molecular weight

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noun Chemistry.

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.

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Also called formula weight.

Origin of molecular weight

First recorded in 1875–80

Words nearby molecular weight

molecular rotation, molecular sieve, molecular spectrum, molecular surgery, molecular volume, molecular weight, molecule, mole drain, mole fraction, molehill, mole mapping

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022

How to use molecular weight in a sentence

A lot of people ring in the New Year with vows to lose weight and exercise.
How Skinny Is Too Skinny? Israel Bans ‘Underweight’ Models|Carrie Arnold|January 8, 2015|DAILY BEAST
Yet we keep doing the cleanses, buying the meal replacement bars, and joining Weight Watchers.
Why Your New Year’s Diet Will Fail|Carrie Arnold|December 30, 2014|DAILY BEAST
The problem, says UC Davis physiologist and nutritionist Linda Bacon, is that very few people can lose weight and keep it off.
Why Your New Year’s Diet Will Fail|Carrie Arnold|December 30, 2014|DAILY BEAST
Then the commercial weight loss behemoths Weight Watchers and Jenny Craig joined this crowded field.
Why Your New Year’s Diet Will Fail|Carrie Arnold|December 30, 2014|DAILY BEAST

The rule of law, you see, buckles, bends and sometimes crumbles under the weight of racism, sexism, and classism.
What Would Happen if I Got in White Cop’s Face?|Goldie Taylor|December 30, 2014|DAILY BEAST
Of course, considerations of weight have to be taken into account, but the more mould round the roots the better.
How to Know the Ferns|S. Leonard Bastin
Results are in terms of bulk of precipitate, which must not be confused with percentage by weight.
A Manual of Clinical Diagnosis|James Campbell Todd
The weight percentage can be found by referring to Purdy's tables, given later.
A Manual of Clinical Diagnosis|James Campbell Todd
But for the most part even industry and endowment were powerless against the inertia of custom and the dead-weight of environment.
The Unsolved Riddle of Social Justice|Stephen Leacock
All the eight planets added together only make one-seven-hundredth part of his weight.
God and my Neighbour|Robert Blatchford

British Dictionary definitions for molecular weight

molecular weight

noun

the former name for relative molecular mass

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for molecular weight

molecular weight

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

Scientific definitions for molecular weight

molecular weight

The sum of the atomic weights of the atoms contained in a molecule. Also called relative molecular mass

Cultural definitions for molecular weight

molecular weight

[ (muh-lek-yuh-luhr) ]

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