Question

What is meant by the term ‘chemical equation’? What are the essentials of a chemical equation?

Answer 1

Chemical equation:

• A chemical equation is a brief representation of a chemical change in terms of symbols and formulae.
• The substances which react among themselves to bring about the chemical change are known as reactants, whereas the substances which are produced as a result of the chemical change are known as products.

For example:

$$\begin{gathered} 2{\mathrm{KClO}}_{3\left(\mathrm{s}\right)}\stackrel{∆}{\to }2{\mathrm{KCl}}_{\left(\mathrm{s}\right)}+3{\mathrm{O}}_{2\left(\mathrm{g}\right)} \\ \mathrm{Potassium}\mathrm{Potassium}\mathrm{Oxygen} \\ \mathrm{chlorate}\mathrm{chloride} \end{gathered}$$

Principles involved in writing chemical equations:

• A chemical equation must represent a true chemical change.
• The reactants are always placed on left-hand hand side.
• The formulae of various reactants are separated by plus (+) sign.
• The products are placed on the right-hand side.
• The formulae of products are separated by plus (+) sign.
• The reactants and products are separated by an arrow ($\to$) pointing towards the products or the sign of equality (=) which means to produce.
• It should be balanced that is the total number of atoms of each kind on both sides of the arrow must be equal.
• Chemical reaction should be molecular.