Saturday, 28 February 2009

S205: TMA-3

Time for TMA-3 - and a bit of a disaster for me, despite thinking I'd done it almost perfectly!

Question 1 was about molecular orbital theory, and drawing diagrams and putting electrons in for a molecule of PS. Most of this was fairly easy, except for the last part where you had to work out how it would decompose. Despite questioning my tutor, I couldn't grasp exactly what this was asking, and got almost no marks for this part. I'm still not much the wiser.

Question 2 concerned semiconductors and the doping thereof. Some more diagrams to be drawn and some theory to be expounded on.

Question 3 was about organic reactions, and mostly to do with carbocations and yet more stereo-chemistry. I don't think I have the patience to do some of these reactions, and it shows in the marks I get! Some of the latter part of the question was on synthesis techniques, and how to get from one compound to another.

Question 4 was full on synthesis. How to move around from one molecule to the next, what sort of thing you needed to add to it, and what conditions this might happen under and so on and so forth. I think I did ok on this one, but it was a struggle.

This TMA is probably the low point so far for me, as I didn't do nearly as well as I thought I would, and it sort of leaves you wondering if you understand the basics or maybe you're just not cut out for the subject. However this seems to happen in most of the 60 point courses I've done, so its probably just a psychological hump. I hope so!

Wednesday, 25 February 2009

S283: Book 1 - An Introduction to the Solar System

Book 1 is a fairly weighty tomb, but about the size of the S282 books, and similar to the 2nd book in the course as it happens. Its 412 pages in total, and split into 9 chapters.

Chapter 1 is an introduction to the solar system. We briefly visit all the major bodies of the solar system in turn and look at the general layout of things. It gets you oriented into whats where and what will be looked at in the next few pages.

Chapter 2 looks at terrestrial type planets and their internal structure. There is a fair smattering of geology in this part, and stuff about tectonics and inner cores and stuff like that. There is also some parts on what happened over its life as the rocks were 'cooked' and changed.

Chapter 3 looks in depth at volcanism. So there is a lot about volcanoes and eruptions of lavas and what that can do to surfaces. It also considers cryovolcanism, where water and ice errupt in the more frozen worlds giving similar results.

Chapter 4 looks at planetary surfaces and in particular at cratering and what it can tell us about what has happened. We go into quite a lot of depth (NPI) on different types of crater and how they can be recognised.

Chapter 5 looks at plaentary atmospheres - for those lucky enoguh to have them. It also looks at clouds, and atmospheric motion, and the different layers that they tend to split into.

Chapter 6 looks at the gas giants, and what they're structure might be.

Chapter 7 is concerned with the more minor bodies of the solar system. So things like asteroids, comets, the Kuiper belt and even interplanetary dust.

Chapter 8 looks at how the solar system was formed, and what that was all about.

Chapter 9 ends up looking at meteorites and what they can tell us about what happened at various stages in its evolution.

So - that was quite a tour, but in some ways it wasn't as detailed as the earlier planets course I did. Many of the mechanisms we gone into in a lot more depth, but I didn't come out of it feeling I knew a lot more about the planets, but knowing a fair bit more about their formation.

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Monday, 23 February 2009

S205: Book 8 - Separation, purity and Identification

Book 8 - and quite a thin one for a change. However the euphoria of that swiftly departs towards the end. Anyway, the first part is all about practical chemistry, something we don't do any of in this course, other than read about it!
We have some chapters on separation of products, by using suitable dissolving agents and the like goes with like rule. Then there is a chapter on how to find out how pure the substance you made is, and then some stuff about identifying the compound you've made.

Then, just as you think the book is about finished, we move onto IR spectroscopy and NMR. There is nothing written about this in the book, other than directions to work through a whole set of videos and computer aided learning on the accompanying DVD.

So there are a number of exercises to work through to find out what NMR and IR are telling you about things. After working through IR and getting the idea you can find some stuff out, the NMR comes as much more of a revelation as it gives you much more information in general.

Finally the book ends up with a case study on forensic science and what chemists can do to aid the search for truth.

Friday, 6 February 2009

S205: Book 7 - Alkenes and aromatics

Book 7 - and its more organic chemistry. This time is starts by looking at addition reactions. That is part 1 of this book, and doesn't have anything fantastically earth shattering as we've been looking at similar sort of mechanisms for a while
Part 2 goes on to look at aromatics, benzene rings and stuff like that. In particular Freidel-Craft reactions which show you ways of sticking stuff onto these rings. Its all a bit complex as there are all sorts of ways of adding stuff in depending on where you want it to add up, but by the end you can sort of see how some of the ideas of synthesis come about.
Then it is part 3, which is solely about synthesis, and ways of getting from a starting compound to where you want to end up. Its one of those topics that I can follow along, but would be completely lost if asked how you go about synthesising something new.
Finally the book ends up with a case study looking at petrochemicals and what sort of separation and other techniques are useful there.