This common misconceptions covers Common Misconceptions within Making Salts for GCSE Chemistry. Revise Making Salts in Chemical Changes for GCSE Chemistry with 20 exam-style questions and 20 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 9 of 13 in this topic. Use this common misconceptions to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 9 of 13
Practice
20 questions
Recall
20 flashcards
⚠️ Common Misconceptions
Misconception 1: "You boil all the water off to get crystals"
Boiling away all the water produces a powdery, impure residue — not beautiful crystals. The correct method is to evaporate only about half the water (until crystals start forming at the edges), then remove from heat and allow to cool slowly. Slow cooling produces large, regular crystals. Overheating copper sulfate also risks losing the water of crystallisation, turning it from blue to white anhydrous copper sulfate.
Misconception 2: "You add excess acid to make sure all the base reacts"
This is the opposite of the correct technique. You add excess base (the insoluble reactant — e.g., copper oxide) to ensure all the acid reacts. Excess acid cannot be easily removed from the final salt. Excess insoluble base is easily removed by filtering.
Misconception 3: "Washing the precipitate removes the salt"
Washing an insoluble precipitate with distilled water removes soluble impurities (like KNO₃ from the lead iodide precipitation) without dissolving the insoluble precipitate itself. You are removing contamination, not the product. Always use distilled water (not tap water) to avoid introducing new impurities.