The Words of Chemistry

There is some truth to the idea that chemistry is a different language. Chemists use words with special scientific meanings and special scientific pronunciations. Ask a scientist to read the words “unionized” or “periodic.” A non-chemist will say the first word as if it meant that a working place had a union. A chemist would say the same work as if a material that could come apart into ions had not separated (un-ionized). A non-chemist would say the second word as if it were something that happened every period of the same time length. If a chemist knew it referred to a compound, you might hear “per – iodic,” as in periodic acid, HIO4 (purr – eye – oh – tic), the acid of the periodate ion, (IO4).

There are a few words that are ALMOST regular English words, but, if you are not looking too carefully, you could miss. Mol (or mole) MOLARITY is a measure of the concentration of a solute in a solvent expressed in units of mols of solute per liter of solution. It ALMOST looks like morality, but it is just not the same. While you are not looking, your word processor could change the molarity to that more common English word and thoroughly embarass you to your chemistry professor with its immorality. Even worse, MOLALITY is another measure of concentration, though not as useful in general chemistry. Molality is mols of solute per liter of SOLVENT.

There are some words that look and sound exactly the same, but mean different things in English and chemistry.

, in English, is the ability to put one’s mind to work. In chemistry, it is the amount of a material in a volume, such as the amount of salt in a salt solution. You would think that honorable chemists would not mess with a good English word like “normality,” but in the scientific world NORMALITY is a concentration measure that is the number of equivalents per liter of solution. And there we have done it again. An EQUIVALENT is a mole of the active part of a material. That needs some explanation. The active part of an acid is the ionizable hydrogen, a hydrogen atom that is likely to be removed from the rest of the comopound to become an H+ (or an (H3O)+ hydronium ion. So hydrochloric acid, HCl, has one ionizable hydrogen and a mole of HCl is one equivalent, but H3PO4, phosphoric acid, has three ionizable hydrogens. One mol of H3PO4 is THREE equivalents of phosphoric acid.

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CONCENTRATION – The amount of a material in a volume, such as the amount of salt in a salt solution. The unit, “molar,” is the most common unit of concentration for solutions. A one molar solution has one mol of the solute per liter of solution.

FREE – Not attached, or not as a part of a compound, as gold atoms in jewelry are the free element.

VALENCE – Likely charge. Sodium (Na) has only one valence. The only likely ion of sodium is the Na+ or sodium plus one ion. Many transition elements, like iron, have more than one valence. Ferric ion, Fe++, has a charge of plus two, while the ferrous ion, Fe+++, has a charge of plus three. Metal elements have positive valences, while non-metal elements have negative valences and gain electrons to have a negative charge.

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