The Art of Crystal Growing
📖 The Art of Crystal Growing
Making salts is like following a recipe! You combine ingredients (acid + base/metal/carbonate), heat gently (like simmering), filter out the unwanted bits (like straining), then let the water evaporate (like reducing a sauce). The key is knowing when you've added enough "ingredients" — add too much acid and you'll need to start again!
Chemistry glossary
- What is crystallisation?
- The process of forming solid crystals from a saturated solution
The method you use depends on whether your salt dissolves in water. Most salts are soluble, but some are insoluble and need a different approach.
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🧠 Memory Aids
Soluble salt method — "FECD": Filter, Evaporate, Cool, Dry — the four steps after the acid-base reaction is complete.
Why add excess base: "BASE beats ACID" — always use excess of the insoluble base so all acid is consumed. "Excess base in, excess base removed by filter." Excess acid in = problem (acid stays in product).
Insoluble salts: "Silver CHLORIDE is WHITE, Lead IODIDE is YELLOW, Barium SULFATE is WHITE." These are the three insoluble salts most commonly tested.
Solubility rules shortcut: "ALL nitrates dissolve. ALL sodium/potassium/ammonium salts dissolve. Most chlorides and sulfates dissolve, EXCEPT the named exceptions." Learn the exceptions: silver chloride, barium sulfate, lead chloride, lead sulfate, lead iodide.
Now try it yourself
Quiz · Question 1 of 20
Which of the following is the correct method for making copper sulfate crystals from copper oxide and sulfuric acid?
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This topic in real past papers
Every real exam question we've found on making salts, with a full worked answer.
AQA Paper 1
Plan a method to make pure, dry crystals of a soluble salt from an insoluble base/carbonate and a dilute acid, or plan a method to investigate a variable affecting temperature change.
AQA Paper 1
Plan an investigation to identify three unknown metals by comparing their reactions with a dilute acid.