Things I have learnt in chemistry

In preparation for my masters in Forensic Informatics I decided to read an AS and A-Level Chemistry book. Only GSCE knowledge of chemistry is needed (which is as far as I got with the subject), but the masters in Forensics (which I will be sharing half the courses with) require A-Level chemistry and a degree with some chemistry in it such as chemistry, biochemistry or chemical engineering. This seems a little weird, so I thought I’d read the book in case they expect me to actually remember anything I was taught 7 years ago. Here are a couple of interesting things I found in the book:

Ethene makes things get riper quicker

Fruit give off ethene, and the riper the fruit the more ethene they produce. Ethene also makes things ripen quicker, so a chain reaction happens when some fruits become riper quicker than others, promoting the others to also ripen quicker. Therefore, unripe mangos and other fruits bought at supermarkets should be placed next to ripe bananas to help them on their way. The same applied to green tomatoes when put with red ones in a dark cupboard. More on Ethene

How caffeine is taken out of coffee

Carbon dioxide when above a certain temperature (31deg c) and above a certain pressure (74atm) becomes a supercritical fluid where the distinction between fluid and gas disappears. In this state it is a solvent which can decaffeinate coffee beans. More on supercritical CO2

Breathalyser tests

Breathalyser tests have potassium dichromate crystals which are orange. If a lot of ethanol (alcohol) is added, they turn green/blue. More on breathalyser tests

Chanel number 5

Is known to chemists as CH3(CH2)8CHCH3CHO (2-methylundecanal) and is related to Formaldehyde. More on 2-methylundecanal

How Perms work

Hair protein owes its texture to the protein cystine which has bonds between the sulphur atoms. When hair is soaked in a gentle reducing agent, the S bonds are broken to form SH groups. While the hair is no longer linked, they are arranged in curls. Re-oxidation by soaking hair in a mild oxidising agent reforms the S bonds and holds the hair in its new configuration. More on Perms

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