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May 14 2012 1 14 /05 /May /2012 12:47

I have compiled a list of sources for the elements that are available to the amateur chemist. Lead will be discussed here.   

 

Lead is a soft blue-gray metal well known for its rather high density, although a significant number of elements exceed the density of lead. Lead is rather inert to many corrosive substances such as hydrochloric and sulfuric acid, but vulnerable to others like acetic acid. Soluble lead compounds are mostly colorless, while the insoluble ones can be either colorless (lead carbonate) or colorful (lead iodide). Lead is one of the few elements that forms insoluble halides. Lead chloride can be dissolved in hot water, while lead bromide is pale white like silver bromide and lead iodide is bright yellow, much brighter than silver iodide. All of them can dissolve to a significant extent in hot water. Lead has a low melting point and is easy to extract and shape, making it the ideal metal for many applications. However, its toxicity is necessitating a replacement of lead by other elements such as bismuth, which are more expensive, less dense, and more brittle. The banning of lead pellets for shooting of birds in wetlands is one such example. Lead forms a sulfide ore that forms large cubic crystals, known as galena. Lead also forms cerussite, which is lead carbonate and was used as a white pigment for many years. Crocoite, lead chromate, is a bright red mineral that was also used as a pigment until it was discontinued.

 

In element form: Lead fishing sinkers, bullets, and wheel weights are still relatively common. Lead acid batteries contain spongy lead metal on the anode. Tin-lead solder can be dissolved in hydrochloric acid, leaving lead behind.

 

In compound form: Lead white pigment contains lead carbonate. Lead glass contains lead silicate. Lead acid batteries have lead dioxide cathodes. Piezocrystals can have lead titanate or lead zirconate titanate in them.

 

Here is my sample of lead. It is a wheel weight containing about 95% lead.

 

Wheel weight

 

 

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