fizzing/effervescence is observed and solid remains at the bottom) M1\n- Filter the mixture using filter paper and a funnel to remove the excess, unreacted zinc carbonate, leaving a clear zinc sulfate filtrate M1\n- Heat the filtrate gently in an evaporating basin to evaporate some water until the crystallisation point is reached M1\n- Leave the saturated solution to cool and crystallise M1\n- Filter/decant the crystals and dry them by patting with filter paper or leaving them in a warm place A1","marks":6,"order":0,"markingRubric":null,"explanation":{"methods":[{"id":"crystallisation","label":"Making crystals by crystallisation","steps":[{"type":"text","order":0,"title":"Choose the acid","content":"Use **dilute sulfuric acid**, $\\mathrm{H_2SO_4}$. It provides the sulfate part of the salt, so reacting it with zinc carbonate makes zinc sulfate. This is the first mark (B1).","highlights":[{"text":"zinc sulfate from zinc carbonate and a dilute acid","location":"specification"}]},{"type":"text","order":1,"title":"React the carbonate","content":"Put dilute sulfuric acid in a beaker. Add zinc carbonate a little at a time and stir. It will fizz because carbon dioxide is produced.\n\nKeep adding zinc carbonate until the fizzing stops **and** some solid remains at the bottom. The remaining solid shows that the acid has all reacted: zinc carbonate is now in excess. This earns M1.","highlights":[{"text":"zinc carbonate and a dilute acid","location":"specification"}]},{"type":"text","order":2,"title":"Remove excess solid","content":"Filter the mixture through **filter paper in a funnel**. The excess, unreacted zinc carbonate stays as the residue on the paper. Collect the clear filtrate, which is zinc sulfate solution. This earns M1.","highlights":[{"text":"pure, dry crystals of zinc sulfate","location":"specification"}]},{"type":"text","order":3,"title":"Concentrate the solution","content":"Pour the clear filtrate into an evaporating basin. Heat it **gently** to evaporate some water, stopping when the crystallisation point is reached: the solution is concentrated enough that crystals will form as it cools. This earns M1.\n\nDo not heat it until all the water has gone, as this would not give well-formed crystals.","highlights":[{"text":"pure, dry crystals","location":

Reactions of acids

Question 5

Reactions of acids Questions

Reactions of acids

Question 5

Reactions of acids Questions