Formula Mass
| Formula / Notation | Formula mass = sum(atomic masses × subscripts) in chemical formula |
|---|---|
| Also Known As | Formula weight, molar mass, molecular weight (for molecular compounds), relative formula mass |
What is Formula Mass?
The sum of the atomic masses of all atoms in a chemical formula. For ionic compounds, it is called the formula mass rather than molecular mass. For example, the formula mass of NaCl is 23 + 35.5 = 58.5 g/mol. Used in stoichiometric calculations.
Formula & Notation
Other Names / Synonyms: Formula weight, molar mass, molecular weight (for molecular compounds), relative formula mass
Properties & Characteristics
Uses & Applications
Safety Information
Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.
Key Facts
Frequently Asked Questions
The sum of the atomic masses of all atoms in a chemical formula. For ionic compounds, it is called the formula mass rather than molecular mass. For example, the formula mass of NaCl is 23 + 35.5 = 58.5 g/mol. Used in stoichiometric calculations.
Formula mass calculations are the basis of all stoichiometric calculations: converting between moles and grams (n = m/M), preparing solutions of known molarity (M = n/V), and determining empirical vs. molecular formula relationships.
No direct safety concern. Errors in formula mass calculation lead to wrong amounts of reagents and potentially hazardous experimental conditions (too much reactive chemical, wrong concentration of dangerous solution).
The formula or notation for Formula Mass is: Formula mass = sum(atomic masses × subscripts) in chemical formula