# Molecular Weight

Written by Jerry Ratzlaff on . Posted in Thermodynamics

Molecular weight, abbreviated as MW, also called molecular mass, refers to the average mass of one molecule of a substance, 1⁄12 (0.083) the mass of carbon 12 atom.

## Molecular weight formula

 $$\large{ MW = \frac{ R^* }{ R } }$$

### Where:

 Units English Metric $$\large{ MW }$$ = molecular weight $$\large{\frac{lbm}{lbmol}}$$ $$\large{\frac{kg}{kmol}}$$ $$\large{ R }$$ = specific gas constant $$\large{\frac{ft-lbf}{lbm-R}}$$ $$\large{\frac{J}{kg-K}}$$ $$\large{ R^* }$$ = universal gas constant $$\large{ \frac{lbf-ft}{lbmol-R} }$$ $$\large{ \frac{J}{kmol-K} }$$

Tags: Weight Equations