The Very Beautiful Chemistry Quiz

Answer: Ammonium lauryl sulphate

Ammonium lauryl sulphate is a kind of chemical known as a surfactant. Surfactants are molecules made up of a long hydrocarbon tail joined to a charged "head". This structure means that surfactants are excellent at removing grease and dirt; the hydrocarbon tails of many ammonium lauryl sulphate molecules surround the grease particle leaving the charged heads on the outside.

The charge on the outside of this surfactant ball (known as a micelle) allows it to be washed away by water, taking the grease with it.

Answer: Calcium carbonate

Although most toothpastes contain a surfactant (such as ammonium lauryl sulphate mentioned in question 1) to make them foam up nicely, a surfactant is not considered to be the most important component of a good toothpaste. The most important component of toothpaste is an abrasive that grinds away any plaque, while not grinding away at the tooth's enamel. Calcium carbonate (CaCO3 - limestone!) is one of the abrasives used; others include magnesium carbonate (MgCO3), aluminium hydroxide (Al(OH)3) and calcium pyrophosphate (Ca2P2O7).

Answer: To harden the enamel of my teeth.

These days, many toothpastes contain fluoride, often as sodium fluoride (NaF). Other sources of fluoride in toothpaste are stannous fluoride (SnF2) and sodium monofluorophosphate (Na2PO3F). This additive is present only in small amounts (my toothpaste is 0.22% sodium fluoride), but it plays a major role in keeping teeth healthy.

The enamel covering our teeth is mostly made up of hydroxyapatite (Ca10(PO4)6(OH)2). Fluoride in toothpaste is thought to strengthen the enamel by replacing some of hydroxyapatite's OH groups with fluoride ions, to give fluoroapatite, which is stronger and resists acid wear better than the original hydroxyapatite.

Answer: Aluminium chlorohydrates

Aluminium chlorohydrates (such as Al2(OH)4Cl2 and Al2(OH)5Cl) are excellent at controlling perspiration. They do this by releasing aluminium ions, which close the ducts of the eccrine glands (the source of perspiration). Aluminium chlorohydrates also reduce the odor associated with the substances produced by another set of glands - the apocrine glands (while the substances produced by these glands are odourless, the substances themselves encourage bacterial growth, which is where the odour comes from).

Answer: Mica

Mica is an aluminosilicate mineral containing aluminium, silicon and oxygen atoms. It is a shiny solid, and can be easily cleaved into thin, translucent sheets. This is possible because the atoms that make up mica are arranged in sheets, much like the sheets of carbon that make up graphite. Finely-crushed mica is added to make-up preparations such as eye shadow, lip gloss, lipstick and bronzing powders to give them "sparkle".

Answer: Iron oxides

Iron oxides can be varying shades of brown, yellow and orange. They are finely crushed and added to eye shadow to give it colour. Other colouring agents used in eye shadow are carbon black (which is a finely crushed material very similar to charcoal) and ultramarine blue. Titanium dioxide (TiO2) is also used in eye shadow as a base, as it is an opaque, bright white, which, when mixed with a pigment, allows the product to be applied without having the colour of the skin underneath showing through.

Answer: Castor oil

Castor oil can be obtained from plant seeds. In general, it is a mixture of triglycerides, but before being used in the cosmetics industry, it must be highly purified. Only a small percentage of the weight of a tube of lipstick is taken up by the dye that gives it its colour. Castor oil and other emollients in lipsticks such as lanolin and waxes help keep the lips soft.

Answer: A hydrated magnesium silicate.

Like mica, the atoms that make up talc are arranged in sheets; talc feels slippery because these sheets can easily move over each other. Finely-crushed talc is used in face powders as a bulking agent and also to give a pleasant texture to the preparation. Face powders also contain ingredients such as kaolin, which helps to absorb moisture.

Answer: Sodium chloride

Linalool is a substance present naturally in lavender that gives it its glorious smell. Geraniol is the compound responsible for the scent of a rose; it can also be extracted from geranium plants, from which its name is derived. Citronellol provides a beautifully light citrus-lemon scent. Limonene is another citrus fragrance, and can be isolated from the skins of oranges.

Answer: Vitamin E

Vitamin E (also known as alpha-tocopherol, which is the most active form of vitamin E in humans) is a good antioxidant because it reacts very readily with a certain class of chemical compound called radicals. Radicals contain a single unpaired electron and as a result are very reactive.

It is thought that radicals cause cell damage, which can lead to wrinkles. Vitamin E can be obtained naturally by eating foods such as nuts and green leafy vegetables. Another well-known antioxidant is vitamin C, which is a popular dietary supplement. Well, I'm ready to face the day now - thanks for playing!