Acids, bases and salts · Grade 10
Making a salt: copper(II) sulfate crystals
ChemAI · Worksheet
NameClassDate
Aim
React an insoluble base with an acid, filter off the excess and crystallise the salt.
⚠ Hot acid: goggles. Never heat the dish to dryness — it spits.
Before you start: what do you predict will happen? Why?
What you do
| Step | What I observed | |
|---|---|---|
| 1 | Heat the acid gently and add copper(II) oxide until some black powder stays undissolved (excess). Speed ×5 helps. | |
| 2 | Stop heating. Press “Filter” on the beaker, then click the evaporating dish. The black excess stays in the filter paper. | |
| 3 | Heat the dish (speed ×20) until crystals appear at the edge, then stop heating. | |
| 4 | Let it cool: more blue crystals grow. (Heated to dryness they would turn white.) |
Questions
- Write a word or symbol equation for one reaction you observed.
- Explain your most important observation using particles, ions or energy.
- Was your prediction right? What would you change to get a more reliable result?