Thursday, 17 December 2009

S366: Evolution - arrival

Well guess what arrived just now! I checked the site only yesterday, and it said it wasn't scheduled to start being delivered until next month, but here it is - and a heavy box full it is too!

So - what do you get in this box?
  • Text book - Evolution by Futuyma - which accounts for most of the weight!
  • A companion book to the text book
  • A bookmark with some handy diagrams on
  • An introduction and guide to the course
  • A practical booklet
  • A TMA form - hoping these are eTMAs.
  • A DVD pack
  • Checklist and Welcome note
Its quite a tome is old Futuyma, I don't know how much of it we'll have to read!
Anyway - something to do over the holidays, as if Christmas, kids parties and stuff weren't enough.

Monday, 30 November 2009

S377: Molecular and Cell Biology - Arrival

The next course arrives - it doesn't start until February, but I'm doing two courses together, so I'm glad of the head start. This is only the first of two mailings, but has some good stuff in it.
What you get is:
  • Book 1 - From molecule to cell
  • Book 2 - The Dynamic Cell (Vol 1)
  • A Bookmark with some useful data about amino acids on
  • A ring binder
  • A ring binder insert with pretty picture and title
  • A set of folder dividers
  • A glossary
  • An introduction and guide
  • A study skills pack for books 1 and 2
  • A DVD containing molecular modelling programs, movies and other bits
Notable by their absence is a calendar, TMAs and the normal OU computer disk.
All looks nice and shiny, and I'm ready to go having not had any assignments to do for the last month or so. However as the course site doesn't open for a while yet, there are no assignments to contemplate, just books to read and exercises to do.

Thursday, 22 October 2009

S283: The Exam

It has to be done - another exam. Why do we go through this I wonder?
Well I'll tell you - well actually, I'll tell you why I think its good to do an exam.
  • This is where the course really comes together. There is no avoiding it, you have to confront your weaknesses. You can't go back to the books in the exam and reread a subject and go "Oh yes, I must have skipped that the first time around". I find a lot of things become clearer when you have to be prepared to answer questions on it.
  • You feel validated. I have this nagging feeling that others may be able to do the course, just by reading from the books and repeating stuff without understanding it. I expect this is not true, but if so - well you can't do that in exams. So though its stressful, you feel having done it you understand the subject.
  • For those few weeks of revision - you are a real expert on the material. Sadly it fades sooner or later after the exam, but for a while, should someone make the mistake of asking you a simple question on the topic, they'll find themselves pinned to the wall for an hour or more as you hold forth.
What I don't like about exams is:
  • Memory stuff. In this exam for instance, you really need to know the distance of the planets in AU for the exam. That's just wrote memory test, not much more.
  • That feeling when you open the paper, read a question, and realise you don't know anything about this.
  • All that revision
Anyway - this exam consists of
Part A - 8 multiple choice questions
  • Q1 is about Venus, how far is it from the sun and whats in it atmosphere
  • Q2 is about the structure of planetary bodies
  • Q3 is about the structure of an unidentified planet.
  • Q4 is about the orbit of an asteroid, and needs some of Keplers laws.
  • Q5 is about the requirements for life.
  • Q6 is about Titan and its environment
  • Q7 is about Doppler spectroscopy for detecting exoplanets.
  • Q8 is a graph you have to identify.
Part B - About the solar system and stuff - answer 3 questions from 4.
  • Q9 gets you to normalise rock samples based on mineral components and plot a graph.
  • Q10 is more an essay question about how planets form, where you have to write some of the steps in their formation.
  • Q11 is about some craters on Mars, and how they form. Again you have to describe mechanisms.
  • Q12 is about meteorites and their inclusions.
Part C - Astrobiology and the search for life - again 3 from 4.
  • Q13 is about evolution, the requirements for life and Panspermia.
  • Q14 looks at Europa and gets you to label images and say what is going on in resurfacing terms.
  • Q15 is about habitable zones around stars, and is maths based, which you then have to comment on.
  • Q16 is exoplanet detection using doppler and astrometry. Then follows this up by exploring what else you might find out.
I've had worse exams, I've also had better ones. I think I passed, but possibly not as well as I might have hoped. Oh well, nothing I can do now.

Wednesday, 21 October 2009

S283: TMA-4

The last TMA. I need a big score to up my OCAS average on this one. Alas not to be, despite spending far too long on it, repeatedly reworking it. I'm just not putting what is in the marking template apparently.

Question 1 is about evidence for water flow on Mars. You have to download a paper discussing recent evidence for water flow on Mars and compare the paper with details in the book.

Question 2 concerns rainfall on Titan, and the atmospheric structure there.

Question 3 concerns the Drake equation, and asks you to calculate civilisations based on some given numbers.

Question 4 is about extra solar planet detection using the Doppler method. It also includes details about transit detection, what its probably density is in comparison to Jupiter, and so what sort of planet it is. Also how it might have got there through migration.

Question 5 is all about suitability for life based on IR and light spectrum. Discussing possible spectra and what they might tell you, and what you would hope to see in some cases. Also reasons the planet might be habitable but still nto show up on the spectrum results.

Last TMA, not the mark I was hoping for, and in general the marks for this course have been hard to get compared to all the other courses I have done with the OU. I still got reasonable scores, but found it very difficult to get a good score on a TMA, as it seems very picky about minutia of detail. If you answer is right, but not what is wanted, you score less than otherwise.

Anyway - now just the exam.

Next S283 Prev S283

Friday, 18 September 2009

S283: TMA-3

Well, my worst TMA of the series (so far). One stupid mistake which probably accounts for a couple of lost points, and several questions where I miss the point.

Question 1: This is about 17O and 18O ratios, and what they say about stars. You have to calculate a few quantities and the rest is interpreting the results.

Question 2: Is about geochemical data for asteroids, and looks at rare earth element ratios. You have to calculate some data in a spread sheet for 3 different sample, and then plot it on a graph. You also have to do the same thing with δ17O and δ18O ratios. Then armed with this data make a case for the origins of the various samples.

Question 3: This looks at possible biological molecules, asks you to identify the general type of molecule, its use as a biomarker. Then you have to draw the chiral equivalents of them in a chemistry program.

Question 4: This asks you to discuss the habitable zone around a star, and also looks at habitable zones around larger planets and similar.

Question 5: This is about the martian meteorite ALH 84001 and the possibility that it shows evidence of microbial life on Mars. You have to discuss the evidence for and against. Finally it asks you to critically evaluate the evidence for the emergence of life on earth, but says you should do it in 50-100 words - which to be indicates a short answer. The sample answer contains a number of points that I missed.

Anyway, there it goes, hope to do better in the next one.

Sunday, 6 September 2009

S171: Empire of the Microbe

So another short course, to fill in a 10 point degree shaped hole.
This is a new course, first presentation. A scary prospect if there is an exam involved, but this is just the normal ECA so I feel confident.
What you get is
  • Empire of the Microbes course book
  • A DVD with a digital microscope flashg application and some videos
  • A study guide
  • An assessment handbook
  • A how to get help guide
All the rest is provided online, which due to a late sign up and some gremlins I've only been able to glimpse a couple of times before it declares me persona non-gratia. Anyway, the book looks up to the usual excellent OU standard, but with a TMA, an exam, and the S170 course to do, its getting scant attention so far.

Thursday, 20 August 2009

S283: Book2 - An introduction to astrobiology

Book 2 starts to get to some biology, and leave behind some of the geophysics, so its more in my comfort zone.
  • Chapter 1 starts by looking at the origin of life on earth. What it needs in terms of components, how it might have started and the clues left behind both fossil and molecular.
  • Chapter 2 looks at environments for life, and considers the habitable zone around the sun.
  • Chapter 3 is all about Mars, and the various attempts to find life there, including the notorious Martian meteorite.
  • Chapter 4 looks at the possibility of life on icy moons such as Europa and other places.
  • Chapter 5 is devoted to the moon Titan.
  • Chapter 6 is about exoplanets, those planets orbiting other stars and mostly about how they are detected.
  • Chapter 7 looks at exoplanets as possible habitats for life, and some of their properties that may aid or otherwise life development.
  • Chapter 8 looks at the potential to detect life on exoplanets from Earth, and the technology required for that to take place.
  • Chapter 9 considers SETI and CETI, interaction with extraterrestrial civilisations and how we haven't had any, and why that might be.

Whilst I found the first few chapters interesting, and the exoplanet chapters happened to coincide with a IYA lecture locally that was excellent, I found the book rather seemed to fizzle out at the end., or maybe it was me that fizzled out.

Sunday, 16 August 2009

S170: Darwin and Evolution

Its been a while since I did a short course, but I have 20 points of hole in my degree and this is one way to fill it.
So I signed up, and its arrived. What you get is
  • An S170 Study guide - a booklet that tells you where stuff is and how to get to it. Increasing the material is online now.
  • Help with short courses leaflet
  • The 99% Ape book - looks good - not too bad at 244 pages. Lots of colour pictures and diagrams, so looks good.
  • S170 DVD, Darwin and evolution. It includes episodes from the series Jimmy Dohery in Darwin's Garden on it.
  • Assessment handbook
As with most short courses, there is only one written assignment, but it's not yet available as the course hasn't officially opened. Anyway, onwards with it (once I've finished my other course that is - oh maybe just a peek then...)

Friday, 26 June 2009

S283: TMA-2

TMA 2 comes around, and there is more work to do on book 1 in this one. It has just the 4 questions.

Question 1 is about atmospheres. You have to start by discussing techniques for analysing atmospheres. This is followed up by some calculations on partial pressures and what sort of conditions could make for frozen carbon dioxide on the Earth and Mars.

Question 2 is about Keplers laws. It starts by getting you to state them, and then apply them to an asteroid. Based on this and some other data you then have to work out what sort of asteroid it is, and whether it is a potential threat to the Earth.

Question 3 is an essay! Its 600 words comparing and contrasting the atmospheres, structures and properties of Jupiter and Neptune. Well 600 words is either a lot, or not much depending on how much you have to cover. In the end, with some diagrams and tables and a couple of photos this turns into not too bad an account, but its when do you declare it finished!

Question 4 you are asked to discuss various theories of solar system formation. Based on the latest exoplanetary observations, it seems fairly clear that the current models are inadequate, but anyway to get the marks you have to describe what the books tell you.

Not too bad a TMA, and a lot better mark than the last one.

Saturday, 20 June 2009

S205: The Exam

So the exam day dawns. I generally try to work through as many past papers as I can before an exam. Usually going through them 2 or 3 times.
The first time through is very slow, as I usually can't do or get stuck on nearly every question, or have nagging doubts about the answer. Either way, it means rereading sections of the books.
By the second time through, I've usually got better and can answer some of the questions without help, and others I still have to look up and check.
By the third time through, I'm no longer doing all the questions and only focusing on the areas I want to do. By this time, I'm starting to remember the answers anyway, so there isn't a lot of point going through them again.

So this plan worked well, although I quickly realised I just wasn't going to do much on book 9 - there is just too much seemingly random stuff in there to learn. I found the kinetics and molecular modelling and NMR/IR all quite good - but they are often in the same section so end up mutually exclusive.

There are 4 sections to the exam:
  • A is short answer questions - you answer 8 out of 12
  • B, C, D are long answer questions, and you do 1 from each section out of 3.
A questions are from all over, some can be answered in a couple of words, or with a simple diagram, others require maths of explanations. So its good to pick out the really short short answer ones, and build up some time for use later.
B is usually organic reactions and synthesis. Usually a retrosynthesis with analysis and some of the forward steps required. The rest are more conventional diagrams, but lots of curly arrows required (I took in a green pen just to draw curly arrows with).
C is typically kinetics, molecular modelling and NMR/IR stuff
D is often VSEPR, symmetry, and maybe some spectroscopy, thermodynamics (mainly Born Harber cycles) - and something on book 9.

Once the exam was a couple of days away, I sat down and did a timed exam using the sample exam paper they provide. This is good for showing up weaknesses, but very good for working out how much time you will have for different sections.

Anyway, in this exam I found a reasonable 8 I could do - I know your suppose to read the paper and digest, but I rushed straight into question 1, its nearly always of the same form. Fill in an orbitals diagram from an element. A nice easy 5 marks, as long as you get it right! In my mock I filled in 16 electrons when it asked for 14.

Question 2 was also so easy - I happened to know the answer, that I just wrote it down. You had to identify a compound from 4 possible options, and it happened to be very similar to a past paper - so although it was a book 9 question - I just knew it (or hope that is the case!).

Then I had to pause, and flicked through the whole paper.
I sorted out the ones I could do in the A section, and picked a couple of likely looking long questions. I worked through the A questions, leaving the thermodynamic one to the last, as that although fairly easy (and you can often check you got the right answer in the data book) it takes a little time and is easy to miss out a 1/2 or similar bit.

As usual, there is one that you can answer most parts of and one bit you can't, should you do this question or pick another one?

In the end I did about 10/12 from A, just in case (as they take your best marks). Also 5 long answer questions. I hope it's enough.

Monday, 15 June 2009

S205: TMA-6

Last and final TMA, and one that gave me considerable heartache! Its mostly on book 10 which is full speed organics.

Question 1 is about the production of biodiesel. On the face of it, this looks a nice simple question. However the mechanism is basically a transesterification, related to saponification (soap making). Now both those words sound long and complex, but actually the reaction is really very straightforward. There are two parts to the question, the first is to predict the products of the reaction.
The second is to draw the mechanism.
Well firstly, I usually need to draw the mechanism to be sure I know what the products are, but thats OK I can do the second bit first. The real issue though is there are 6 marks for the first part, and 19 for drawing the mechanism. Even if I do it in painful detail, I can really make more than 2-3 maybe 4 steps out of the whole thing. For 19 marks, this sounds warning bells that I've misunderstood the question. I returned to the question time and again looking for the missing part, even donwloading a research paper on the topic - but no it appears it really is that simple!

Question 2 is some basic organic reactions to extend alkane chains. One part you need to pick appropriate reagents, the other part two different directions for the same reagent. Fairly striaghtforward, but after drawing the mechanisms of the two reactions, I've got a lot more diagram than Q1, and this is only worth 15 marks for the whole question.

Question 3 is on radical reactions - rather scary reactions that have been tamed in recent years. Gives me a chance to draw fishhook arrows, but its basically derived stuff from the appropriate chapters.

Question 4 is on retrosynthesis. You have to undo the reaction to find the products and a way of bringing it about. It leads you through the steps as part of the questions quite nicely, provided you get the right bits. There are some comments on steroechemistry, and on reagents you might need to bring about the final results. Just a case of working through it really.

So - that is all the coursework done! Just the exam to look forward to :-/
(However - I ended up getting the best mark for this TMA out of the whole course, so Q1 must have been "just that easy").

Thursday, 28 May 2009

S205: TMA-5

Last but one TMA. Not one I'm looking forward too as much. Its got essay like things in, and its so easy to lose marks in these. Oh well, after all the biology essays I've done, and skating quickly over the archaeology ones, I ought to be used to this sort of thing, so hey ho.

Question 1
In this one, you have to prepare an overhead transparency for a 1 minute talk. Of course almost no one uses overheads these days, they use powerpoint or similar. Gone are the days (hopefully) of getting acetates shrink wrapped around the photocopier drums. You have to prepare the overhead, on the subject of "The use of VSEPR to predict the structure of tellurium tetrachloride". You then have to write a script that when read aloud will take 1 minute to read in a normal voice and taking breaths etc. Apparently in some previous versions of the course, you actually had to record the talk and post a tape with it on, but thankfully that isn't required now. Your tutor has to read it and decide if you are within the time limits. You can annotate the script a little with markers to show where you are pointing to on the slide.
Anyway, not too bad a question - the topic is fairly striaghtforward, and a few graphics help spice up the slide.

Question 2
This is about book 9 - p-block materials. You have to identify an element given a few facts about its appearance and its reactions with flourine. Then a bit about its oxidation states, and then its reactions with acid and alkalis.

Question 3
Some entropy sneaks back in, as you have to compose a formation reaction for BCL3. Then draw a lewis structure for it.
Thats followed up by a full blown thermodynamic cycle for the construction of it so you can work out the molar enthalpy. Finally an equation for the formation of BCL3 from boric oxide and phosphorous pentachloride.

Question 4
More identification of solids and solutions based on some reactions. Some reactions are described and you have to predict what will be formed, then these in turn react and so on. Of course if you get step 1 wrong, your a bit lost for the rest of the question.

Question 5
Its essay time. "The chemistry of bromine can be predicted from its position in the Periodic Table". A report of 600 words explaining this. You can include graphs, diagrams, pictures, tables etc, and I throw in quite a few of these as it helps give me something to do rather than just writing words, and it also breaks up the structure a bit. Even a picture of dear old Dmitri Mendeleev helps give it a bit of colour.
You have to do all the usual stuff, introduction, conclusion, references etc. Anyway, after a lot of tinkering with it, I get something I'm not altogether happy with, but can't see how to improve it in the time and space available.

So - just one more to go, then the exam looms on the horizon.

Tuesday, 19 May 2009

S205: Book 10 - Mechanism and Synthesis

Book 10 - the last real book. There is a Book 11, but its more of a pamphlet and discusses how to write essays and make presentations and stuff like that.

Anyway, Book 10 is all back to organics and synthesis.

First there is a whole section on carbonyl compounds and reactions - those things with a C=O in them somewhere. I guess you either like this sort of stuff, or not. I'm rather less than impressed with it all, although the rules seems straight forward there seem to be a lot of them.

Then the next section is all about organometallic reactions. Grignard reagents. Despite not really knowing how these are made, they seem awfully useful for glueing bits of molecules together.
It starts with magnesium compounds, then we move through into sodium, lithium and copper compounds. Then it finishes up with organoboron.

Section 3 looks at radical reactions - where you get compounds with single electrons lieing around. These use to be so rapid and violent to be unusable, but recent times they have found ways of taming them to make a useful way of doing things.

Section 4 is about retrosynthesis mostly. So knowing what you want to make, how can you work backwards to find a way to make it from everyday molecules. Basically there is no right way or wrong way, but some rules help you to break up compounds to make it easier. It seems a combination of science, experience and a touch of art.

The last section looks at biosynthesis, which rather puts chemist in the shade. Making complex molecules at room temperature and pressure without breaking a sweat.

Finally, there is a case study on polymers.

Phew - all done - finally got to the end of what has been a long course squeezed into what seems too short a time!

Tuesday, 12 May 2009

S283: TMA-1

Well compared to the chemistry I'm doing alongside this, I find this TMA reasonably easy. Possibly too easy as I get a less than expected mark for it. That will teach me!
Lets see - what does it have in store?

Question 1 is about the formation of the solar system. When it formed, why rocky planets are in the inner and gas giants in the outer. Stuff about ring systems and density, and the asteroid belt. Not too bad for a start.

Question 2 is geology. What the structure of the earth is, what the layers are, how they are defined and stuff like that. Some bits on mineralogy and seismic data, and rounded off with xenoliths and what they can tell us about the structure.

Question 3 looks at various moons, and gets you to fill in a table. How old is the surface of each, what if any caused the resurfacing, and what was it made up of. Then you are given data about two imaginary satellites, and asked to work out from density and other information what sort of body they are likely to be.

Question 4 is about volcanism and cryovolcanism. What basalt is so common, what makes it so and so on. More geology...

Question 5 is interesting, as you are given a picture of part of the moon, and have to work out various dimensions of the craters pictured, and then determine if they are simple or complex craters. I found acrobat reader has a great tool for this sort of measuring. Then you have to make various observations and hypotheses about the craters such as age and relative order.

Monday, 11 May 2009

S205: TMA-4

Another TMA - and they are coming thick and fast at this point. Two TMA's due in the same month! This TMA is a bit of a monster, but turns out to get my best mark so far, so maybe something is sinking in - although I suspect its just how it goes.

Question 1 is about analysis. You are given some weights of elements found in a compound and asked to work out the empirical formula for it. Its really not too difficult, as its sort of like the S103 stuff, but a bit more complex. A nice surprise after some of the nightmare questions!

Question 2 is all about identifying struture. Youy are given IR and NMR spectroscopy data, and based on this and the molecular formula, you have top work out what the structure is. I find the NMR pretty good to do. The IR is a little vague, but you can answer it pretty much just from the NMR data, and use the IR for confirmation.

Question 3 is NMR from the other direction. Given a particular structure, you need to predict what NMR peaks and troughs it should give you. Its not too bad - once you get the idea of carbon equivalence.

Question 4 is looking at oxoacids, and working out their strengths. Its fairly straightforward if you can relate it to Paulings rules and coefficients.

Question 5 is to write an essay plan for the essay that has to be written for TMA-5. An essay - in chemistry, I never thought I'd see the day! Oh well...

As I said, not a bad TMA - which I think is more down to the absence of complex organic reactions than anything else.

Wednesday, 25 March 2009

S205: CMA-2

So - there is another computer marked assignment to do. There are 35 question to be done, and they vary a lot in format. Some you have to work out a number and type it in. Others require ticking boxes, and so on. These have their strengths and weaknesses. Firstly its a computer marking your efforts, although the questions are reviewed by the course team. This does mean you can sometimes get what you think is the right answer only to be caught out on a technicality, like typing 2.0 when it is expecting 2. Mostly though its pretty good at taking reasonable answers - but of course can't apply the same common sense a human can.

You generally get 3 attempts at an answer, unless its a true/false type one. A couple of them I got completely wrong. One was on the symmetry of SeOCl4 using VSEPR - which even after 3 attempts I still got wrong, and couldn't work out why. My tutor suggested some possibilities given I knew the answer (it tells you once you get it wrong). I also checked it out with a chemistry lecturer friend and she came to the same conclusion as I had. After taking it up with the course team they explained (after the deadline) why their answer was right, but eventually they zero'd out the question as it was rather ambiguous. Even given the answer I couldn't see how you could come up with a definitive structure based on just the course notes - there simply wasn't enough data to cover these weird edge cases. The trouble with issues like this is that I find it suddenly undermines my confidence. Its not a silly mistake, its something I've thought about and still got wrong. I suppose whatever doesn't fail makes me stronger, but in reality it tends to lead to a certain fear of similar questions.

The other question I got wrong I could eventually see I'd just made a silly mistake. Its a bit weird doing these things, you tend to get CMA blindness. For instance I'd take all the data given, do all the calculations and come up with an answer - I'd probably check it too - and then look at the screen and see if my answer was there. If it was, I'd tick it, if not then I clearly need to try again. However often you get one of these calculations where you end up doing a load of steps and then the final one is to multiply by 2 -- or is that divide by 2... after due consideration you decide its multiply by 2, see the answer is there, tick and go. Wrong answer. My immediate reaction is not to do any more work (because I'm lazy by nature) but to assume it was divide by 2, and the answer is there to, so tick that and resubmit immediately without rechecking things. Wrong again! This is where you're 3rd chance comes in, and where you should sit down and rework the problem again - rather than phoning a friend or asking the audience.

Anyway - that was the last of the two CMAs in this course.

Tuesday, 10 March 2009

S205: Book 9 - Elements of the p-block

Oh no -its another vast book - 242 pages about lots of stuff - its information overload, and I'm not really sure what you are suppose to take away from this book. There seems far too much to learn, so in the end I just end up reading the book and hoping some of the concepts sink in ... hummm.

It starts off of, by looking at oxidation states and how you can work them out from various rules. That's not too bad.
The next chapter starts to look at acids and bases, and in particular extends the definition to Brønsted acids - which are compounds that can donate a proton or hydrogen ion.
So having just got the idea of a new type of acid, we have another new type in the next chapter - the Lewis acid. This is a substance that can donate a pair of electrons. Okkkayyy - just about getting that.

Next chapter is all about the chemistry of hydrogen - what it can do and how it can form hydrides and things like that. I'm sure there is some general message here but it seems like just a large number of different reactions.
Next we look at halides, and all manner of ways that the halogens can form compounds. Again a confusing number of different reactions.
After that - a real walk on the wild side as we look at those most unreactive of elements, the noble gases and the various compounds they can form. Its a bit like being told there is no Santa Claus that compounds of the noble gases can form compounds. I mean - the one thing you generally learn in chemistry is that compounds struggle to form bonds to make noble gas like electron shells. Then along comes xenon, and starts disrupting these well rehearsed truths.

After a brief foray into some trends in second and third row elements (which is also covered - better for me - in a dvd accompanying the book), we launch into group 3. Boron, aluminium and so on. Boron is plain weird, it eschews the eightfold way and is happy to make compounds with only a shell of 6 electrons. Its all rather disconcerting.

Then its time to look at group 4. Carbon, silicon and their ilk. It seems we've been doing precious little other than looking at carbon for most of this course, but here it is again.
Follow this up with a look at group 5 nitrogen, and phosphorous, and all they can do. Then its on to oxgen, sulphur and its pals.
Finally another look at trends and the book is done, except for a case study look at acid rain.

So much information, so many reactions - my head is spinning. How can anyone possibly remember a 10th of this stuff.

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.

Tuesday, 27 January 2009

S205: TMA-2

The second bit of coursework looms - and its name is TMA-2.
Four questions to tackle, based on books 4 and 5.

Question 1 is all about thermodynamics. You have to calculate a number of entropy, enthalpy and other things about substances. You also have to draw a diagram of a Born-Haber lattice energy diagram and work out lattice energy for GeI4 a substance.

Question 2 concerns kinetics. You have to come up with an general reaction rate equation and then it starts to drip in information that eventually allows you to solve it bit by bit.
You also need to use the computer program provided (kinetics toolkit) to plot a graph of the reaction rate.

Question 3 is about SN1 and SN2 reactions. You are presented with some reactions and told what they might produce, and from this you have to deduce if it is an SN1 or 2 type reaction. You then have to draw the reaction diagrams with curly arrows showing where the electrons are moving around. Then it goes on to get you to consider the enantiomers produced and which might be dominant.

Question 4 is similar to question 3, but with different molecules, and we are looking at elimination reactions rather than substitutions.

I managed to get completely wrong on the last one and follow it to its logical conclusion but starting from a false premise.

Thursday, 8 January 2009

S205: Book 6 - Molecular modelling and bonding

This book is a book in itself, in that for once it isn't split into sections and parts, but does basically what it says on the cover.
It looks at the theory of electron clouds and how bonds form between atoms. It goes into all the detail about orbitals and hybridisation. It looks at what happens to bonds between atoms of the same type, and between different types. It also has a quick look at what is happening in semi-conductors, which is a little bit of a detour, although there is a relationship I suppose.

The part I don't really follow is the whole bit about symmetry. I can see some of the symmetries, others are a little harder to spot. I'm not too sure why they are important though, and to what extent the rather complicated rules for classifying the different symmetries are useful.

Finally there is a case study that looks at drug design and how knowledge of the bonding sites can allow enzymes and drugs to be designed.

Chemistry seems increasingly to be a collection of complex categorisation rules and quite a bit of maths. The maths I can cope with, but there seems a lot to remember otherwise. Oh well, judging by the book count, the course is over half way through now!