Core Practical: Preparing Copper Sulfate Flashcards
All 4 cards in this deck
Why must excess insoluble base be added to the acid when preparing a soluble salt?
To make sure all of the acid reacts, so only salt and water remain in solution.
How can you tell the insoluble base added to an acid is in excess?
Solid remains at the bottom and no more of it dissolves (no more fizzing if a carbonate).
What are the steps of the core practical to make pure, dry hydrated copper sulfate crystals?
e.g. starting from copper oxide and dilute sulfuric acid
- Add excess copper oxide to warm dilute sulfuric acid and stir until no more dissolves.
- Filter off the unreacted copper oxide.
- Evaporate the filtrate in an evaporating basin over a water bath, then leave to crystallise and pat dry.
Why is a water bath used instead of direct heating when evaporating copper sulfate solution?
It heats gently and slowly, so the crystals form properly and the hydrated crystals are not decomposed.