Compare a word equation with a balanced chemical equation for the same reaction. What additional information does a balanced chemical equation provide that cannot be obtained from a word equation? Illustrate your answer with a suitable example.
Generated by claude-sonnet-4-6 · 2026-06-26 00:54 · grounding rag
Model Answer
Word Equation vs. Balanced Chemical Equation
A word equation names the reactants and products in words, showing the direction of the reaction. It only tells us what substances are involved.
Example:
Zinc + Sulphuric acid → Zinc sulphate + Hydrogen
A balanced chemical equation uses chemical formulae and coefficients, ensuring the number of atoms of each element is equal on both sides (obeying the Law of Conservation of Mass).
$$\text{Zn} + \text{H}_2\text{SO}_4 \rightarrow \text{ZnSO}_4 + \text{H}_2$$
Additional information provided by a balanced chemical equation:
- Chemical formulae of all reactants and products.
- Relative number of atoms/molecules taking part in the reaction.
- Physical states — (s), (l), (g), (aq) — can be added.
- Reaction conditions (temperature, pressure, catalyst) can be shown above/below the arrow.
- Confirms the Law of Conservation of Mass — atoms are neither created nor destroyed.
Source: Chapter 1, Sections 1.1 and 1.1.2
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Explanation
- Examiners expect a clear comparison (1–2 marks), a named example with both equations (1–2 marks), and at least 3 additional points a balanced equation provides (remaining marks).
- The Zn + H₂SO₄ example is directly from the textbook — always prefer textbook examples.
- Don't forget to mention physical states and reaction conditions as extra information; students often miss these.
- The Law of Conservation of Mass is the reason equations must be balanced — mentioning it earns a mark.