Chemistry · 7.3 Preparation of salts · Paper 5/6 practical
Salt Preparation. Make a crystal.
Three routes to a pure salt: a soluble salt from an insoluble base (excess solid), a soluble salt by titration, and an insoluble salt by precipitation. Step through each method and learn why every stage is needed.
0620 Topic 7.3 — Preparation of salts
filter · evaporate · crystallise
Paper 5/6 — Practical
Step 1
Target salt
Making
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Equation
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Procedure checklist
📋 Why each step matters
- Choose a method to see the reasoning.
⚠ Common errors
- Insoluble base method: add the base in excess so all the acid reacts; the unreacted excess is then easy to filter off.
- Heat the filtrate to the point of crystallisation (a saturated solution), not to dryness, or you bake the crystals and they lose shape/water of crystallisation.
- Titration method: there is no solid to filter, so you must first find the exact volume with an indicator, then repeat without indicator using that volume so the salt is not contaminated.
- Precipitation: wash the precipitate with distilled water to remove soluble impurities, then dry it.
🎯 Syllabus reference (0620)
- 7.3 Preparation of salts — describe the preparation, separation and purification of soluble salts (excess insoluble reactant; titration) and insoluble salts (precipitation); know which salts are soluble/insoluble.