Q1. [2] straightforward initial-understanding
In a balanced chemical equation, state symbols are used alongside the formulae of substances. What do the symbols (s), (l), (g), and (aq) represent? Why is it important to include these symbols in a chemical equation?
Generated by claude-sonnet-4-6 · 2026-06-26 00:53 · grounding rag
Model Answer
The state symbols represent the physical states of substances in a reaction:
- (s) – solid
- (l) – liquid
- (g) – gaseous
- (aq) – aqueous (substance dissolved in water)
Including these symbols makes a chemical equation more informative by showing the physical state of each reactant and product, giving a complete picture of the reaction.
Source: Chapter 1, Section 1.1.2 (Step VII – Writing Symbols of Physical States)
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Explanation
- Examiners expect all four symbols defined clearly — losing even one definition can cost half a mark.
- The second part (why important) is often missed; the key phrase from the textbook is "more informative" — state symbols tell us how each substance is present in the reaction.
- Remember: (aq) specifically means dissolved in water, not just any solution.