Word Equations
Year 7 ⚗️ Chemical Reactions Write and interpret word equations; apply conservation of mass.
📝 Word Equations
A word equation describes a chemical reaction using the names of reactants and products.
Format
$$\text{Reactant 1} + \text{Reactant 2} \rightarrow \text{Product 1} + \text{Product 2}$$Example: magnesium + oxygen → magnesium oxide
Example: hydrochloric acid + sodium hydroxide → sodium chloride + water
Example: hydrochloric acid + sodium hydroxide → sodium chloride + water
⚖️ Conservation of Mass
Mass is always conserved. Total mass of reactants = total mass of products.
Example: Iron (56 g) + Sulfur (32 g) → Iron sulfide (88 g). 56 + 32 = 88 ✓
In an open system, gases may escape — the solid/liquid mass may appear to decrease.
🔤 Common Reaction Patterns
| Reaction type | Word equation pattern |
|---|---|
| Combustion | fuel + oxygen → carbon dioxide + water |
| Neutralisation | acid + alkali → salt + water |
| Metal + acid | metal + acid → salt + hydrogen |
| Metal + oxygen | metal + oxygen → metal oxide |
| Carbonate + acid | carbonate + acid → salt + water + CO₂ |
Ready to test yourself? Click the Quiz tab above to practise questions on this topic!
Interactive Demonstration — Word Equations
Complete each word equation by choosing the correct product(s).
Select the correct product for each reaction.
📝 Reaction Type Identifier
Calculate moles from mass and molar mass (needed for balancing equations).