Question

What do the coefficients in a balanced chemical equation represent?

Answer 1

To solve this question we first need to know what is a balanced chemical equation. A balanced chemical equation is a reaction in which the number of atoms in a reaction is equal on both the reactant and the product side for each element.

Complete answer:
A balanced chemical reaction satisfies the law of conservation of matter.
Subscripts and coefficients determine the number of atoms and molecules in a chemical equation.
The part of the chemical formula that shows the ratio of a molecule's atoms and determines its chemical identity are known as subscripts. For example, in carbon dioxide ($C{{O}_{2}}$) there are 2 atoms of oxygen and 1 atom of carbon. Subscripts are not changed while balancing an equation.
The number of molecules of a substance that is utilized or produced in a chemical reaction is indicated by the coefficients.
Let us take an example of the balanced chemical equation of the reaction of combustion of heptane (${{C}_{7}}{{H}_{16}}$).
${{C}_{7}}{{H}_{16}}+11{{O}_{2}}(g)\to 7C{{O}_{2}}+8{{H}_{2}}O$
From the balanced chemical equation we can see that when one mole of heptane (${{C}_{7}}{{H}_{16}}$) is burnt in the air, it combines with 11 moles of oxygen gas (${{O}_{2}}$) to form 7 moles of carbon dioxide ($C{{O}_{2}}$) and 8 moles of water molecules (${{H}_{2}}O$).

Note:
It should be noted that in an unbalanced chemical equation, the stoichiometric coefficients can be balanced using the subscripts of the individual atom.
The product of the stoichiometric coefficient of a molecule and the subscript of the atom in the molecule gives the total number of atoms in the reaction that must be equal in both product and reactant sides.