1 By convention a normal lens on a 35mm film camera (and thus a full-frame EOS digital SLR) has a focal length of 50mm or so. 2  A lens with a focal length of 35mm is considered ânormalâ for a cropped-frame EF-S camera.
Aspirin. One of the best known aromatic acetates is acetylsalicylic acid, or aspirin, which is prepared by the esterification of the phenolic hydroxyl group of salicylic acid. Aspirin possesses a number of properties that make it the most often recommended drug.
The Story of Aspirin: Chemical Structure. Acetylsalicylic acid âor, as it is more commonly. known, aspirin âhas a simple chemical structure. It consists of a small number of carbon, hydrogen. and oxygen atoms, that form the chemical. bonding patterns shown to the left and below. In the figures shown on. this poster, the colours. indicate the position of.