Question

(a) What are the various ways in which a chemical equation can be made more informative ? Give examples to illustrate your answer.

(b) Write balanced chemical equation from the following information :

An aqueous calcium hydroxide solution (lime water) reacts with carbon dioxide gas to produce a solid calcium carbonate precipitate and water

Answer 1

(a) The various ways in which a chemical equation can be made more informative are : (i) By indicating the physical states of the reactants and products. Example: Gaseous state is indicated by the symbol (g).

Zn (s) + H₂SO₄ (aq) —–> ZnSO₄ (aq) + H₂ (g)

(ii) By indicating the heat changes taking place in the reaction. For xxample: An exothermic reaction is indicated by writing “+Heat” or “+Heat energy” or “+Energy” on the products side of an equation. 

C (s) + O₂ (g) —–> CO₂ (g) + Heat

(iii) By indicating the “conditions” under which the reaction takes place. Example: Delta stands for heat which is written over the arrow of the equation.