A2 Chemistry practical
May. 26th, 2005 04:00 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
ravenI did it! I held myself together long enough to do it. For reasons that are too complicated to interestingly explain, I arrived at school before eight in the morning and had to go round the library opening doors and switching on lights. And then I waited, while the others came in and the light rose through the windows, and finally nabbed a labcoat from one of the biology labs and took myself upstairs to hurry up and wait some more.
They let us in, and then there was a gradual ripple of laughter as we all took in the apparatus on the benches. Test-tubes and bottles, nothing more. In short, our A2 practical was exactly the same as last year's. Well, not in every particular; this year we had to do two of the ions tests in a water bath, but even that wasn't painful. Usually it involves fussing with Bunsen burners, but the technicians had just taken two kettles from Home Ec and left them on the boil. I did it slowly, without making the same mistakes as I did last year, and finished off neatly and nicely with ten minutes to spare.
The analysis/evaluation was an equilibrium calculation using the classic esterification reaction, ethanol and ethanoic acid. It had the potential to be a bit tricky, but they actually stated what was wrong with it - namely, that the the amount of alkali used to determine the equilibrium conc of acid was too small. How would you resolve this, they said. And then they wanted you to give the Kc value for the reaction. In short, it was easy.
That said, I may have come unstuck on the plan. Even so, it was easy too - a straightforward redox of peroxide and manganate(VII). Find the original conc of the peroxide, allowing for dilution and a standard solution of manganate, and give how you would calculate. I decided, arbitrarily, that the titre value should be 42 (well, why not?) and used it to show the entire calaculation.
The exam ended at eleven, at which point Mrs Colvin said, "I think you can talk now..."
There was an immediate hubbub. No-one can believe it was the same as last year. And, as I said with some asperity, "We did all those hundreds of titrations for nothing!"
And, of course, that I shall never do a practical again. I took off my labcoat and was sorry to see it drop to the table. So, the general consensus is that it the whole exam was fine. On my way back to the library, Mrs Miller stopped me and gave me an unexpected gift.
She gave us all a print of this pic. It was taken last week, on Wednesday when we were banoffee pie taste-testing, and I really love it and am planning to hang on to it carefully. It's all seven chemgeeks - from left, Becky O, Fidan, Laura, me, Rola, Sarah and Steph. I showed it to Mrs Barry later, who said, thoughtfully, "You look ready to go, all of you."
I suppose we do. It could have been taken in a university lab rather than a school one, she said as well, and no-one would know it. I think I agree with her.
And, for good measure:
It's come out a bit strange, but I still like it. On the top, from left, Rola, Mrs Miller, Steph, Mrs Colvin, Fidan, Becky O, and on the front are Sarah, Laura and me, along with a giant model of the macromolecular structure of silicon dioxide. I think.
I returned the labcoat to the biology lab with a lingering sense of regret. No more practicals, ever. It's probably going to take a while to sink in.
Anyway, I now have no more exams until June 15th. I think I'll take the rest of the day off.
They let us in, and then there was a gradual ripple of laughter as we all took in the apparatus on the benches. Test-tubes and bottles, nothing more. In short, our A2 practical was exactly the same as last year's. Well, not in every particular; this year we had to do two of the ions tests in a water bath, but even that wasn't painful. Usually it involves fussing with Bunsen burners, but the technicians had just taken two kettles from Home Ec and left them on the boil. I did it slowly, without making the same mistakes as I did last year, and finished off neatly and nicely with ten minutes to spare.
The analysis/evaluation was an equilibrium calculation using the classic esterification reaction, ethanol and ethanoic acid. It had the potential to be a bit tricky, but they actually stated what was wrong with it - namely, that the the amount of alkali used to determine the equilibrium conc of acid was too small. How would you resolve this, they said. And then they wanted you to give the Kc value for the reaction. In short, it was easy.
That said, I may have come unstuck on the plan. Even so, it was easy too - a straightforward redox of peroxide and manganate(VII). Find the original conc of the peroxide, allowing for dilution and a standard solution of manganate, and give how you would calculate. I decided, arbitrarily, that the titre value should be 42 (well, why not?) and used it to show the entire calaculation.
The exam ended at eleven, at which point Mrs Colvin said, "I think you can talk now..."
There was an immediate hubbub. No-one can believe it was the same as last year. And, as I said with some asperity, "We did all those hundreds of titrations for nothing!"
And, of course, that I shall never do a practical again. I took off my labcoat and was sorry to see it drop to the table. So, the general consensus is that it the whole exam was fine. On my way back to the library, Mrs Miller stopped me and gave me an unexpected gift.
She gave us all a print of this pic. It was taken last week, on Wednesday when we were banoffee pie taste-testing, and I really love it and am planning to hang on to it carefully. It's all seven chemgeeks - from left, Becky O, Fidan, Laura, me, Rola, Sarah and Steph. I showed it to Mrs Barry later, who said, thoughtfully, "You look ready to go, all of you."
I suppose we do. It could have been taken in a university lab rather than a school one, she said as well, and no-one would know it. I think I agree with her.
And, for good measure:
It's come out a bit strange, but I still like it. On the top, from left, Rola, Mrs Miller, Steph, Mrs Colvin, Fidan, Becky O, and on the front are Sarah, Laura and me, along with a giant model of the macromolecular structure of silicon dioxide. I think.
I returned the labcoat to the biology lab with a lingering sense of regret. No more practicals, ever. It's probably going to take a while to sink in.
Anyway, I now have no more exams until June 15th. I think I'll take the rest of the day off.
