1. The basic building block of the chemical world is the element. Chlorine is an "element" in its pure form. Not much in nature is found in elemental form; gold, lead, oxygen, and mercury happen to be a few of the exceptions. Chlorine is not an exception; it's never found in nature in the pure, elemental form. It's always found in one of many compounds. Salt and bleach are a couple of examples of chlorine compounds.
2. What are "compounds"? They are chemical combinations of elements (or other compounds) that form other materials, that is, definable chemical products that don't look anything like the stuff we started with. Sodium, a nasty element, and chlorine, another even nastier element, form something very different when combined form common table salt – a compound we cannot live without. We can't taste the sodium or the chlorine, thank goodness, just salt. (And what would a hard-boiled egg or fried chicken taste like without it!) All the safe-to-handle, hardware-store "chlorine" products are actually compounds containing chlorine, not the element chlorine itself.
3. What about "mixtures?" Just like blending milk and eggs, a mixture generally has the constituents still separately identifiable. (You can still taste both the milk and the eggs.) Don't get compounds mixed up with mixtures. Air, for example, is essentially a mixture of gasses, most of them existing still as elements. Pure water, on the other hand, is a compound of two elements, hydrogen and oxygen. H2O, as most of us know, stands for water in chemical talk – showing two atoms of hydrogen and one of oxygen. Don't ask about atoms. AFOs are exempt from knowing about atoms.
4. More on water: Water has much more than water in it, by the way. It is a complex solution of mixtures and compounds. (Solution simply means dissolved together.) We can't taste the calcium in water, for example, but we can taste an excess of salt – and in the old swimming hole, maybe even the polywogs! Some of the materials that have been added (by nature or by AFOs) end up only mixing, some end up compounding into other chemicals altogether, and some even ionize.
5. Ionize? Another chemical form to learn? Well, yeah, but this is the last one, we promise. This is a phenomenon that happens often in water, and not so often elsewhere in nature. An "ion" is a part of a compound, temporarily broken away from its other half. It floats out there by itself, usually having an electrical charge making it pretty attractive to other ions. (If this all sounds like the singles scene at a bar or the town's meeting place, I suppose it is a fair analogy...) For example a hydrogen ion is an extra H+, broken off of the H2O, floating around freely in the water. It eventually will re-combine as water or end up as part of another compound altogether. There's only a few other ions we'll be interested in, most of them dealing with chlorine. That's for later.
Prep School Basics :: Chlorine Chemistry |
