what is the difference between "low molecular weight" and "high molecular weight" ?

Answer 1

Low molecular weight and High molecular weight refer to different "Sizes" of a molecule. Usually used in terms of polymers, where low molecular weight would be a small polymer made of fewer monomer units and a high one one be made of many times more units. Thus the bigger polymer would weigh more. The same idea applies to proteins, high molecular weight protein is a big protein made of many amino acids (c.a. >100,000 Da), a small one is made up of less (c.a. <40,000) amino acids.

If you are looking for a numerical cutoff where something can steadfast be called small or large I don't know if such a number exists.

Answer 2

Low molecular weight means that the compound has a small molar mass. For example, water has a low molecular weight. One mole has a mass of only 18 grams. Now compare that to a protein, which has a high molecular weight. One mole of a protein can be thousands of grams.

Answer 3

Quick Answer: The Molecular weight of a molecule is the sum of the atomic weights of the atoms of that molecule, OR the weight of 1 Mole of that molecule (6.03E23).

Every substance is made up of combinations of molecules. Sometimes it is one molecule repeated over and over, sometimes it is a mixture of many molecules.

Water, for instance is made up of many many molecules of H2O, thats two hydrogen atoms bound to an oxygen atom.

Atoms are the buildingblocks for molecules, and are considered to be the basic elements of matter. They can be broken up though, and each atom is made from a core of protons and neutrons surrounded by one or more electrons. In the typical atom there is always as many electrons as there are protons. Protons have a positive charge, and electrons a negative charge. Neutrons are neutral. Protons have a weight of 1, as do neutrons, electrons are so small that their weight is neglible.

An atom has a certain atomic weight, that depends on the number of protons and neutrons it contains. Hydrogen has a weight of 1 (1 proton + 0 Neutrons), Helium a weight of 4 (2 Protons + 2 Neutrons)... and on and on. These weights can be found on the Periodic Table of Elements.

Since Molecules are made of Atoms, they also have a weight, which we call Molecular weight. The Molecular weight is simply the sum of all the atomic weights of the atoms that make up the molecule.

So, for instance, Oxygen has a weight of 16 (8 protons + 8 neutrons) and there are two Hydrogen atoms each having an atomic weight of 1, so thats 2. So, the atomic weight of Water, or H2O would then be 18.

Note: Atomic weight is derivitave of the weight in grams that 1 mole of an element weighs. A mole is 6.03 x 10^23. Molecular weight can then be derived from the weight in grams of a molecule, as that is derivitave of the atomic weight of the atoms within the molecule.

Note: The weights I have listed are a very close approximation, and ones that most people use, check the Periodic Table for the exact weights.


Tiger Striped Dog MD.

Answer 4

high molecular weight means, or course, "big molecular weight"

that means a big molecule

the terms (high molecular weight and low molecular weight) are commonly used in polymers

a polymer (like polyethylene, or PVC) is a long chain molecule, with the chain usually being a string of carbon atoms with other stuff (like hydrogen) attached. a polymer molecule can be many thousands of atoms long

the high molecular weight plastics have longer molecules
they normally melt at a higher temperature and are stiffer and stronger
the lower molecular weight plastics melt easier, flow better, and are often used for injection molding

Answer 5

the mass of the atoms that make up the molecule. something like a DNA molecule with a mass of thousands of grams per mole would have a very high molecular weight, but something like H2 with a molar mass of 2 g would be extremely low.

Answer 6

20 KILOGRAMS PER MOL??? that is insane!. Low molecular weight compounds are mainly monomers, like alkenes or alkynes. High molecular weight means polymers like plastic.

Answer 7

low molecular weight (MW) weighs less than high molecular weight. low MW could mean small molecules, whereas high MW could mean polymers, which could be millions of g/mol in a single molecule. one practical typical physical difference is higher viscosity with high MW. the line between high and low MW is arbitrary drawn at about 20kg/mol.

Answer 8

The constituent elemental configuration of the molecular group?

Answer 9

you inspired me to ask a question about the mile high club. I have yet to join this 'club' seeing that I haven't been on a plane in 30+ years

Answer 10

high is up here and low is down there. next question!