What happens when (give balanced equations):
Ethene is burnt in excess of oxygen.

Explanation

To determine what happens when ethene (C₂H₄) is burnt in excess oxygen, we need to write and balance the chemical equation for the combustion reaction.

### Step-by-Step Solution:

1. **Identify the Reactants and Products**:
- Reactants: Ethene (C₂H₄) and oxygen (O₂).
- Products: Carbon dioxide (CO₂) and water (H₂O).

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