toxic spill in hungary

Last week saw one of the worst environmental disasters in Europe of the last few decades when a toxic slurry was released into the river Danube in Hungary after the collapse of a dam wall at an alumina plant. The red sludge contained a highly toxic mix of poisonous heavy metals and corrosive alkali.


Alumina is pure aluminium oxide, a compound which can then be electrolysed to produce aluminium, the most abundant metal in the earth crust and therefore one of the most widely used worldwide. However, the production of this pure white compound from aluminium ore or bauxite requires the removal of the impurities from the ore using strong alkali. As the dam wall broke, the impurities and the alkali were both released in a toxic red torrent, distinctively coloured by iron oxide removed from the ore, that resulted in the death of 5 people with many more suffering chemical burns, and the relocation of hundreds who lost their homes. The eventual clean up operation could take 18 months.

Hungarian alumina plant disaster

the disaster in 50 pictures

synthesis explorer

Welcome to a brave new school year. To celebrate I'll share with you something shiny and new I've stumbled across.

It's called Synthesis Explorer and I've put a link to it in the resources side bar of the blog. It's a 'dynamic web tool to study key organic chemistry reactions'.

You can basically choose from a wide variety of starting compounds and react them to reveal details of the reaction conditions and reagents, creating your own synthetic pathways on an 'interactive canvas'. It will help you to develop your understanding of organic reaction pathways and allow you to revise organic chemistry in 'an interactive and dynamic format'.

Well that's what the blurb says anyway. It is actually quite impressive. You can also view a wide range of physical, structural and spectral data for each compound.

explosion of the month 8

This month it's one of my own. This is similar to a previous post showing hydrogen burning in a pringles tub, only slightly scaled up into a large coffee tin. As the hydrogen burns from the hole in the lid, air is drawn in through the hole in the base of the tin until the mix is just right....

13D class photo

Two things struck me when I saw this photo. Firstly, Ben appears to have had too much shandy. Secondly, George looks like he could have done with a bit more. Thanks to Cheryl for sending the picture in.

All the best in the forthcoming exams. It has been a pleasure to share your company over the last two years.

CHEM2 papers

The CHEM2 paper is next Monday and although you have probably had plenty of practise already, you may feel the need for some further fine tuning with past paper questions. Knock yourself out with these.

They are old syllabus questions, which means that the CHM2 papers represent mostly the thermodynamics and inorganic chemistry stuff, and the CHM3 papers are all your organic chemistry work. There may be the odd thing that is now taught as part of CHEM1, like the content on oil or structural isomerism, but most of the following papers will help you prepare fully for next week.

CHM2 written paper June 2008
CHM2 mark scheme June 2008
CHM2 written paper June 2009
CHM2 mark scheme June 2009

CHM3 written paper June 2008
CHM3 mark scheme June 2008
CHM3 written paper June 2009
CHM3 mark scheme June 2009

Any problems with the links, or if you need any more papers, let me know via email.

explosion of the month 7

According to the blurb accompanying the original video on YouTube, this blast was much larger than the navy mine clearance team intended. The black dust that appeared a few seconds after the initial explosion was the remnants of a sunk Second World War vessel caught up in the explosion, it is claimed. With that size of blast it's a wonder we didn't see any more exploding whales like last month.

CHEM5 papers

If you scroll down this post a bit you'll find some papers and mark schemes for your revision, although hopefully you'll have had many of the answers fully explained in class by now. Just remember that there are some synoptic elements to CHEM5, meaning that the board can ask you anything from earlier modules which have a link to the new content studied in module 5.

As far as I can see, the most likely subject areas to crop up again are:

Thermodynamics
· Calorimetry (from CHEM2)
· Equilibria and Le Chatelier (CHEM2)

Redox Equilibria and cells
· Redox behaviour of halogens (CHEM2)

Periodicity
· Physical trends in period 3, melting point, 1st ionization energy etc. (CHEM1)
· Solubility trends of sulphates/hydroxides (CHEM1)
· Extraction of aluminium (CHEM2)

Transition Metals
· Electron configuration (CHEM1)
· Shapes of molecules (CHEM1)
· Extraction of metals, iron, aluminium, titanium (CHEM2)

At any point they could very easily throw in a pV=nRT calculation as well, so make sure you know the standard units.

CHEM5 2010 written paper

CHEM5 2010 mark scheme

Specimen written paper

Specimen mark scheme

Older CHM5 papers can be found further down. Just be careful to ignore any organic chemistry or other module 4 based questions on the old syllabus papers. However, if you are resitting the CHEM4 paper then there will be some useful stuff on here for you to try on equilibria and acid calculations, as well as the essential organic stuff.

If you need any more old CHM5 papers then send me a quick email and I'll let see what I can do.

CHM5 2008 written paper (old syllabus)

CHM5 2008 mark scheme (old syllabus)

CHM5 2009 written paper (old syllabus)

CHM5 2009 mark scheme (old syllabus)

Sorry, I don't have an electronic copy of the written paper, but,
CHM5 2010 mark scheme (old syllabus)

Make sure you come in if you need any help.