Identifying substances · Grade 10
Copper and ammonia: royal blue
ChemAI · Worksheet
NameClassDate
Aim
A precipitate that dissolves again in excess reagent — a complex ion.
⚠ Ammonia solution has an irritating vapour: work in a fume cupboard.
Before you start: what do you predict will happen? Why?
What you do
| Step | What I observed | |
|---|---|---|
| 1 | Set the amount to 1 mL and add aqueous ammonia once: a pale blue precipitate. | |
| 2 | Keep adding ammonia, 1 mL at a time, until the precipitate dissolves. |
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?