Thoughts by Richard Bleil
Happy Mole Day. For those who are unaware, on October 23, from 6:02 AM to 6:02 PM every year we celebrate “Mole Day”. If the specifics of the timing strike you as odd, it was chosen based on Avogadro’s Number, the number of items in one mole, which in scientific notation is 6.02×10^23 (6:02 10/23). In decimal form this is 602,000,000,000,000,000,000,000 or six hundred and two thousand trillion.
Again, this might seem an odd number. Chemists think in terms of moles; it’s really the same as a dozen or a score. A dozen is always 12. A dozen what? Well, a dozen items, whatever those items you are speaking of, just as a score is always 20, and a gross is always a dozen dozen or 144. In water, H2O, we can say there are two hydrogen to one oxygen, but we can also say there are two dozen hydrogen to one dozen oxygen, or two gross of hydrogen to one gross of oxygen. Chemists would say two moles of hydrogen to one mole of oxygen. The problem, of course, is that while we think in terms of moles, we have no device that can actually count individual atoms or molecules. Because of that, we are forced to use mass.
We have scales to measure grams, so we need a way to convert from mass to moles. Avogadro realized that elements all have fixed relative masses. Oxygen is sixteen times heavier than hydrogen, so if we have 2 grams of hydrogen and 16 grams of oxygen, we must have two hydrogen for every oxygen. Here’s an example that might make you feel better. An African elephant weighs, on average, 6,000 lbs (3 tons). Humans, on the other hand, have an average weight of about 140 lbs. So, if we have 60,000 lbs of elephants, and 2,800 lbs of humans, we have 10 elephants (60,000/6,000), and 20 humans (2800/140), or a ratio of 2 humans for every elephant. Avogadro did not know the value of this number, but rather chose a mass easily measured in labs with the technology of his time. Thus, one mole was 1 g of hydrogen, and 16 g of oxygen. Only later did we determine the exact number this is (6.02×10^23), but that really isn’t necessary. If I tell you I need three times more eggs than sausage (mmm…sausage…aauuuuggghhhhh), then three gross of sausage for each gross of eggs will give us the desired ratio.
National Mole Day is an effort by the American Chemical Society to bring increased awareness of chemistry and society, although I usually expand that concept to science in general. The funny thing is that few people actually understand how significant chemistry is to our society. I overheard a biology professor talking about a research project with a student, saying they are measuring phosphate in the lake, but don’t worry, it’s not chemistry. Well, it is. You’re measuring the concentration of a chemical in the environment, that’s analytical chemistry (the career path on which I had begun before heading back to college for my advanced education). In fact, DNA analysis is chemistry, based on gel chromatography developed by chemists. Heck, your whole body is chemistry, from cell membranes to ATP to proteins to ionic concentration. You are a chemical factory designed to convert energy into forms to maintain life.
Near the university where I taught was an ethanol plant. One could argue that this is biology; corn mash was treated with enzymes that broke down the sugars and converted them into alcohol. Sugars and enzymes are biochemistry, and ethanol is organic chemistry. They were hiring two lab techs to assay the percent purity and contamination levels of the product. This is analytical chemistry. So, they were certain that they needed biologists.
They hired one of our biology majors to work in the lab, as well as one of my chemistry students. Starting out the put the biology major (a male, which may or may not have been a factor) at a higher starting position than my chemistry student (a female). One day she came to my office asking advice, because they had offered her (not him) the full-time position, but she would have to drop out of school. I cautioned her that this was a glass-ceiling; the money they offered to her was attractive enough for her to consider it, but she would be stuck in that position forever without completing her degree. That would be fine if she loved it enough that she had no desire to advance, but she chose to stay in school. Today, she is coordinating the lab work for all of the local labs from the corporate headquarters. The biologist, last I heard, is still in that local lab.
Don’t jump to conclusions on what the “correct” science is. In reality, they all work together, each enriching the others, but the most generally applicable science is chemistry. While physics and mathematics are more fundamental sciences (mathematics more fundamental than physics if you wish to know the order), chemistry applies to all matter, that is, the stuff that makes up plants and animals, planets and stars, rocks and soil, and even the computer you are using to read this and the screen illuminating the words.
It’s ALL chemistry.