The Very Useful Chemistry Quiz

Answer: ethanol (alcohol)

Methylated spirits is basically ethanol (ethyl alcohol). The "methylated" part comes from the fact that a small percentage of methanol (methyl alcohol) is added to pure ethanol to stop it from being used to make alcoholic drinks (!). Methanol is very poisonous, unlike ethanol which, although toxic in large quantities, does not have the toxicity of methanol.

Answer: alpha-cyano acrylate

Superglue is a solution of a chemical called alpha-cyano acrylate. This chemical undergoes a process called polymerisation, and this is what forms superglue. When you squeeze some superglue from the tube, polymerisation of alpha-cyano acrylate is initiated by small amounts of water on the surface of the object (and on fingers also! ;)), and this leads to the rapid formation of the polymerised version of the chemical. Superglue is immensely strong - one drop can support 2000lb (900kg)! If you ever find yourself in a sticky situation with superglue, try using some acetone to dissolve it.

Answer: sodium hypochlorite

Household bleach is a 3-6% solution of sodium hypochlorite (NaOCl) in water. There is no actual "chlorine" (Cl2) in bleach at all, although it does contain a chlorine atom (Cl). Sodium hypochlorite is, however, prepared from chlorine (Cl2) and sodium hydroxide (NaOH), which is perhaps where the name "chlorine bleach" comes from.

It is a very useful chemical in that it not only kills germs, but is also an excellent stain remover. Under normal household use, sodium hypochlorite breaks down into sodium chloride (table salt), oxygen and water, and has been recently found by the Swedish Environmental Research Institute to pose no environmental problems provided it is used in the correct manner. (Thanks to howstuffworks.com - an incredibly interesting website. If you haven't checked it out, make sure you've got a spare hour or three when you do go have a look!)

Answer: acetone

Nail polish remover has acetone as a major component. Acetone is an excellent solvent - in my experience as a chemist, I've found it dissolves pretty much all organic (carbon-based) chemicals! Of course, there are exceptions, but when I want to clean my glassware, acetone is the solvent of choice! So when you use nail polish remover containing acetone, all it's doing is dissolving the nail polish so you can wipe it away. You can also buy "acetone-free" nail polish remover; this contains another solvent called ethyl acetate which works in just the same way.

Answer: solid carbon dioxide

"Dry ice" is solid carbon dioxide (CO2). Carbon dioxide freezes at -78.5 degrees Centigrade. When dry ice "melts" it undergoes a process called sublimation. This means that it is converted from a solid directly to a gas, bypassing the intermediate liquid stage. This is where the name "dry ice" comes from - when it melts, you never get any liquid (unlike water ice), hence it's "dry".

Answer: graphite

Graphite is what does the writing when you use a "lead" pencil. The core of a pencil is made up of graphite, clay and a little bit of water to help hold the mixture together. Graphite is an allotrope of the element carbon. Allotropes occur when atoms of an element are joined together in different ways.

These different joinings give different solid forms of the element. Another allotrope of carbon is diamond. Graphite was discovered by a 16th century Englishman, who found a grey deposit under a tree that had been blown over by a storm and thought he'd discovered lead (hence, "lead pencils").

It was not until 200 years later that this "lead" was actually found to be graphite (named after the Greek word meaning "to write").

Answer: poly (vinyl acetate)

OK, so the "PVA" in the question probably gave this one away! PVA = poly (vinyl acetate). PVA glue is an emulsion of the polymer poly (vinyl acetate) in water. The solution is fairly viscous and when it dries, it gives a nice clear finish. PVA can be used to make poly (vinyl alcohol), which is can be used to make the popular children's toy "Slime". All that needs to be done is mix a solution of poly (vinyl alcohol) with a solution of Borax with a little bit of dye and voila - Slime! Well, it's not quite that simple, but that's the general idea.

The borax makes cross-links between the polymer molecules, making much larger molecules that are even more viscous than the original polymer solution.

Answer: acetylsalicylic acid

A tablet of aspirin contains pure acetylsalicylic acid and a bit of binder to help hold the tablet together. Aspirin is a remarkable substance in that it can act as an analgesic (to relieve pain), an antipyretic (to lower fever) _and_ an anti-inflammatory agent (to reduce inflammation).

It was first synthesised in 1853 and was accepted into widespread pharmaceutical use at the end of the 19th century. The parent compound salicylic acid was also known as spiraeic acid, and the name "aspirin" was derived by taking the "a" from "acetyl" and combining it with "spir" taken from the acid's name. Aspirin can cause irritation of the stomach, and due to this, its popularity has declined recently (in favour of other medications such as paracetamol, ibuprofen and acetaminophen) but it is still the most widely used drug for the treatment of illness or injury.

Answer: ethylene glycol

Antifreeze is an ethylene glycol-water mixture. Water is an excellent conductor of heat, which is why it's used in car radiators, but it freezes at too high a temperature to be used on its own. It's mixed with ethylene glycol to lower the freezing point - a phenomenon known as freezing point depression (this is the same phenomenon that makes pouring salt onto snow effective in making it melt faster).

The ethylene glycol molecules act as "impurities" in the water, meaning that when the temperature gets low, the water can no longer easily form the regular 3-dimensional solid lattice it does when it freezes, so the temperature must be taken lower to freeze the mixture.

A 50:50 mixture of water and ethylene glycol freezes at -37C (-35F) - very comforting to know when you're driving in a snowstorm!

Answer: hydrogen peroxide

Although there are other substances that will lighten hair, hydrogen peroxide (chemical formula H202 - looks like water, but very different!) is still very common in hair dye preparations (especially ones designed to turn you into a blond). The hydrogen peroxide in the preparation acts as a bleach and strips the hair shaft of its colour; the amount of hydrogen peroxide you use on your hair will determine how "blond" you go. Hydrogen peroxide is actually not a very nice chemical at all (the materials safety data sheet for hydrogen peroxide says it can cause serious burns), so wear gloves and be careful when using it! Thanks for playing this quiz; I hope you enjoyed it.