Tuesday, July 31, 2007

Chemistry is a dark art

Back when I thought it was science

My chemistry professor was a rat-race drop-out, a refugee from a southern California job in an industrial laboratory. He had traded his high-income, high-stress occupation in the big city for a modestly compensated academic post at a rural community college.

“It was a question of whether the smog or the alcohol would kill me first. Or maybe a heart attack in the rush-hour traffic. I decided it wasn't worth it.”

He loved his faculty position, playing the wise old professor to the bright-eyed and generally mystified students. Dr. K shuffled about the school's chem lab in backless carpet slippers, popping outside at intervals for a quick nicotine fix. Wreathed in tobacco smoke, he opined that his last major vice was something he could not give up. He was content with having calmed down and dried out.

One of Dr. K's favorite lab experiments concerned the identification by the students of unknown chemical components in solutions mixed up by the professor. We students husbanded our vials of mystery solution, doling out small amounts for various tests as we strove to sniff out what Dr. K had included in each one. After we identified—or thought we identified—each ion floating around in the solution, we presented our results to the professor, whereupon Dr. K would vanish into the back room where he kept the master list of solutions and their constituents. He would smile with pride at those of us who successfully analyzed our samples and he would smile sympathetically at those whose lab results were works of fiction.

Dr. K smiled at me and noted I had made only one mistake in my identifications. My test solution did not include nitrate ion. The others were correct, but I was mistaken about nitrate. Sorry.

“But I saw the brown ring!”

The professor's unruly eyebrows went up a notch.

“Perhaps you thought you saw a brown ring, but it must have been a false positive. I didn't mix any nitrate ion into your solution.”

I marched back to my work station and sacrificed the dregs of my mystery solution to run the nitrate test again. I acidified the solution with a splash of sulfuric acid and a dash of ferrous sulfate. After heating the solution and letting it cool, I tilted the test tube and carefully poured in some concentrated nitric acid, letting it trickle slowly down the side of the tube so as not to get mixed up with the solution already in the tube. The nitric acid sat atop the solution without combining with it. At the interface between the two liquids I saw the tell-tale brown ring that indicates the presence of nitrate ion in the original solution. Aha!

I returned to the teacher station to present my results to the professor. I was quite pleased with myself.

“See, Dr. K? I have a brown ring. I do have nitrate ion in my solution.”

The chemistry professor tilted his head and put his eye up close to the test tube. I eagerly awaited his concession. A small smile quirked Dr. K's lips.

“That's not a brown ring. It's more of a burnt orange color. That's probably because you have a lot of chloride ion in the original solution, which you did correctly identify. But what you have here is not a positive test for nitrate ion.”

Burnt orange? Burnt orange?

I don't recall saying anything further to the professor, although I suspect my eyes were bulging as I walked mechanically back to my lab station and plopped down on the stool. That was the moment—the split-instant of time—when I first realized that chemistry was one of the dark arts. It was magic. Magic! Not science. It was the end of innocence.

The old alchemists were still running the show, grinning at me through veils of sulfurous fumes.


King Aardvark said...

In fairness, maybe your prof was ahead of the game. Metallic burnt orange is emerging as a popular car colour these days.

That said, I hate chemistry. Horrible stuff.

Mikael said...

For me, I gave up on chemistry since it was too easy. It was like lego to the wonderful world of mathematical free sculpture.

I realized I had to choose when I was accepted into the swedish national team to the ICO, and it collided with the Junior Mathematical Congress. I chose the JMC and now am a research mathematician. (alright ... PhD student. But I'm publishing!!!)

Alex said...

How did you remember the chemicals involved?

Zeno said...

Sorry, Alex, I forgot to mention that I have a brain the size of a planet.

Sorry, again. The real truth is that the experience was burned into my brain. And I do remember things rather well. Although it was nearly 40 years ago, this experiment stayed with me. Also, I admit to checking on-line for "brown ring test" because I was scratching my head over whether it was a test for nitrate ion or sulfate ion. My recall isn't perfect, and the involvement of sulfur compounds confused me a bit, but I had the other details down pat.