State five ways by which a chemical equation can be made more informative.

A chemical equation can be made more informative 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 beside the symbols for the reactants and products.
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 (→) separating the reactants and products.
4. Concentration of reactants and products are indicated by adding the words (dil.) for dilute and (conc.) for concentrated before their formulae.
5. By using the sign → and ⇌, information about irreversible and reversible reactions can be depicted.