The molecular weight of phosphoric acid and its calculation

The Molecular Weight of Phosphoric Acid and Its Calculation

Phosphoric acid (H₃PO₄) is a widely used inorganic acid with applications in agriculture, food processing, and pharmaceuticals. Understanding its molecular weight is essential for various scientific and industrial calculations. This article explores the molecular weight of phosphoric acid and explains how it is determined.

Molecular Formula and Atomic Masses

The molecular formula of phosphoric acid is H₃PO₄, which consists of:

Hydrogen (H): 3 atoms

Phosphorus (P): 1 atom

Oxygen (O): 4 atoms

To calculate the molecular weight, we use the atomic masses of these elements (in atomic mass units, amu):

Hydrogen (H): 1.008 amu

Phosphorus (P): 30.974 amu

Oxygen (O): 16.000 amu

Molecular Weight Calculation

The molecular weight of H₃PO₄ is determined by summing the atomic masses of its constituent elements:

(3×1.008)+(1×30.974)+(4×16.000)(3×1.008)+(1×30.974)+(4×16.000)=3.024+30.974+64.000=3.024+30.974+64.000=97.998amu=97.998amu

Thus, the molecular weight of phosphoric acid is 97.998 g/mol.

Importance of Molecular Weight

The molecular weight of phosphoric acid is crucial in:

Stoichiometric Calculations – Used in chemical reactions to determine reactant and product amounts.

Concentration Measurements – Helps in preparing solutions with precise molar concentrations.

Industrial Applications – Essential for calculating dosages in fertilizers, food additives, and pharmaceuticals.

Conclusion

The molecular weight of phosphoric acid is 97.998 g/mol, calculated based on the atomic masses of hydrogen, phosphorus, and oxygen. This value is fundamental in chemistry and industry, ensuring accurate formulations and processes.