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.
CLASSIFICATION. GENERAL DESCRIPTION. Acetylsalicylic Acid, also known by trade name Aspirin, is an acetyl derivative of salicylic acid that is a white, crystalline, weakly acidic substance, with melting point 137Â°C. It is useful in the relief of headache and muscle and joint aches.LASSIFICATION. GENERAL DESCRIPTION. Acetylsalicylic Acid, also known by trade name Aspirin, is an acetyl derivative of salicylic acid that is a white, crystalline, weakly acidic substance, with melting point 137Â°C. It is useful in the relief of headache and muscle and joint aches.