Spot the new substance
An irreversible change makes a new substance and cannot easily be undone. Look for the signs that tell you a new substance has formed.
Q1. Mix the vinegar and bicarbonate of soda (goggles on!). Record what you observe.
Q2. Which signs of a chemical change did you see? Tick all that apply and add detail.
- A colour change
- A gas (bubbles or a smell)
- Heat or light given off
- A new material that won't change back
Q3. Explain why this is an irreversible change.
Q4. Classify each change as reversible or irreversible, and give a reason.
| Change | Reversible or irreversible? | Reason |
|---|---|---|
| Rusting a nail | ||
| Freezing water | ||
| Toasting bread | ||
| Tearing paper |