Chapter 11. Pliny (Redox Reactions)


The flower of copper also is useful as a medicine. It is made by fusing copper and then transferring it to other furnaces, where a faster use of the bellows makes the metal give off layers like scales of millet, which are called the flower.

Great use is also made of verdigris. There are several ways of making it; it is scraped from the stone from which copper is smelted, or by drilling holes in white copper and hanging it up in casks over strong vinegar which is stopped with a lid; the verdigris is of much better quality if the same process is performed with scales of copper.

 — Pliny the Elder, Natural History, Book XXXIV, ca. 60 AD[1]


Imagine you're living a hundred thousand years ago. Your best friend, Bob, was just mauled by a lion and he's looking, quite literally, like something the cat dragged in. You want to gussy him up for the afterlife so you dress him up in his best loincloth and stuff him into a hole with his second-favorite spear. He looks so pale, lying there like a mackerel in his Sunday go-to-meeting clothes. So you give him a good dusting with red ochre, that is, powdered iron oxide, and it seems to restore the blush of life. Seventy thousand years later, your palette has expanded to include yellow ochre and charcoal and you can paint the Paleolithic equivalent of the Sistine Chapel on cave walls, enhancing the longevity of your meme-plexes beyond all previous records. By the time of Pliny the Elder you can paint frescos in yellow orpiment (arsenic sulfides), red cinnabar (mercury sulfide), white limestone (calcium carbonate) and gypsum (calcium sulfate), blue malachite and azurite (copper carbonates), and, of course, green verdigris (copper acetate). All of these pigments are compounds of metals. While Chapter 7 taught you to balance reactions in which two compound swap their first and last names, it did not explain how to produce compounds from elements or vice versa. These kinds of reactions, oxidation-reduction (redox) reactions, are the subject of this chapter.

I have to confess that I just don't understand people, especially the non-fictional variety. People will go to any lengths to memorize the most inconsequential things; one of the Author's life ambitions is to memorize every story Dr. Seuss ever wrote. People will spend enormous effort to learn the rules for games, no matter how complicated they may be. And don't get me started on puzzles. Yet when these same skills are to be used for practical ends, people turn into self-confessed imbeciles. "I don't have a head for math." "I can't do science." A relatively simple set of rules for balancing chemical equations might allow you to understand the chemistry of gunpowder; it seems to me that that would be incentive enough. But as I said, I don't understand people.

The Author assures me that people will go to any lengths to avoid learning something useful. A few years ago he taught a course for pre-med students boning up for the big test which would determine whether or not they would get into medical school. Pre-medical students are a motivated bunch. They will pay extra to go to a college with a good record on medical school applications. They will take the "hard" courses that most students avoid like shrimp-and-bubble-gum salad. They will even pay hundreds of dollars to take a class to prepare them for the test which will decide whether their dream of becoming a doctor will be flushed down the academic toilet. Now, part of the test is a block of questions which depend on the student's ability to balance oxidation-reduction reactions, so the Author made up a handout explaining in detail the easiest method for doing this. He went through some examples and then gave them a sample test on which he allowed them to use the handout. As he gazed out upon the earnest faces, he noticed that not one was using the handout. Obviously they had already learned the method. But when they graded this practice test, would you believe it? Not a single one of those students got even a single correct answer!

So the Author has instructed me to tell you that this chapter provides no useful information of any kind. It will not allow you to understand gunpowder, batteries, photography, fertilizer, pharmaceuticals or plastic. It's just a pointless game. It has some rules, as any game does. Learn the rules and you can play the game. You win the game by getting the same number of each letter of the alphabet on either side of an equal sign. You can play it anywhere with only a pencil and paper. You can play it alone or turn it into a race between individuals or teams. It's fun and challenging, will allow you to impress those of the opposite sex and awe your friends and neighbors. But keep in mind at all times that it is nothing more than a silly game.



Reference [23].