M

Molecular Formula

Quick Reference
Also Known AsTrue formula, molecular composition formula, empirical formula (related but different)

What is Molecular Formula?

A chemical formula showing the actual number of atoms of each element in one molecule of a compound, without indicating structure. For example, glucose is C₆H₁₂O₆. The molecular formula can be derived from the empirical formula and the molar mass of the compound.

Properties & Characteristics

The molecular formula gives the actual number of atoms of each element present in one molecule of a compound. It is a whole-number multiple of the empirical formula: molecular formula = n × empirical formula, where n = molar mass / empirical formula mass. For example, glucose: empirical formula CH₂O (EFM = 30), molecular formula C₆H₁₂O₆ (MM = 180, n = 6). The molecular formula gives complete elemental composition but does not indicate how atoms are connected (structural formula does).

Uses & Applications

Molecular formulas are used in: writing balanced chemical equations, calculating molar mass, identifying compounds by high-resolution mass spectrometry (exact mass), and as a starting point for structural elucidation. IUPAC systematic nomenclature is derived from the molecular formula connectivity.

Safety Information

Molecular formula alone does not reveal hazard — ethanol (C₂H₆O) and dimethyl ether (C₂H₆O) are structural isomers with the same molecular formula but very different properties. Always identify the specific structure, not just the formula, before making safety assessments.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Molecular Formula
Synonyms True formula, molecular composition formula, empirical formula (related but different)

Frequently Asked Questions

A chemical formula showing the actual number of atoms of each element in one molecule of a compound, without indicating structure. For example, glucose is C₆H₁₂O₆. The molecular formula can be derived from the empirical formula and the molar mass of the compound.

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