Name That Chemical!

Betcha you didn’t know you had signed up for a foreign language. We need to (at least) look at classifying and naming this humongous mess of stuff we call matter. Again, we’re looking at an almost infinite number of items.

To begin with, chemicals are either organic or inorganic. Generally, chemical compounds containing carbon are organic, all others are classified as inorganic. Unfortunately, this is not universal (Sounds like French? Told you this is not easy!). Let’s start with simple stuff: Binary (just two elements): Something like, oh, table salt. Sodium and chlorine. The first listed, the so-called metal, (sodium) is listed first, as is. The second (nonmetal), chlorine, has its second syllable changed to -ide. Chloride. Thus: Sodium chloride. Formula: NaCl. Thought sodium began with “S”? Well, the element symbol is derived from the latin name Natrium. So are a lot of the others (told you this wasn’t easy…………..).

To look at another common binary compound, how about one consisting of hydrogen and oxygen, Hydrogen is to the left of oxygen on the Table, so it’s listed first. Oxygen undergoes a name change to oxide. Hydrogen oxide. Since these two can form more than one compound, this needs to be addressed. H₂O is thus dihydrogen oxide. NOBODY calls it that! We know it as Water. Hydrogen and oxygen can form another compound where 2 atoms of hydrogen combine with 2 atoms of oxygen. This is called hydrogen peroxide.

Back in high school, or freshman chemistry, you probably were told that this illustrated the Law of Multiple Proportions. Then again, they shot another principle at you called the Law of Definite Proportions. Seem like an oxymoron? Simply, whole atoms form compounds with different numbers of whole atoms, depending on conditions.

The subject of nomenclature is further complicated by a large variety of common chemicals called by “trivial” names. Like water, you have a scientific, systematic name that nobody uses. A compound containing an atom of nitrogen bonded with 3 atoms of hydrogen would be nitrogen trihydride. The rest of civilization calls it ammonia. Just like a language!

Names follow from formulas, so we need to look at this. In its simplest form, a formula tells which atoms are present, and in what ratios. For instance, CO₂ is a compound containing an atom of carbon bonded to two oxygens. CO, carbon monoxide.

is one containing equal numbers of carbon and oxygen. Note the prefixes of oxygen: mono (1) and di (2). Tri means 3; tetra 4, penta 5, hexa 6, ad nauseum.

Consider the compound with the formula KNO₃. K is the symbol for potassium (Latin name, Kalium). As you can see, the stuff also contains nitrogen and oxygen. “NO₃” Turns out this is part of a group of compounds known as “acids”, in this case, nitric acid, formula HNO₃. Acids dissolve in water to produce hydrogen ion and the rest of the molecule, an anion, with the name “nitrate”. KNO₃ is thus dubbed potassium nitrate. Sorry you asked yet?

I could go on, but as you can see, eyes tend to glaze over. When I was an undergraduate at CCNY, I took elementary physics with an old frenchman who taught with a French accent in a whispered monotone. If you asked too many questions, you were invited to “drop de course”. After a few weeks, I took him up on the offer.