Other than monodisperse polymers, there is normally a molar mass distribution caused by chains of different length. Bonus: Use your free doubt session & get a free formula book! Repeating units can also be made from two monomers. Polymers are large molecules that have the same structural unit repeating over and over. From Table 14.5, the acrylonitrile repeat unit contains 3 Carbon atoms, 1 Nitrogen atom and 3 Hydrogen atoms. units. Ethanol and methanol are not very hydrocarbon-like and are not good solvents for polystyrene. Thus, the molecular weight of the acrylonitrile repeat unit is: The squiggly lines indicate that the polymer molecule extends further at both the left and right ends. A single molecule of polystryene has the repeating unit -[CH2CH(C6H5)]n-, where n is the number of repeating units. Join. Questions of this type are frequently asked in competitive entrance exams like Engineering … When the polymer is formed, the C=C double bond in the monomer is replaced by a C-C single bond in the polymer repeat unit, which links by two new bonds to adjoining repeat units. n is usually between 2,000 and 100,000 units. All you need to do to show any repeat unit is break the double bond, show where new bonds will form if the molecule reacts with another monomer and then put a bracket around that part. 1. Discover (and save!) "Mer" originates from the Greek word "meros," which means a part. polystyrene, from Table 5.3, each repeat unit has eight carbons and eight hydrogens. The two repeat units in this co-polymer are acrylonitrile and butadiene. I'm given the structure, and I have to count all the elements in the structure. For example, in polyethylene terephthalate (PET or "polyester"), the repeat unit is -CO-C6H4-CO-O-CH2-CH2-O-. B) Compute the number-average molecular weight for a polystyrene for which the degree of polymerization is 25,000. constitutes the repeating units. The molecular weight of a repeating unit, Mo= (12 x 2 + 1 x 4) g/ mol = 28 g/mol ... (polyvinyl chloride), styrene (phenylethylene, polystyrene), methyl methacrylate (Plexiglas), and acrylonitrile (cyanoethylene, acrylic fibers). A single molecule of polystryene has the repeating unit -[CH 2 CH(C 6 H 5)] n-, where n is the number of repeating units. A polystyrene-based resin foam body according to claim 8, wherein said polymer is selected from the group consisting of a homopolymer comprised of as a repeating unit acrylic acid, methacrylic acid or a derivative thereof; a copolymer comprised of as repeating unit acrylic acid, methacrylic acid or a derivative thereof; a copolymer comprised of as repeating unit vinyl alkylate; and a copolymer … Trending questions. Ethylene molecules are essentially composed of two methylene units (CH 2) linked together by a double bond between the carbon atoms—a structure represented by the formula CH 2 =CH 2. In this case the repeat unit has the same atoms as the monomer vinyl chloride CH2=CHCl. There are usually between 104 to 106 repeating units in a chain C C C C C C CH3 H H H CH3 H H H CH3 H H H be able to recognise the repeating unit in a poly(a lkene) Poly(a lkenes) like alkanes are unreactive due to the strong C-C and C-H bonds Monomer Polymer n ... Poly(phe nylethene) also known as polystyrene C C H H H phenylethene The phenyl group is -C6H5 See chapter 6.9 on … Chemistry; Thread starter AndrewDe; Start date Sep 27, 2017; Sep 27, 2017 #1 AndrewDe. The difference C p – C v was calculated at 273°K. In your answer you should explain why the polymers formed in these two reactions are different. The polymer is formed by the condensation reaction of the two monomers terephthalic acid (HOOC-C6H4-COOH) and ethylene glycol (HO-CH2-CH2-OH), or their chemical derivatives. The numbers preceding the poly prefix designate the first and last carbon atoms of the backbone repeating unit. For polystyrene, from Table 14.3, each repeat unit has eight carbons and eight hydrogens. Polymer molecules are very large compared with most other molecules, so the idea of a repeat unit is used when drawing a displayed formula. Although we commonly like to draw the structure of polystyrene as the isotactic structure because it is easy to see the repeating units, in fact, when styrene monomers are polymerised very little of the resulting polystyrene is in the isotactic form. B) 1.644 10 8 units. constitutes the repeating units. The brackets contain the repeating unit. Polystyrene is made from the monomer styrene which is a liquid petrochemical. We can deduce the structrure of the monomers by imagining the compounds which might be used to make the amide group. When drawing one, you need to: See the answer. Answer with step by step detailed solutions to question from Arihant's BITSAT Prep Guide, Polymers- "Repeating unit of polystyrene is" plus 6299 more questions from Chemistry. Repeating Unit Of Polystyrene. Repeating units can also be made from two monomers. For polyethylene, arguably the simplest polymer, this is demonstrated by the following equation. The examples of homopolymer are: polystyrene, polyethylene, polyvinyl chloride.. A copolymer consists of two or more different monomers as repeating units, such as the diblock copolymer: and the random or static copolymer: An example is the polystyrene-poly(methyl methacrylate) copolymer. constitutes the repeating units. (b) A simplified representation of polyvinyl acetate. D) 2.047 10 4 units. 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