What coefficient is assumed if no coefficient

written before a formula in a chemical equation

1

Explanation:

Consider the following reaction:

Phosphorus burn in the presence of air and produced diphosphorus pentoxide.

Chemical equation:

P₄ + O₂ → P₂O₅

Balanced chemical equation:

P₄ + 5O₂ → 2P₂O₅

Equation is balanced because there are four phosphorus atoms ans ten oxygen atoms in both side of equation.

Coefficient with reactant and product:

P₄ 1

O₂ 5

P₂O₅ 2

There is no coefficient written before P₄ it means only one P₄ is present.