The fizzing reaction
An irreversible change makes a brand-new substance and can't be undone. Look for the four signs: a gas produced, a colour change, heat or light, or a new material.
1. List the signs of chemical change you observed when bicarb soda met vinegar.
2. Explain why this reaction cannot be undone.
Sort the changes (exit ticket)
Sort these four changes. For each one, tick reversible or irreversible and give a reason. Ask yourself: has a new substance been made?
| Change | Reversible or irreversible? | My reason |
|---|---|---|
| Melting ice | ||
| Burning wood | ||
| Dissolving salt | ||
| Rusting nail |