Reaction rates · Grade 9
Elephant toothpaste
ChemAI · Worksheet
NameClassDate
Aim
A catalyst, hydrogen peroxide and a little detergent: a fountain of foam.
⚠ 12% hydrogen peroxide burns skin and eyes. Gloves and goggles; the foam is hot.
Before you start: what do you predict will happen? Why?
What you do
| Step | What I observed | |
|---|---|---|
| 1 | Add washing-up liquid to tube 2 only. | |
| 2 | Now add potassium iodide (the catalyst) to tube 2. | |
| 3 | Add potassium iodide to tube 1 (no detergent). What is different? | |
| 4 | Hold a glowing splint at a tube: which gas fills the bubbles? |
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?