Evil spirits

Methylated spirits. They’re useful for quite a few things. Cleaning windows, compact camping cookware and even killing mealybugs. We also know that you shouldn’t drink it, because it’s rather toxic. But why is toxic?

Well, the simple answer is so that people don’t drink it! Methylated spirits are about 95% ethanol (which we would classify as very strong Vodka), with a bit of methanol added to make it undrinkable. Ethanol and methanol are very similar-looking alcohols, with only one more carbon atom in ethanol than methanol. However, while ethanol usually won’t do much worse than give you a nasty headache, dehydration and the constant need to rid yourself of your stomach contents, methanol can cause blindness or even death. The reason methanol is so toxic is because of it reacts inside the body.

Chemistry time! Methanol is what we call a primary alcohol, and primary alcohols can oxidise (put simply, gain oxygen) to form aldehydes, which can then oxidise further to form carboxylic acids, such as acetic acid (vinegar). When we consume methanol, it is absorbed into the liver where is reacts with an enzyme called alcohol dehydrogenase. The alcohol dehydrogenase oxidises the methanol to methanal (an aldehyde), more commonly known as formaldehyde. Yes, that’s correct: your body is forming the same stuff that they preserve cadavers in … lovely image. Amazingly, it’s not the formaldehyde that kills you though! The body can quite easily get rid of the formaldehyde, but if it has no use for it, it oxidises again to create formic acid (a type of carboxylic acid). Formic acid is actually the same compound that ants give off when under attack and has that lovely characteristic ‘squashed-ant’ smell.  If the formic acid builds up in the blood, this is what causes the deadly side-effects of methanol.

So, in all seriousness, don’t drink metho. Not only will it taste terrible, but it’ll also most likely kill you by creating ‘squashed ant’ acid in your bloodstream. Not a pretty picture.

On a lighter note, what kind of ethanol-containing beverages do you enjoy consuming? Personally I like a glass of sparkling rose. Leave a bubbly comment below 🙂

A slightly safer way to consume ethanol.  Image courtesy of Henrik Abelsson (http://commons.wikimedia.org/wiki/File:Absolut_vodka.jpg)

A slightly safer way to consume ethanol.
Image courtesy of Henrik Abelsson (http://commons.wikimedia.org/wiki/File:Absolut_vodka.jpg)

Reference: http://andevidencelibrary.com/topic.cfm?cat=4089&auth=1


What do you call a parrot wearing a raincoat?

Polyunsaturated! (sorry, it had to be done at some point!)

I went out for dinner last night and then had pancakes this morning, so I’m feeling like I need to eat a little more healthily over the next few days, which got me thinking about fats.

Fats are actually a type of ester. As every high-school chemistry knows esters are “sweet smelling compounds that give fruits their characteristic odours”. Esters are also the product of a reaction between an alcohol and a carboxylic acid. Fats are a special type of ester that are made from the reaction of an alcohol called glycerol with long-chain carboxylic acids.

There are three types of fats that we often see in the nutritional information on food labels:

  1. Saturated
  2. Unsaturated
  3. Trans

Saturated means that every carbon atom in chains is surrounded by 4 single bonds. This means that the chains are very straight and can very easily stack together, meaning that saturated fats are higher density and more likely to be solid than unsaturated fats. This can clog your arteries and so on, which is why saturated fats are bad for you!

Unsaturated fats have one or more double bonds along the chain. These can be either ‘cis’ or ‘trans’. ‘Cis’ double bonds mean that the chain will bend back on itself, creating kinks in the chain and making it harder for the chains to easily stack together, meaning they are more likely to be liquid. Mono- and poly-unsaturated refer to how many double bonds there are: mono meaning one and poly meaning many.

Trans fats are a different story. Instead of bending back on themselves and creating a big bend in the chain of the molecule, trans fats are a little bit sneaky. They arrange the double bond in such a way that the chain still remains almost perfectly straight, like saturated fats. Trans fats are basically very sneaky saturated fats in disguise.

Saturated, (cis) Unsaturated and Trans fat (Images from Wikimedia commons)

Saturated, (cis) Unsaturated and Trans fat
(Images from Wikimedia commons)

Is it just me, or does the cis-unsaturated fat look like a caterpillar? 😛

Anyway, now you know a little bit more about the fats that we commonly consume, you can make the informed decision to choose the caterpillar rather than the weird-looking centipede (saturated fats) and definitely shy away from the lazy caterpillar (trans fats). But what is your favourite unhealthy that you enjoy eating, even though it’s really bad for you? I’d definitely have to say strawberry pancakes, because that’s what I had for breakfast and they were AMAZING! Leave a gluttonous comment below 🙂

If it starts raining, then this parrot will be “poly-very-saturated”!
(Image courtesy of Frank Vassen, http://www.flickr.com/people/42244964@N03)

Honey, honey

Sorry about this being late – I completely forgot!

Anyway, back to business. Being late made me think of eating a slice of humble pie, and that would definitely be something sweet and what is sweet and delicious? Honey!

Honey is not only delicious, but it’s also good for you. Honey contains two main types of carbohydrates (which I will get to in a moment), and darker honeys, like Jarrah, have been to contain different minerals and trace elements, so it’s a sweeter way to get some nutrients than taking multivitamins.

There are two types of sugars in honey: glucose and fructose. These are two monomers that actually join together to form sucrose (ie.  “sugar”). They both form ring structures (see below), but have different numbers of atoms in them – glucose has 6 in the main ring (forming a hexagon) while fructose only has 5 (forming the pentagon).

Glucose (left) and Fructose (Images from Wikimedia Commons)

Glucose (left) and Fructose
(Images from Wikimedia Commons)

More atoms means more electrons, which helps increase attraction between molecules, meaning they are more likely to join together to create a solid. This means that glucose has a lower melting point that fructose and is therefore more likely to be solid at any given temperature. Therefore, if you have lots of glucose in your honey, it will crystallise very easily. If you have more fructose, it will be liquid. Essentially, the “runniness” of honey is dependent on the ratio of these two sugars.

So now you know how to make runny honey! What’s your favourite way to eat honey? I personally like it in my cup of tea, but what are your preferences? Leave a sweet comment below 🙂

Honeybee collecting nectar.  Image courtsey of Sajjad Fazel (http://en.wikipedia.org/wiki/File:Honey_Bee_takes_Nectar.JPG)

Honeybee collecting nectar.
Image courtsey of Sajjad Fazel (http://en.wikipedia.org/wiki/File:Honey_Bee_takes_Nectar.JPG)

Such a pain!

I was feeling a bit sick when I woke up this morning, so I thought it would be appropriate to have a rant about drugs – specifically, painkillers. Everyone has taken painkillers at some point in their lives, including aspirin, paracetamol, ibuprofen or even tramadol, codeine or morphine for stronger pain.  But looking at the structures of these drugs, there is one thing that is immediately obvious (well to me – others who study pharmacology may think differently): they all contain aromatic rings!

Ok, time for some theory. In organic chemistry, atoms form bonds to each other to create different molecules. These can be single (2 electrons), double (4 electrons) or triple (6 electrons) bonds, each with varying strength and different bonds will be formed depending on how many electrons are available and so on. There are also two main types of carbon chains – straight chain and cyclic (see below).

Image from Wikimedia Commons

Image from Wikimedia Commons

Image from Wikimedia Commons

The cyclic chain (top) joins together again on itself to form a ring, while the straight chain doesn’t – fair enough? These structures both contain only single bonds (2 electrons between each atom). Here is how it looks if we add a double bond to the cyclic chain.

Image from Wikimedia Commons

Image from Wikimedia Commons

The bond on the right now contains 4 electrons instead of 2 – all ok? We can add some more electrons to these bonds, and change the properties of this compound. BUT, if we have 3 double bonds inside this hexagon-shaped ring, we get something rather interesting.

Image from Wikimedia Commons

Image from Wikimedia Commons

The first cyclic compound (that looked like a hexagon, only single bonds) is called cyclohexane. When we add a double bond to that we get 1-cyclohexene, because the double bond is at position 1. So, we might guess that this compound with 3 double bonds could be called 1,3,5-cyclohexene. But no … this compound is called benzene. In benzene the “double” bonds that you can see drawn in the structure aren’t actually fixed in place. The electrons are ‘delocalised’, meaning they can move around the ring, so instead of 3 double bonds within a cyclohexane-type ring, there are actually the equivalent of 6 one-and-a-half bonds within the ring. Weird, huh!?

Due to the delocalised electrons within the ring, this makes benzene very, very stable and unlikely to react with other compounds. To get it to do anything, you often have to use very harsh conditions – strong acids and bases and very high temperatures – to get any kind of recent reaction going. For instance, strong acids (sulphuric acid and nitric acid) are required to make trinitrotoluene, better known as TNT. Benzene is also found in clothing dyes, including the first synthetic dye mauveine. Oh, and it’s also really useful in making pharmaceuticals!

I’m feeling a little better now, though that was probably more due to the expensive yoghurt I just bought rather than panadol! Question time: what’s your preferred way to get rid of a headache? Mediation? Having a sleep? Taking two aspirin and hoping for the best? Leave a shcheming comment below 🙂

Image courtsey of Wikimedia Commons

Image courtsey of Wikimedia Commons

Mon anniversaire

Birthdays are something that we all love. We all celebrate them in our own unique ways, and I can’t remember ever having a bad day on my birthday. I’ll turn twenty the day after this is published (ARGH!), so I thought it would be appropriate to have a ramble about some chemistry related to birthdays – more specifically, helium balloons.

Who doesn’t love playing with helium balloons? I’ve never tried it myself, but I’ve known a few friends to inhale the helium and then we’d all laugh at their high pitched voices. And while helium is quite fun to play with, it’s also quite special. Helium is what is known as an inert or noble gas. In other words, it’s quite happy the way it is and (most of the time*) can’t be bothered reacting with other elements.

But what’s so great about noble gases? Excellent question! Noble gases are like the very rich and very exclusive group you find at every high school – only certain people are allowed in, but you can use them from time to for your own exploitation. Since noble gases generally don’t react with other elements, this means they’re really great when working with  or synthesising compounds that are sensitive to nitrogen. Usually nitrogen is the gas of choice to protect air-sensitive reagents from the outside world, but if that fails, then argon is an excellent substitute.

Noble gases also very, very low boiling points, meaning that in their liquid form, we can use them to keep things cool. Helium boils (forms a gas) at about 4 degrees Kelvin (-269 degrees C), which is rather chilly! We use liquid helium to cool the superconducting magnets used in MRI scanners, which are the gold-standard of medical imaging technology and used to diagnose a whole host of conditions. Liquid neon, which is a little bit warmer (around -246 degrees C) is also used in cryogenics as it has a much better refrigerant capacity than liquid helium – 40 times better, actually! – and 3 times better than liquid hydrogen.

Oh, and since helium is very light and doesn’t have the tendency to explode when exposed to oxygen, it’s replaced hydrogen as the gas in blimps since the Hindenburg disaster in 1937. Helium is also great for blowing up balloons for parties, although the fun can be short-lived if you let go of the string while standing outside. (Yes … I speak from experience.)

All this talk of helium and gases is making me feel rather lightheaded, though I’m sure than can be fixed with a good dose of cake … and then a bit more … and then a bit more than necessary. (If you haven’t already, check out my cake rant.) But enough about my inability to stop eating cake! What’s your favourite use of helium? Leave a whimsical comment below 🙂

*Under the right conditions, I think you can force helium to react with fluorine (ie. the most anxious and needy element in the periodic table), but for the most part, these gases are chemically inert.

Image courtesy George Chernilevsky

Image courtesy George Chernilevsky

Mirror mirror on the wall …

… which of you smells sweetest of all?

I recently wrote a review about how science and scientists are portrayed in the TV series Bones, which you can find here. In Aliens in a Spaceship, Dr Brennan and Hodgins use perfume to perform a particular chemical reaction to help them analyse a soil sample so they can find out where they’re buried. This got me thinking about scents and molecules that we can smell, which took me back to first year stereochemistry and chirality.

Time for a quick chemistry lesson! Isomers are molecules with the same atoms arranged differently – for instance C4H8 could look like this:

Or more like this:

Both molecules have 4 carbon atoms and 8 hydrogen atoms  they’re just joined together slightly differently. You can get different types of isomers, including enantiomers of chiral molecules. Chiral comes from the Greek word Keir, meaning hand. Molecules are chiral if their mirror images cannot be superimposed on one another (remember, chemistry is 3D, so atoms can be facing backwards and forwards, as well as up, down, left and right!). Enantiomers are the mirror image isomers of a chiral molecule, and the two enantiomers can have very different chemical properties.

Oranges and lemons are both two different fruits that we can distinguish because of their colour and their smell. But the molecules responsible for their unique perfumes are actually enantiomers!

The only difference between the two enantiomers is the direction the bottom section is facing. The broken line in the left molecule (which smells like oranges) represents it facing away and the wedged line in the right molecule (which smells like lemons) represents it facing towards us. The story is the same for spearmint and caraway! They are both enatiomers of a molecule called carvone, and depending on the direction of a single bond, we detect them as different scents.

But why? Basically the smell receptors in our nose detect different scents through a “lock and key” type of mechanism. You need the right combination to fit together. Due to the 3D arrangements of the enantiomers, the smell receptors in our nostrils are sensitive enough to detect them as completely different things! I’m not sure if this is very intelligent or very stupid, but it makes the world a little more interesting I guess.

Molecules use mirror images to play havoc with our senses, but what do you like best about mirrors? I know I enjoy pulling stupid faces in front of mine. Leave a reflective comment below 🙂

Image courtesy of Paul Reynolds (http://www.flickr.com/photos/bigtallguy/)

Image courtesy of Paul Reynolds (http://www.flickr.com/photos/bigtallguy/)

Rice power!

On Friday night I did something very intelligent. It was raining and I was trying to rush from the car to the front door, carrying a lot in my hands while holding an umbrella, and in this process I dropped my mobile phone in the front garden. My mum was the one to find the casualty about 8 o’clock the next morning, and we both believed it to be a lost cause. After previous suggestion from a friend, I buried my sorry-state-of-a-phone in dry rice and waited anxiously.

But why would you want to bury a soaking phone in rice? This is because rice possesses the capacity to be very hydrophilic. Time for some more chemistry! As mentioned in my first post, water is rather an amazing substance. So much that scientists have created a classification for substances accordingly to their ability to mix with and absorb water. Hydrophobic substances repel water – they’re almost “scared” of it. Hydrophilic substances, on the other hand, like to mix with water and are very good at absorbing it. By burying your wet phone in rice, it will absorb all the excess water and leave it good as new. Also, have you ever heard of adding some rice to your salt shaker? This is because the rice prevents the salt clumping due to moisture in the air. Rice isn’t the only hydrophilic substance humans have taken advantage of. Magnesium sulfate and calcium sulfate are commonly used in chemistry labs to remove any excess water from reaction mixtures and sodium chloride (table salt) is used to draw out the bitter juices in eggplant.

My phone is still in rice ICU, but it managed to turn on with a little coaxing last night, so fingers crossed! Rice isn’t just good for rescuing wet electronics – it tastes pretty good too. What’s your favourite rice dish? Mine would definitely have to be fried rice: warm, comforting and tasty. Leave a shcheming comment below 🙂

Image courtesy of epSos (http://www.flickr.com/photos/epsos/)

Image courtesy of epSos (http://www.flickr.com/photos/epsos/)

Coffee Buzz

For many of us the day begins with breakfast and a cup of coffee. The rich, bitter aroma of roasting coffee beans is enough to make many of us salivate. It perks you up and gives you that extra kick to get through the morning. As many of us know, the chemical in coffee (as well as tea, chocolate and various energy drinks) that gives you this nice kick is 3,7-Dihydro-1,3,7-trimethyl-1H-purine-2,6-dione – more commonly known as caffeine.

Caffeine is psychoactive stimulant, meaning it gives us feelings of increased energy and alertness. It works by inhibiting adenosine, which supresses activity in the central nervous system, making us feel tired. Caffeine can do this because the two compounds have a very similar structure (see below).

Caffeine (left) and Adenosine molecular structures

Caffeine (left) and Adenosine molecular structures

Even though they’re quite different otherwise, those two rings in the middle are enough to allow caffeine to fit into the receptors that adenosine usually binds to, stopping adenosine being able to act as it usually would. Without the adenosine kicking in and making you sleepy, you instead feel perky and energetic and ready to take on anything!

Of course, drinking lots of coffee is no substitute for sleep, but it definitely helps to wake you up in the morning or, in the case of many students who leave their assignments to the last minute, help you stay up all night. When do you drink the most coffee? Leave a sleep-deprived comment below 🙂

Image courtesy of SweetOnVeg (http://www.flickr.com/photos/sweetonveg/)

Image courtesy of SweetOnVeg (http://www.flickr.com/photos/sweetonveg/)

A Sticky Situation

One of my favourite books that I read as a child is Matilda, by Roald Dahl. The story of a young girl who just doesn’t quite fit in (and has epic superpowers!)  really appealed to me and excited my imagination, as it did for so many others. One of the chapters is called ‘The hat and the superglue’, where young Matilda sneakily applies a thin layer of superglue to the inside of her father’s pork-pie hat, which then sticks to his head and creates all sort of amusement. But why was that glue so strong that it made it impossible for Matilda’s father to get that hat off his head?

The reason, as always, is based in science! Superglues are made from a series of compounds known as cyanoacrylates. When they are exposed to water, they react with the water to form polymers. These polymers are very strongly held together, and if the cyanoacrylates form these polymers while wedged between two surfaces, they will then very strongly stick them together. Not only are superglues great for mending items around the house, but they’re also used as bioglues in medicine and for fixing broken bones and tortoise shells in veterinary science. For more information about superglues in forensic science, check out my podcast.

Like quite a number of great scientific discoveries, superglue and its stickiness was discovered by accident. Dr Harry Coover was working in Kodak laboratories, trying to make a very clear plastic that could be used for gun sights. During his experiments, he synthesised superglue, but upon finding it wasn’t useful for what he wanted, simply put the formula aside. Six years later he had another go with it, this time to trying to make a new plastic that could be used to make aeroplane canopies. It wasn’t exactly great for that either, but Coover did notice that it was an excellent glue, sticking objects together very strongly and also very quickly. Seeing the economic opportunities, Kodak made the first superglue (Eastman #910) a few years later, and the world has been a slightly stickier place ever since.

I’m not sure how much Matilda knew about the chemistry of the glue that she applied to her father’s favourite hat, though with all the reading she managed to fit i in, I wouldn’t be surprised if she had some idea about it. So come and shcheme with me – if you were in Matilda’s situation and needed the perfect prank to play on your parents, what would you have used? A hat and some very sticky glue, a bucket of jelly landing on their heads or just a face full of oobleck? Leave your answer in the comments below 🙂

Photo courtesy of John Ong (http://www.flickr.com/photos/ongline/)

Photo courtesy of John Ong (http://www.flickr.com/photos/ongline/)

Reference: http://www.straightdope.com/columns/read/2187/was-super-glue-invented-to-seal-battle-wounds-in-vietnam

Can anyone find a solution to this problem?

Sorry, but chemistry is full of bad puns, and this definitely won’t be the last! Solutions are pretty amazing, actually. They can be formed from many combinations of solids, liquids and gases and are found all around us. Tap water, metal alloys, wine, stomach acids, minerals, soft drinks, vinegar … the list goes on.

Before you think I’ve gone completely mad, allow me to explain. I actually wrote and performed a science show based around solutions chemistry for one of my units last semester, and the excitement over solutions hasn’t quite worn off.

Now, back to the madness. Solutions are made of a solute dissolved in a solvent. For example with vinegar, water is the solvent and acetic acid is the solute. There are three main ways we classify solutions depending on the amount of solute relative to the solvent: unsaturated, saturated and supersaturated. Unsaturated solutions can still dissolve more of the solute while saturated solutions have reached their solute capacity – they can’t dissolve any more. We can change this by changing the temperature and for most solids, this increases with temperature. For instance, you can dissolve more sugar in hot coffee rather than iced coffee. Something very interesting happens when we cool down heated solutions, though. If you boiled some water and saturated it with sugar and then allowed it to cool, the sugar would stay trapped in solution, but it would be more than could normally dissolve at that temperature. The solution would be what it called ‘supersaturated’. But something even better happens when we add some more of the solute to a supersaturated solution of sodium acetate.

You can also get the same effect by pouring supersaturated sodium acetate onto a crystal.

What’s going on? I hear you ask. Excellent question! As mentioned, the sodium acetate solution is supersaturated, so by adding a single crystal, it triggers a reaction that causes all the dissolved solid to ‘precipitate’ or crash out of solution. So if you’re not part of the solution, then you’re probably the precipitate! Supersaturated sodium acetate is used to make instant hand warmers – when you activate them, you’re causing the precipitation reaction (which happens to release heat in this case) and warms your hands. However, I’m sorry to say that not all precipitation reactions of supersaturated solutions are this spectacular – sodium acetate is quite instantaneous, but other solids like sugar and table salt won’t work quite as quickly.

I have another confession to make. Supersaturated sodium acetate was supposed to be one of my demonstrations for the science show I wrote last semester, but after much trial and error, I couldn’t get it to reliably work. The last straw was definitely at my final dress rehearsal when I had it all prepared and carried it over to the show table, and then had my hopes shattered as I watched it precipitate after it must have touched some of the crystals clinging to the side of the container. After some thinking and much concentration I found another solution to my problem, but it wasn’t quite the same.

Anyway, I’ve had some great experiences with solutions and some not-so-great ones. Share your least favourite experience with solutions in the comments below, and maybe we can dissolve our problems together 🙂