Happy Chinese New Year (CNY, Lunar Calendar) …or .. Year of the Horse.
1. What’re related to Chemistry? – as said, you don’t need a book to revise Chemistry. Because chemistry is all around us — even inside us as most of our body are made up of C, H, O, N, … and bits of P, S, and metals (e.g. Ca in our bones, Fe in our blood [makes it red due to Haemoglobin], Na+ & K+ ions in our blood [blood pressure control], etc… ).
2. So, what do you do in Chinese New Year? Lots of food, drinks, fun, …. and their chemistry!
2a.) Explosives only ? – First must be the expected “explosive plays” – the fireworks, firecrackers, pop-ups, … and all sorts of party things. Most fireworks are explosives and should be handled with great care. Sad news already appeared in news when people played without safety precautions. Apart from that, air pollution is another undesirable results of playing such. WHY? This leads to the need for understanding “what explosion is”.
Actually, explosions could be brought about by TWO methods: (1) chemical reactions that gives out a lot of gases from solid mixtures when burnt. (2) by sudden change of pressure – pressure change, … could be simply done by piercing through a balloon.
(2) is easily explained. For (1), you need to know the details of the reactions inside. Two of such reactions are from the potassium compounds (nitrate and chlorate): (i) 2 KNO3 (s) —> K2O (s) + N2 (g) + 2.5 O2 (g) and (ii) 2 KClO3 (s) —> 2 KCl(s) + 3 O2(g) ….. BOTH give larger amount of gases from solid which create sudden change of volume (also due to heat evolved) and hence sudden “BANG”!!! Also, that involves some reaction types: “decomposition” (breakdown); ”redox reactions” (oxidation & reduction, by HEAT!)
Another results of fireworks is “visual” colours — which you could easily checked by burning group I compounds (LiCl, NaCl, KCl, …. ) – giving red, yellow, purple, … colours. This is also a famous tests for such compounds, by “Flame Test” (not a reaction). And, the study of such originates from a famous scientist “Bunsen” – YES, the scientist that modified the “Bunsen Burner”.
2b.) How about other party stuff? – some “explosions” do not contain explosives. That works by “air pressure”. Another one is by the unstable nature of “phosphorus”, which is also an element in our matches — when strike or rub on the ground, it “explodes”! Furthermore, there are colorful “plastic sprays” — actually a polymer that turns the molecules into chains of it when it meets air. Also, there are fluorescent lights — containing chemicals that react to give such “coloured lights” when the inside tube breaks and the chemicals mix to react.
2c.) FOOD ? – of course, all food are some kind of chemicals. What we specially eat in CNY are “fried snacks”, “cakes of diff styles”, etc …
2d.) Red-packs ? – related to Chem? Yes! While most red-packs are in paper form, some are plastic. Even the money could be plastic ! So, plastic is surely a chemical (called polymer) that is made from simple small molecules. BUT, remember that most green activists consider plastic as NOT environmental. What do you think? Will you reject plastic money? :):)
2e.) ??? …. Surely, you can name MANY more in your holiday visits and fun meetings with your friends and relatives.
Have fun and learn something (by way of thinking & association) in your CNY