Chemistry & Environmental Dictionary

Molality - MWC

Molality

is the number of moles of solute dissolved in one kilogram of solvent. Note: be careful not to confuse molality and molarity. Molality is represented by a small "m," whereas molarity is represented by an upper case "M."

Molarity

the number of moles of a solute dissolved in a liter of solvent. Note: be careful not to confuse molality and molarity. Molality is represented by a small "m," whereas molarity is represented by an upper case "M."

Molar Mass

is a unit that enables scientists to calculate the weight of any chemical substance, be it an element or a compound. Molar mass is the sum of all of the atomic masses in a formula. More information and molar mass calculator.

Mole (mol)

is the basic unit of measurement in chemistry. By definition, in modern chemistry, one mole represents the number of carbon atoms in exactly 12 grams of carbon 12 (C12).

Molecule

a complete chemical unit. While a molecule is often thought of as consisting of more than one atom, this is not always true. For instance, helium has only one atom per molecule. The oxygen molecule (O2) contains two atoms, as do chlorine (Cl2), hydrogen (H2) and nitrogen (N2). Some molecules are huge having a molecular weight in the millions. Macromolecules contain literally thousands of atoms. Some macromolecules must remain in tact in order to retain their chemical entity. These are usually proteins. Polymers are chains or networks of repeating sequences of chemical units known as molecules. Examples are polypropylene or cellulose. Molecules of polymers can be broken without destroying the chemical integrity.

Monatomic

elements that are present in the gaseous state as single atoms. These elements are the noble gasses: He, Ne, Ar, Kr, Xe and Rn.

MRF (Municipal Recycle Facility)

Facilities for recycling municipal waste. There are dirty MRFs, which take all garbage as a collective and sort out the recycables at a central facility, and there are clean MRFs that require recycables to be separated out by the generator and are collected separately.

MSW (Municipal Solid Waste)

Includes non-hazardous non-liquid waste generated in households, commercial businesses, light industry and commercial establishments. The exact definition varies from one municipality to another.

MWC (Municipal Waste Combustor)

Are modern waste incinerators that are highly regulated in terms of permissible emissions. They also produce energy either in the form of steam or electricity.

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