A chemical equation can give more informations in the following ways:
1. The physical state of the reactants and products can be indicated by putting (s) for solid, (l) for
liquid, (g) for gas and (aq) for aqueous state.
2. Evolution or absorption of heat during the reaction can be denoted by adding or subtracting a
heat term on the product side.
3. Temperature, pressure and catalyst can be indicated above the arrow (→ or =) separating the
reactants and products.
4. Concentration of reactants and products are indicated by adding word (dil) for dilute and (cone)
for concentrated before their formulae.5. By the sign → or
information about irreversible and reversible reactions can be obtained.