of the Chemical Sciences Society
National University of Singapore
|Chemiscope, Nov 87|
in the Chemistry Lab
My first practical session was spent familiarising myself with the intricacies of titration. It had been a long time since most of the guys had last fumbled over the apparatus of the chemistry lab and time had not done a thing to improve our skills. Our demonstrators (a masters and an honours student) had perpetual smiles on their faces as they guided us. But soon our memories came to our aid and we managed to become quite proficient or so we thought ...
Fumbling proved to be a basic part of our lives in the chemistry lab and many of us became resigned to the fact that something would happen each time we stepped into the lab. On the rare occasions of a trouble-free run, I have silently contemplated the misadventures of my fellow undergraduates which did much to reassure myself that I was not alone in my misery. The discovery of major mistakes were announced in different ways from silent muttered grumblings of discontent to hysterical laughter or a loud wail which particularly characterised some of my lab partners. Upon reflection, I realised that we have done much to enliven the dreary afternoons of our demonstrators.
Typical scenes in the library were enacted when students from these labs came in to do their reports. When they sat down, the poor unfortunate souls sitting around them started to screw their noses up as the unmistakable waft of organic fumes filled the air. So Chem students-to-be, do take heed of this and keep a bar of soap in your lockers so as to spare your fellow mortals the effort of holding their breaths!
Another effect of this lab was that the girls tend to lose their nail polish to the solvating properties of compounds such as acetone. Of course this was mild compared to the potential hazards in the lab. Such a case was illustrated by a friend of mine who decided to do away with the use of a pipette filler after it refused to function despite a prolonged wrestling bout (many students can attest to this). As he sucked the end of his pipette, the expression on his face told us, the grim story of the intoxicating effects of volatile chloroform! His vigorous coughing made the rest of us around him keep a firm grip on our pipette fillers, reinforcing the effect of the cautioning we had received about lab safety.
Sometimes, we get carried away in our enthusiasm, resulting in more woes! The extraction of a solute from one immiscible solvent to another involves a certain amount of shaking of the separating funnel. Some of us quite happily shook the life out of the funnel which led to quite perplexing results. One inquiry, they discovered that the force of the effort had resulted in complex formation! However, not all students had such complicated problemssome of them couldn't come to grips with the separating funnelthey had problems even holding it properly! More extreme cases involved getting residue off the filter paper. Difficulties arise when it hasn't dried properly yet as one frustrated chap found out. He had scrapped off a fair amount of paper as well as the residue and resorted to centrifuge to separate paper from chemical!
One fact which never failed to astound me was that pairs of students seemed to take a longer time over their experiments than lone individuals. My partner and I were no exceptionperhaps it was due to the fact that he seldom read his lab schedule before coming to the lab. This is termed as living dangerously and as I recalled, was a disastrous practice.
I had to brief him about the experiment while we performed it. This was never foolproof because the concentrations of reagents used in many experiments are of absolute importance, so whenever I failed to give implicit instructions (assuming such things were understood) we would spend ages pondering over the inactivity of the reagents in our test-tubes while that of our neighbour's exhibited exciting colours. I used to feel homicidal when on redoing, he confessed to using the reagent from the bottle labelled 0.01M instead of 1.00M!
My partner (may his soul never rest in peace) once passed me a beaker full of what he claimed to be the base I needed for the titration that I was to perform. It was in fact, acid. So, with a biurette full of what I trustfully thought to be base, I ended up doing an acid-acid titration which is, of course, endless as the indicator never changes. A simple litmus test confirmed my suspicions about the authenticity of the 'acid' in my biurette and put an end to the protestations of my partner (I would love to print his name!) who claimed he would never make such a silly mistake. Faced with the irrefutable evidence, he (quite infuriatingly) started laughing.
Time did nothing to heal our wounds. By the time we reached our last lab series, we felt we were fairly proficient until we sat down for the briefing in our next practical lab. This one lasted much longer than what we were used to and involved highlights of what he felt to be ridiculous scenes exhibited by the previous classes during the term. There were embarrassed faces as culprits realised the striking familiarity of those scenes.
Cases mentioned included the blowing of pipettes to push out every single drop in the spirit of accuracy (that last bit should be left thereit's made that way). Apparently some individual refused to be convinced (perhaps he just forgot) and was heartily blowing away when our esteemed lecturer crept up behind him and grasped his neck, comically questioning his motives! A rude awakening for the disbeliever!
The briefings were rather amusing in a way. For instance, in the midst of a briefing, the fire alarm went off. Our lecturer didn't even blink an eye as he expounded on the correct use of a measuring cylinder while we exchanged quizzical glances as to the origin of the sound. I can still remember his remarks about the student who tried to fill this apparatus with unbelievable accuracy.
"He obviously doesn't know what he is doing!". The measuring cylinder is used for approximation, which means plus or minus a few marks on the scale is of no consequence. However, many students were caught diligently striving for an exact reading on the already inaccurate apparatus with the aid of a water bottle!
Those amongst us who had been guilty of such a misdemeanour carefully made a note to put a stop to the habit as this lecturer has a tendency to stalk around the lab, keeping an eye out for such offenders!
As we recuperated in the canteen after we had finished for the day, we discussed the "bell" we had heard earlier. As our friends from the other labs joined us, we realised that one of the practical classes had actually scampered out of their labs to the ground floor! While we were congratulating ourselves over having avoided a hot afternoons exercise, they went on to tell us how they had actually got their lecturer to treat them to tea before returning to start on their experiments! Hence, over the year, I have come to expect more than just reactions in the chemistry laboratory!
© N Sivasothi, 2001