11/15/2023 0 Comments Viscosity chemistry vocabulary pdf![]() ![]() ![]() The video below shows several different long chained oils, each progressively more viscous. Glycerol, CH 2OHCHOHCH 2OH, is viscous partly because of the length of the chain but also because of the extensive possibilities for hydrogen bonding between the molecules. Fuel oil, lubricating grease, and other long-chain alkane molecules are quite viscous for this reason. The McGraw-Hill Dictionary of Chemistry provides a compendium of 8000 terms that are central to chemistry and related fields of science and technology. How easily a liquid flows is related to its chemical structure, including. In other words a plot of shear stress versus shear strain rate is linear. viscosity, resistance of a fluid (liquid or gas) to a change in shape, or movement of neighbouring portions relative to one another. A liquid with low viscosity, for example, cooking oil will flow quickly and easily. This is because the molecular chains get tangled up in each other like spaghetti-in order for the liquid to flow, the molecules must first unravel. A Newtonian fluid is one in which the viscosity is independent of the shear rate. Liquids containing long molecules are invariably very viscous. ![]() Honey, mostly glucose and fructose (see image below) is a good example of a liquid which owes its viscosity to hydrogen bonding. Most ordinary liquids have viscosities on the order of 1 to 1000 mPa s, while gases have viscosities on the order of 1 to 10 Pa s. The bottom line is to come up with ways to measure viscosity so that you can quantify whether a material will flow the way it needs to. For handlers of all materials that flow, either while being processed or in an end-use, it is important to think about the materials’ flow characteristics. The viscosity of water at 20 ☌ is 1.0020 millipascal seconds (which is conveniently close to one by coincidence alone). Computation: Where: 1 viscosity of the unknown 1 density of the unknown t1 flow time in seconds of the unknown 2 viscosity of water at 25 ☌ (0.8904 cps) 2 density of water at 25 ☌ (0.997 g/ cm3) t1 flow time in seconds of water at 25 ☌ (100sec) Questions: Answer the following and cite your references. To be brief, viscosity is resistance to flow. Liquids whose molecules are polar or can form hydrogen bonds are usually more viscous than similar nonpolar substances. Viscosity is first and foremost a function of material. Neutral oils: unfiltered lubricating oils of low or medium viscosity obtained in petroleum distillation and prepared without chemical treatment they are so. Viscosity is governed by the strength of intermolecular forces and especially by the shapes of the molecules of a liquid. Those like ether or gasoline which flow very readily have low viscosities. Liquids which flow very slowly, like glycerin or honey, have high viscosities. The resistance to such flow is called the viscosity. \)īecause its molecules can slide around each other, a liquid has the ability to flow. ![]()
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