Core Practical: Preparing Copper Sulfate Flashcards
All 6 cards in this deck
What are the steps to prepare pure, dry hydrated copper sulfate crystals?
e.g. from copper oxide and dilute sulfuric acid- Warm the acid and add copper oxide until it is in excess (no more dissolves).
- Filter off the excess copper oxide to leave copper sulfate solution.
- Evaporate some of the water using a water bath, leave to crystallise, then pat the crystals dry.
Why is copper oxide added in excess to the dilute sulfuric acid?
To make sure all the acid reacts, so the solution left is only salt and water.
How is the excess copper oxide removed from the copper sulfate solution?
By filtration — the solid stays on the filter paper.
Why is a water bath used instead of heating the copper sulfate solution strongly with a Bunsen burner?
It heats gently, so the solution does not spit and the crystals are not decomposed (they keep their water of crystallisation).
What colour are hydrated copper sulfate crystals?
Blue.
State one safety precaution needed when preparing copper sulfate from copper oxide and sulfuric acid.
Wear eye protection — the dilute sulfuric acid is an irritant/corrosive (also take care with hot apparatus).