01Sep 2016 by Vincent Summers 1 Comment

Acids, Bases, Salts: Can An Oxide Be A Salt?

Chemistry, Education
[caption id="attachment_15469" align="alignright" width="440"] Aluminum chloride, hexahydrate. - Image Victor Claessen CC-SA 3.0.[/caption] Acids, bases, salts: Can an oxide be a salt? Let’s find out. Combine an acid and a base and you often get back a salt and water. This should be no surprise. It is high school chemistry. Assume we have a most simple acid, H-A. Too, we have a most simple base, B-OH. If we react the two, we expect the reaction mechanism to be written, H-A + B-OH → B-A + H2O H2O is, of course, water. B-A is the expected salt. Is An Oxide a Salt? Let us consider an example that deviates from the above simple concept—aluminum. Metals tend toward cationic (+) behavior. Non-metals act in opposite fashion, tending toward anionic (-) behavior. Aluminum…
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13Nov 2015 by Vincent Summers No Comments

Aluminum Was a Precious Metal

Chemistry, Technology
[caption id="attachment_10187" align="alignright" width="440"] Bas-relief aluminum door in the Hunt Library.[/caption] Various materials and artifacts bring a high price. This is because of their beauty, low availability, or craftsmanship. Some desirable objects are so rare we consider them precious. These include platinum, silver, and gold. But not aluminum. Yet during the 19th Century this bright and shiny metal was highly valued. How can that be so? Aluminum Deposits It is the most common metal in earth. It is not especially beautiful. So why did the metal once bring so high a price? In a sense it was scarce. It was unavailable. Availability [caption id="attachment_20663" align="alignright" width="200"] 1893 cast aluminum angel statue, Piccadilly Circus, London - Image by Michael Reeve[/caption] Diamonds are highly prized. Yet, they are fairly common. The number…
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11Jun 2012 by Vincent Summers 3 Comments

Aluminum Foil: One Shiny Side?

Manufacturing
[caption id="attachment_2492" align="alignright" width="440"] Aluminum Foil[/caption] Ever wondered why ordinary household aluminum foil comes with a shiny side and a dull or matte side? Think maybe there’s some special reason for a shiny side? Or for the matte side? Life is complex — but aluminum foil is not. Here’s the explanation. Made from Sheet The metal foil is made by repeatedly thinning metal sheet — finer and finer — using highly polished rollers. It is possible to do this only to a point. That point is just slightly before reaching the desired thickness. Although it is possible to obtain the foil that is shiny on both sides, that foil would not be thin enough for practical, inexpensive use. Two are Better Than One If manufacturers tried to continue the process…
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