molecular weight

noun, Chemistry
1.
the average weight of a molecule of an element or compound measured in units once based on the weight of one hydrogen atom taken as the standard or on 1/16 (0.0625) the weight of an oxygen atom, but after 1961 based on 1/12 (0.083) the weight of the carbon-12 atom; the sum of the atomic weights of all the atoms in a molecule.
Abbreviation: mol. wt.
Also called formula weight.
Origin
1875-80
Examples from the web for molecular weight
  • The first instrument separates all the components of the mixture and the other measures the molecular weight of each.
  • We also wanted to understand how the molecular weight changed as a function of our salt concentration.
  • Natural gas forms when the temperature is higher, favoring lighter molecular weight alkanes.
  • One compound is of low molecular weight and another of high molecular weight.
British Dictionary definitions for molecular weight

molecular weight

noun
1.
the former name for relative molecular mass
molecular weight in Medicine

molecular weight n.
Abbr. mol wt, MW
The sum of the atomic weights of all the atoms in a molecule. Also called formula weight.

molecular weight in Science
molecular weight  
The sum of the atomic weights of the atoms contained in a molecule. Also called relative molecular mass.
molecular weight in Culture
molecular weight [(muh-lek-yuh-luhr)]

The sum of the atomic weights of all the atoms in a molecule.