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.
Does aspirin contain sulfur? No, just carbon, hydrogen, and oxygen. Chemically, it's 2-acetoxybenzoic acid... the ester of salicylic acid and acetic acid (this is possible because salicylic acid has botâ¦h carboxylic acid and alcohol functional groups).