The chemistry of the environmental effects of fireworks

Who doesn’t love fireworks at New Year? Yet whilst fireworks are undoubtedly a spectacle, they can also have a negative effect on the environment. Take a look at the graphic below, to discover some of the issues that they can cause.

Source: Compound Interest

So that’s the science, but what about the history? Who first invented the firework?

The earliest documentation of fireworks dates back to 7th century China (time of the Tang Dynasty), where they were invented. The fireworks were used to accompany many festivities. It is thus a part of the culture of China and had its origin there; eventually it spread to other cultures and societies.

The art and science of firework making has developed into an independent profession. In China, pyrotechnicians were respected for their knowledge of complex techniques in mounting firework displays. Chinese people originally believed that the fireworks could expel evil spirits and bring about luck and happiness.

During the Song Dynasty (960–1279), many of the common people could purchase various kinds of fireworks from market vendors, and grand displays of fireworks were also known to be held. In 1110, a large fireworks display in a martial demonstration was held to entertain Emperor Huizong of Song (r. 1100–1125) and his court. A record from 1264 states that a rocket-propelled firework went off near the Empress Dowager Gong Sheng and startled her during a feast held in her honor by her son Emperor Lizong of Song (r. 1224–1264). 

Rocket propulsion was common in warfare, as evidenced by the Huolongjing compiled by Liu Bowen (1311–1375) and Jiao Yu (fl. c. 1350–1412). In 1240 the Arabs acquired knowledge of gunpowder and its uses from China. A Syrian named Hasan al-Rammah wrote of rockets, fireworks, and other incendiaries, using terms that suggested he derived his knowledge from Chinese sources, such as his references to fireworks as "Chinese flowers".

With the development of chinoiserie in Europe, Chinese fireworks began to gain popularity around the mid-17th century. Lev Izmailov, ambassador of Peter the Great, once reported from China: "They make such fireworks that no one in Europe has ever seen." In 1758, the Jesuit missionary Pierre Nicolas le Chéron d'Incarville, living in Beijing, wrote about the methods and composition on how to make many types of Chinese fireworks to the Paris Academy of Sciences, which revealed and published the account five years later. His writings would be translated in 1765, resulting in the popularization of fireworks and further attempts to uncover the secrets of Chinese fireworks.

For more information visit:-

http://www.compoundchem.com/2017/01/05/fireworks-environment/

https://en.wikipedia.org/wiki/Fireworks

http://www.prlabs.co.uk/lab-supplies.php?N=lead-1000ppm-for-icp&Id=60146

Polish that Chrome!

Chromium is the first of the group 6 transition metals. It is denoted by the symbol Cr and atomic number 24. Chromium is a grey coloured, hard and very lustrous metal.  It takes a high polish, resists tarnishing, and has a high melting point. The name of the element is derived from the Greek word "chrōma" (χρώμα), meaning colour.

Chromium is highly corrosion resistant, a character that it brings with it when added to steel to create stainless steel. Another popular use for chromium is electroplating, which gives hubcaps, bumpers and other shiny bits of cars their street-cred.

Many of its compounds are intensely coloured. Besides providing the familiar non-fading "chrome yellow" colour used on American school buses and by the German postal service, there is the bright red pigment, chrome red (PbCrO₄·Pb(OH)₂), a bright green (Cr₂O₃), a pale green ([CrCl(H₂O)₅]Cl₂), and rich violet ([Cr(H₂O)₆]Cl₃). Trace amounts of chromium also gives rubies and emeralds their characteristic colours.

Below is the relatively rare mineral, crocoite (PbCrO₄), the state mineral of Tasmania.

Chromium is the 24th most abundant element in Earth's crust with an average concentration of 100 ppm. Chromium compounds are found in the environment, due to erosion of chromium-containing rocks and can be distributed by volcanic eruptions. The concentrations range in soil is between 1 and 300 mg/kg, in sea water 5 to 800 µg/litre, and in rivers and lakes 26 µg/litre to 5.2 mg/litre.  Chromium is mined as chromite (FeCr₂O₄) ore.  About two-fifths of the chromite ores and concentrates in the world are produced in South Africa, while Kazakhstan, India, Russia, and Turkey are also substantial producers. Untapped chromite deposits are plentiful, but geographically concentrated in Kazakhstan and southern Africa

In the laboratory Chromic acid is a powerful oxidizing agent and is a useful compound for cleaning laboratory glassware of any trace of organic compounds. It is prepared in situ by dissolving potassium dichromate in concentrated sulfuric acid, which is then used to wash the apparatus. Sodium dichromate is sometimes used because of its higher solubility (50 g/L versus 200 g/L respectively). The use of dichromate cleaning solutions is now phased out due to the high toxicity and environmental concerns. Modern cleaning solutions are highly effective and chromium free. Potassium dichromate is a chemical reagent, used as a titrating agent. It is also used as a mordant (i.e., a fixing agent) for dyes in fabric.

For more information visit:-
http://www.theguardian.com/science/punctuated-equilibrium/2011/aug/12/1?guni=Article:in%20body%20link
http://en.wikipedia.org/wiki/Chromium