STUDENT SUPPLEMENT JULY 2008 • VOLUME 45 • NUMBER 4
Smart medicines Chemists target genes in drug design
ISSN 0013-1350 Bologna in sight? GCSE assessment UK chemists SWOT up on Do current tests deliver the aims alternative HE structures of new specifi cations?
ISSUE JULY IN THIS ‘INVISIBLE’ CLUES ISSUE Fingerprints are unique. There is no surer way of establishing a person’s Fingerprints never lie Plant power identity at the scene of a crime Artifi cial photosynthesis than by their fi ngerprints. But – tomorrow’s energy? often this crucial evidence is removed before the forensic team reach the scene and the criminal A day in the goes free. Now researchers in the life of… department of chemistry at the Adesola Obunge University of Leicester, in Regulatory aff airs collaboration with forensic consultant scientists in the Northampton Police’s scientifi c support unit, have come up with a method that On-screen will reveal fi ngerprints on metal chemistry objects, even when they have or bullet for example – and sebaceous glands, located in hair Can the thief avoid being been wiped or washed away with remove any residue. This ensures follicles, contains fats, oils and caught on camera? soapy water. we are dealing with a corrosion waxes. Bond suggests, based on reaction and not a reaction of the what they know about corrosion Plus… H’ residue. We apply a potential science, that the Cl– present in the That’s chemistry According to Dr John Bond, across the metal of ca 2500 V, at residue from NaCl or KCl attacks Q&A reporting in the American Journal the same time dusting the metal the metal and causes it to dissolve. of Forensic Science, in May, the with a conducting powder, ie very ‘An aeration cell is formed’, he says, Go for gold! method works by exploiting the fi ne granular carbon. The powder ‘with water and the ions acting as Prize puzzles fact that the residue from a preferentially adheres to the the electrolyte and the metal fi ngerprint corrodes metal corroded parts of the metal, acting as both the anode and the surfaces, following precisely the which we found to have a cathode. Electron transfer through ridge pattern of the prints as it potential of about 10–12 V less the metal results in dissolution of Editor Kathryn Roberts does. The characteristics of the than other areas of the metal. In the metal in solution’. Assistant editor metal change, allowing forensics line with the laws of physics, the Since the publication of Bond’s James Berressem to enhance and reveal the print. In particles fi nd the state of article, two police forces have used Design and layout contrast, conventional minimum energy.’ the technique to help solve crimes. Dale Dawson fi ngerprinting methods rely on a Fingerprint residues are typically Meanwhile, a chemistry graduate Infochem is a supplement to Education physical or chemical interaction made up from sweat from two is expected to take up a PhD in Chemistry and is published with the fi ngerprint residue, so diff erent glands. Sweat from the studentship in the department of bi-monthly by the Royal Society of Chemistry, Burlington House, once the residue has gone the eccrine glands, which exist in the chemistry at the University of Piccadilly, London W1J 0BA, UK. technique would be of no use. pores on fi ngers, comprises 98 per Leicester in the next academic year 020-7437 8656, e-mail: [email protected] Bond explained to InfoChem, cent water plus inorganic salts to unravel the fundamental www.rsc.org/Education/EiC/index.asp © The Royal Society of Chemistry, 2008 ‘We take a metal that is thought such as sodium and potassium chemistry and improve the Published in January and alternate
JUPITERIMAGES to have a fi ngerprint on it – a gun chlorides. In contrast, sweat from technique. months. ISSN: 1752-0533
Download a pdf of this issue at: www.rsc.org/EiC 1
InfoChem_July 08.indd 1 12/06/2008 14:31:40 E, ISSUE JULY
Natural photosynthesis produces billions of tonnes of energy in the form of sugar every year. In so doing carbon dioxide is removed from the atmosphere. Not surprisingly, scientists around the world are trying to emulate this process in the laboratory. But the promise of ‘artifi cial photosynthesis’ poses many challenges…
lants and trees do it. Algae do atmosphere from an oxygen-poor to an nCO2 + nH2 → n(H–COOH) → it. Even primitive bacteria do it. oxygen-rich one. In a two-stage process, carbohydrates + organic molecules (ii) They capture energy from the water is fi rst split into hydrogen and oxygen Today many scientists around the world Sun and use it to convert (reaction (i), sometimes referred to as the believe that if this process could be water and carbon dioxide into ‘light’ reaction because light is needed) and reproduced in the laboratory and developed oxygen and carbohydrates, such as glucose. the hydrogen then reduces carbon dioxide to on an industrial scale, we would have the carbohydrates and other organic molecules 6CO2 + 12H2O + Energy → perfect solution to our energy problem. By (reaction (ii), the ‘dark’ reaction because no PC6H12O6 + 6O2 + 6H2O 2050 scientists estimate that there will be an light is needed). This is photosynthesis, and began on Earth energy shortfall of 14 TW (1 TW = 1012 W). With
over two billion years ago, changing our H2O → O2 + H2 (i) over 100 000 TW falling on the Earth as sunlight, the potential of ‘artifi cial photosynthesis’ is huge. Not only does it off er Chloroplasts – the energy providers a route to sustainable hydrogen production and other useful fuels such as methane and
ethanol, but it also removes CO2 from the atmosphere, a key process with the potential to build other useful chemicals.
A By the 1970s, interest in artifi cial photosynthesis began in earnest. Scientists knew from earlier work on ‘photogalvanic cells’ (basically a dye in water plus a couple of electrodes) that they could generate electricity via charge separation and electron transfer reactions, but they had severe limitations. The amount of electricity produced was very small and the cells had to be extremely thin otherwise the ions would react in solution. So sustaining the output from such cells was diffi cult and scientists looked towards Nature for a better solution. But it’s not that simple. Natural photo- synthesis is incredibly complex. The energy of sunlight is transferred in the form of electrons and positive charges throughout a pathway of RUSSELL KIGHTLEY/SCIENCE PHOTO LIBRARY
2 You may copy this issue for use within schools
InfoChem_July 08.indd 2 12/06/2008 14:32:07 E,
myriad steps before the fi nal products – same angle and same orientation in every carbohydrates – are formed. Crucially, these chloroplast. This was confi rmed by steps often require up to four electrons. This Professor Richard Cogdell and his team at presents an enormous challenge to chemists the University of Glasgow in the 1990s by because they need to be able to store using X-ray diff raction studies. C l r h i electrons and used them at just the right time. Harriman explains, ‘Within the chloroplast, All chemical reactions done in the laboratory there are a series of precisely placed Another breakthrough in our involve transferring just one electron at any chlorophyll molecules in a protein matrix understanding of natural photosynthesis was one time. To stand any chance of replicating which is ca 60 Å (1 Å = 10–10 m) thick. It is a the elucidation of the structure of the catalytic and exploiting photosynthesis, scientists need masterpiece of engineering. Shine light on reaction centres in chlorophyll in 2004 by to know exactly what is going on in the one side and an electron will move in a series Professor Jim Barber and his team at Imperial natural systems. of jumps until it reaches the other side of the College, London. There are two very complex By this time they knew that natural membrane. The result is a battery with a enzyme systems which carry out the light photosynthesis occurs in specifi c membranes positive charge on the top of the membrane reaction – called photosystem 1 (PSI) and – chloroplasts – in plant cells. These high and a negative charge on the bottom. The photosystem 2 (PSII). Barber identifi ed the surface area membranes contain proteins and catalyst is able to store these until it gets precise location and geometry of a few critical light-absorbing pigments such as chlorophyll either four electrons or four positive charges, ions – manganese, oxygen and calcium – and carotenoids. Chlorophyll captures the and then it will make oxygen on one side and within the core of PSII, and this has led to light and transfers it to the reaction centre, ie reduce carbon dioxide on the other side. The research teams around the world looking for the catalytic site where the water-splitting way the chlorophyll species are arranged more robust catalysts that will do the same reaction takes place. Chlorophyll is ensures that the positive and negative charges job outside of the natural environment. The regenerated frequently during this process. never come together otherwise they would problem with the natural systems, explains This, Tony Harriman, professor of physical annihilate each other and there would be no Harriman, is that they are very elaborate and chemistry at the University of Newcastle, potential to do work. When you try to design totally unstable once they are removed from explains to InfoChem, raises another big this system in the laboratory it is impossible to their protein environment. challenge for an artifi cial system based on arrange the chlorophyll species in precisely Most of the current research in this area is organic molecules. ‘Organic molecules, such the correct positions so that these electron focusing on ruthenium and iridium oxides as as dyes, when exposed to sunlight for an transfer reactions take place to split water’. potential catalysts for an artifi cial system extended period will degrade. How such molecules can be renewed or repaired in an artifi cial system presents a huge challenge for Powered by fossil fuels, courtesy of photosynthesis chemists’, he says.
U N’ Originally chemists thought that photo- synthesis was occurring through a random distribution of chlorophyll in the chloroplasts, which they reasoned should be possible to replicate in the lab. However, over the past 30 years scientists have uncovered a diff erent picture. They now know that Nature has learnt to position chlorophyll molecules in precise
DAVID NUNUK/SCIENCEpositions PHOTO LIBRARY; PHANTATOMIX/SCIENCE PHOTO LIBRARY in the chloroplasts – at exactly the You may copy this issue for use within schools 3
InfoChem_July 08.indd 3 12/06/2008 14:32:45 “… . ”
ISSUE JULY
based on dye molecules. So far, however, back and forth, picking up a proton and two scientists have only been able to achieve electrons and depositing them for use in the effi ciencies of ca 0.3 per cent with such production of carbohydrates. Eng n n l… laboratory-based systems. Chemists, notably in the US and Germany, are looking for a catalyst that will mimic the M natural co-enzyme in the lab. Etsuko Fujita natural process, artifi cial photosynthesis is Mimicking the dark reaction is also highly and her team at the Brookhaven National still considered as ‘blue-sky’ research. Its desirable. Again, in natural systems this Laboratory in New York, recently reported a further development and exploitation lie in
involves a very elaborate mechanism – the new catalyst for CO2 reduction based on the hands of policy makers and funding Calvin cycle, named after Melvin Calvin one of ruthenium, which holds much promise for agencies, and a supply of high quality the chemists at the University of California, fuel production. chemists and engineers in the future to Berkeley who discovered it. In this process a At the present time, despite having taken deliver the breakthroughs. + co-enzyme system, NADP /NADPH, moves huge steps in our understanding of the Kathryn Roberts
that’s chemistry! Simon Cotton, chemistry teacher at Uppingham School, looks at the molecules in our lives. In this issue: asparagus and its after eff ects
I like asparagus, but why does it S S O However, further research in 1987 showed S makes my urine smell funny? HO that methanethiol was present in similar You are not alone. Some 43 per cent of urine samples along with other diff erent CO2H NH2 people fi nd that after eating asparagus sulfur-containing compounds, including (1) Asparagusic acid (Asparagus offi cinalis) their urine smells of (2) Methionine dimethyl sulfi de and dimethyl disulfi de. So rotten vegetables. Asparagus contains O it’s possible that diff erent people produce sulfur compounds such as asparagusic H CSH diff erent ‘blends’. 3 S acid (1) and sulfur-containing amino acids (3) Methanethiol (4) S-Methylthioacrylate such as methionine (2). These chemicals Can we detect these blends? are broken down in the body into small, O Some researchers say that the ability to smelly, sulfur-containing molecules such S S produce smelly urine is an autosomal as methanethiol, CH3SH (3). This smelly (5) S-Methyl 3-(methylthio)thiopropionate (sex-independent) inherited trait. Other compound is mixed into our domestic scientists have reported that anyone who gas supply so that gas leaks can be detected can smell this bad odour in their urine can Asparagus tip – by methanethiol’s familiar bad odour. smell it in the urine of anyone else who sulfur compounds has eaten asparagus, with ca 10 per cent smell Are other compounds involved? able to detect the smell at very low In 1975 scientists analysed ‘asparagus- concentrations. This suggests a tainted’ urine samples, using gas genetically-determined hypersensitivity to chromatography coupled with mass these smelly sulfur compounds. ■ spectroscopy, and identifi ed two larger molecules, S-methyl thioacrylate (4) If you want to test your chemical knowledge with an ‘asparagus pee’-related problem, ask your teacher for your and S-methyl-3-(methylthio)thioprop- institution’s copy of the Royal Society of Chemistry book ionate (5), but not methanethiol. Kitchen chemistry and turn to page 109. JUPITERIMAGES; FRANCIS LEROY, BIOCOSMOS/SCIENCE PHOTO LIBRARY
4 You may copy this issue for use within schools
InfoChem_July 08.indd 4 12/06/2008 14:33:31 J n th H r s… AVOIDING DETECTION: can you fool an infrared security camera?
In The Thomas Crown aff air, Pierce Brosnan is sensitivity of the camera – producing a Thomas Crown, a rich playboy who spends ‘white-out’ on the screens – which allows him his time stealing priceless pieces of art. In one to go about his business unseen. So can you scene Crown steals a precious painting from fool a state-of-the-art thermal camera by an art gallery. The painting is in a room with using this trick? thermal imaging (infrared) security cameras. These cameras image heat rather than light Thermal cameras Thomas Crown tries to remain cool so they work well during the day or at night. Modern thermal cameras are sensitive to a thermal camera. I tried observing a person Before Crown steals the painting he leaves a wide range of infrared energy produced by through the camera in a small room as the suitcase in the room containing a heater, the temperature of the objects around them. heater was turned up to maximum and I was switched on. He does this to raise the They give a false colour image on a TV screen able to create just such a ‘white out’ on the temperature of the room and swamp the that depicts the variations in heat energy screen. But this was a deliberate attempt to coming from the objects in view. However, if try to produce this eff ect. In normal use the you heat up everything to exactly the same thermal cameras have such a wide response temperature it won’t necessarily make that this would never happen. Certainly not everything look the same on the screen. This over the sort of temperature rise you would is because diff erent objects emit and absorb expect with a small briefcase heater in the infrared radiation at diff erent rates even if centre of a large room. they are at the same temperature – it’s called Thermal cameras are usually set-up with their emissivity. So the thermal camera what’s called ‘automatic gain control’ (AGC) records the heat they emit rather than their which automatically adjusts the camera temperature. sensitivity (gain) for any changes in the If you take a tray of diff erent objects, put overall background. The AGC extends the them in an oven for enough time for them all useful range of the camera which will stop to reach the same temperature and look at ‘white-out’ occurring. them with a thermal camera they will appear distinct because they all have diff erent Caught (infra)red handed emissivities. So heating everything up to the So with a correctly set-up camera it would be same temperature won’t fool the cameras. extremely unlikely that such a simple stunt Modern thermal cameras are very sensitive could work. Since the security team had and will operate over a very wide range of several of these cameras around the room I intensities. So would it be possible to raise the think they would have been able to see temperature of the room by enough so that exactly what the thief was doing and so catch the thermal energy would be too great for the him before he left the building. ■ range of the camera and thus produce a white-out on the screen as seen in the fi lm? Dr Jonathan Hare, The Creative Science Centre, Chemistry It is possible to produce an eff ect like this No where to hide Department, University of Sussex, Brighton BN1 9ET by carefully adjusting the setting of the (www.creative-science.org.uk/TV.html). ADAM HARTDAVIS/SCIENCE PHOTO LIBRARY; MGM/THE KOBAL COLLECTION
You may copy this issue for use within schools 5
InfoChem_July 08.indd 5 12/06/2008 13:54:34 GO FOR GOLD! Test yourself with questions from the International Chemistry Olympiad
This question is adapted from Q3 of the 2005 UK Round 1 Chemistry Olympiad paper. ISSUE JULY he ‘simplest’ carboxylic acid is called methanoic acid and has formula HCOOH. It occurs naturally in ants Looking for answers to chemically T and used to be prepared by distilling them! When an related issues? Why not put them to ant bites, it injects a solution containing 50 per cent by volume of methanoic acid. A typical ant may inject around InfoChem’s professional chemists … 6.0 × 10–3 cm3 of this solution. Q: How accurately can we measure Avogadro’s (a) Given that the density of methanoic acid is 1.2 g cm–3, constant? (From Jason Hui of Bristol Grammar School.) how many moles of methanoic acid does the ‘typical Dr Michael Laing, University of KwaZulu-Natal says: ant’ inject? In 1986, the International Union Of Pure and Applied Physics (b) As soon as the methanoic acid is injected it 23 published the value: 6.022 136 7 (36) × 10 as being the best dissolves in water in the body to produce a solution value. This number was determined by accurate of methanoic acid. Assuming that it dissolves measurement of the diff raction of monochromatic x-rays immediately in 1.0 cm3 of water in the body calculate from a pure, single crystal of silicon. The accuracy of the the concentration of the methanoic acid solution technique rests on the accuracy of the x-ray wavelength, the density of the crystal, and the molar mass of silicon. These that is formed. (You may ignore the volume of the values were known to seven signifi cant fi gures. The earliest methanoic acid itself in this calculation.) measurements of Avogadro’s constant were by French The pH of a solution is related to the concentration of physicist Jean Perrin in 1909, who used the Brownian motion hydrogen ions as: pH = – log[H+], where [H+] stands for the of small particles in suspension. He found values between concentration of hydrogen ions in mol dm–3. 6.5 and 7.2 × 1023. (c) The pH of the methanoic acid solution produced Getting a good, accurate and dependable number is not above was 2.43. What is the concentration of easy. Chemistry books of 1950 quote many diff erent values: 6.0220, 6.0225, 6.020, 6.025 × 1023. hydrogen ions in this solution? You can rely on this new value to be accurate to about one Methanoic acid is a weak acid and so is only partly ionised part in 600 000. How does this compare in simple terms? This in solution: – is equivalent to 1 cm in 6 km. Can you detect this with the HCOOH(aq) HCOO (aq) + H+(aq) naked eye? Or with any simple instrument? For practical purposes the value 6.022 × 1023 is a good number for use in (d) Calculate the percentage of methanoic acid molecules normal calculations. (For fun you might like to look up which are ionised in this solution.
‘Determination of Avogadro’s constant’ on Google.) The acid dissociation constant, Ka, is a measure of how ionised a weak acid is. For methanoic acid it is defi ned by SEND YOUR QUESTIONS TO: the following expression where again square brackets The Editor, Education in Chemistry, the Royal Society of Chemistry, written round a formula mean the concentration of that –3 – + Burlington House, Piccadilly, London W1J 0BA or e-mail: [email protected]. substance in mol dm : Ka = [HCOO ][H ] / [HCOOH] All questions published will receive a £10 HMV token. (e) Calculate the acid dissociation constant for methanoic acid.
Organic Prize Quiz winner WEB RESOURCES The winner of the Organic Prize Quiz published in May’s issue To see the 2005 Olympiad paper (and answers!) go to: of InfoChem was Charlotte Lynch of Birkenhead, Merseyside. www.chemsoc.org/olympiad Answers to quiz, along with a downloadable pdf version of To fi nd out more about how to take part in the RSC Olympiad InfoChem, can be found at http://www.rsc.org/Education/ competitions for UK sixthform students go to: EiC/issues/2008July/Infochem.asp www.rsc.org/olympiad
6 You may copy this issue for use within schools
InfoChem_July 08.indd 6 12/06/2008 13:54:53 A …
REGULATORY AFFAIRS CONSULTANT: Adesola Obunge
Adesola has spent the past three years working for Parexel Consulting as a regulatory aff airs consultant. She talks to James Berressem about her typical day.
Parexel Consulting is a life sciences consultancy fi rm that provides Her day-to-day work scientifi c, regulatory and business advice to help healthcare is varied and depends companies bring their products (drugs or medical devices) to market on the clients’ needs. quickly. Clients include several pharmaceutical and biotechnology She always has several companies in the UK and worldwide. Based in offi ces in Uxbridge, projects on the go at Ad l Ong Adesola is one of ca 70 staff in the regulatory aff airs department. once and these can range from writing applications to start clinical trials, through R preparing product licence applications to manufacture and sell a new The healthcare industries are regulated by international government drug, to auditing manufacturers’ processes and procedures to check agencies, eg the European Medicines Agency (EMEA), and the Food that they adhere to current regulations. and Drugs Administration (FDA) in the US, which ensure that Much of her day is spent at her desk reviewing product data and medicines and medical devices work and are safe. These agencies set proposals provided by clients, writing technical reports for clients, and out laws relating to the testing, manufacture and marketing of new contacting and meeting with clients and the agencies. Although drugs and medical devices. Adesola works with healthcare companies based in the UK, Adesola’s projects tend to be international because to ensure that their processes and procedures meet the regulators’ clients usually want to test, manufacture and sell their products requirements. globally. So she contacts clients and the regulators by phone or e-mail and holds frequent telephone conferences, which can mean early and late starts to her day because of international time diff erences. For each project, eg seeking authorisation to manufacture a new PATHWAY TO SUCCESS drug, Adesola fi rst checks what the regulations are and compares these with the client’s proposals, checking that supporting data ● 2008– r , egltry ff rs submitted by the client is accurate and complete. Adesola’s chemistry c t , Pr C ng, Ux id training helps her to understand the data provided by clients, which include information on the drug’s mode of action and how it is ● 2005–08, egltry ff rs cit manufactured. And if a topic is unfamiliar, she consults colleagues c t , Pr C ng, Ux id with specialist knowledge, eg in pharmacology. She collates these data in the application, presenting in a logical manner complex ● 2004–05, egltry ff rs c r, information in straightforward language. Having submitted an Wamad Hethcr , Bld application, Adesola awaits the verdict and feedback from the regulators, who may want the client to supply additional data prior to ● 2001–04, quty c r sci st , approval. Most of her time is spent negotiating with the client and GlxStKn , Wr regulators on changes to the application, sourcing additional data, and then re-writing the application until it receives approval. ● 1996–2001, BS (H s) C st ry t er nry (2.), U v rty S C Anr ws The diversity of the job attracted Adesola to a role in regulatory aff airs and she enjoys the challenge of working on new projects with ● 1995–1996, c st ry, hs, ilo y A- diff erent people. She is pleased to be in a career that requires her to l vs, Ox id Cleg , Nig i use the chemical knowledge she developed at university. ■
You may copy this issue for use within schools 7
InfoChem_July 08.indd 7 12/06/2008 13:55:23 £50 OF HMV TOKENS TO BE WON! FIND THE ELEMENT No. 3 Students are invited to solve Benchtalk’s Find the element puzzle, contributed by Dr Simon Cotton of Uppingham School. Your task is to complete the grid by identifying the 10 elements using the clues below. ACROSS ISSUE JULY 1. ______fi bres are used as a strengthening material; found in charcoal and all organic compounds. 2. Metals found in all salts that give a yellow fl ame test. PRIZE WORDSEARCH No. 40 3. Inert gas that reminds you of Superman. Students are invited to fi nd the 29 words/expressions associated with 4. Poisonous green-yellow gas used as a disinfectant. synthetic diamonds hidden in this grid. Words read in any direction, but 5. Used to make ammonia by the Haber process; found in air. are always in a straight line. Some letters may be used more than once. When all the words are found, the unused letters, read in order, will spell 6. Second most common metal in the Earth; corrodes in moist air. a further 10-letter word. Please send your answers to the Editor at the 7. Used in antiseptic solutions; black solid that forms purple usual address to arrive no later than Monday 4 August. First correct vapour when heated. answer out of the editor’s hat will receive a £20 HMV token. 8. Silvery metal that reacts with steam but only slowly with cold water. DSRDCLEPORTOLLAAY 9. Least dense inert gas (whose name means ‘sun’ in Greek). NREERSTRUCTURECRH OOYPYSENOTSMEGTEO 1 10 MSAOSUBSTRATESIAT 2
ANLSTSURFACEIGVCB 3
IENIANOBRACMBAATA 4 DSOTLFILAMENTSTIL 5 CDIILMOTAHARDEIOL 6 INSOIREACTANTSONS TOUNSOHEATSINKNCO 7 EMFSENSORTRENIBHF 8
HAFDIAMONDFILMAAP 9 TIIRHARESEARCHRML NDDPTTSYLATACORBA If you have found the correct nine elements, in 10 down you will have YRSLOOTGNITTUCIES generated the name of an uncommon member of the platinum metal SASTNALPMIANITERM family. Its name begins with a girl’s name. Please send you answers to: the Editor, Education in Chemistry, the GCRYSTALGROWTHRYA Royal Society of Chemistry, Burlington House, Piccadilly, London W1J ACTIVATION DEPOSITION GEMSTONES RESEARCH 0BA, to arrive no later than Monday 4 August. First out of the editor’s hat BARRIER DIAMOND FILM HARD RETINA IMPLANTS to have correctly completed the grid will receive a £30 HMV token. ALLOTROPE DIAMOND HEAT SINK SENSOR ATOM SENSORS HOT BALLS OF STRUCTURE Ne e Ar He Xe Kr CARBON DIFFUSION LAYER PLASMA SUBSTRATE CATALYST FILAMENT INERT SURFACE Kr Xe Ne He e Ar CRYSTAL GROWTH GASES REACTION SYNTHETIC
CRYSTALLISE GAS PHASE CHAMBER DIAMOND Xe f Kr f Ar Ne f He CUTTING TOOL CHEMISTRY REACTANTS Futoshiki Ar He Xe f Kr Ne chemical elements May PRIZE WORDSEARCH No. 39 winner no. 1 winner The winner was ChemNet member Robert Alford from St Nicholas Catholic High The winner was Chloë Guppy from He Ne Kr Ar Xe School, Hartford, Cheshire. The fi ve-letter word was CURRY. Broadlands School, Keynsham, Bristol.
8 Download a pdf of this issue at: www.rsc.org/EiC
InfoChem_July 08.indd 8 12/06/2008 13:55:49