MULTIPLE CHOICE QUESTIONSChapter 11. I mentioned in class that you don’t need to know the difference between a racemic and mesodiad. I lied!Alright, I suppose that’s not fair. Below is figure 1.5 from the book, showing these diads. Figure 1.5 Schematic diagram depicting racemic and meso diadsAn NMR analysis of a polystyrene sample showed that it had close to 100% racemic diads.the sample would beA. Isotactic polystyreneB. Syndiotactic polystyreneC. Atactic polystyrene2. A second sample had about 50% meso diads and 50% racemic. What is the most probabletacticity of this sample (A – C in Q1).3. This polystyrene has a number average molecular weight of 100,000 and a polydispersity of5. What is the weight average molecular weight?A) 20,000B) 100,000C) 500,000D) 100,005E) 5,000,000meso diad mracemic diad r4. Consider the following copolymersA. (B–B–B - - - B–B) (A–A–A - - - - A–A) (B–B - - - - B–B–B)~5% ~90% ~5%B. A–A–A - - - - A–A – B–B - - - - B–BC. – – A – B – A – A – B – B – A – A – A – B – A – B – B – –D. – A – B – A – B – A – B – A – B – –E. – – A – A – A – A – A – A – A – A – – –| | |B B B| | |B B B| | |B B B' ' '' ' '' ' '' ' 'B B BWhich of these is a triblock copolymer?5. Consider the properties of the following two polyethylene samples. Sample 1 was producedby a high pressure process while sample 2 was synthesized using a catalyst.Polyethylene 1 Polyethylene 2Mol wt. 200,000 200,000Density (g/cm3) 0.92 0.96Crystalline melting pt. 108°C 133°CStiffness (lb/in2x103) 25 125Hardness (Shore D) 45 65Which of the following statements is true?A. Sample 2 is more branched than sample 1B. Sample 1 is more branched than sample 2C. Sample 1 is more atacticD. Sample 1 is more isotacticE. Painter shouldn't set such easy gift questions6. Which of these do you think would be more appropriate for use in making bottles fordetergent?A. Sample 1B. Sample 27. Which would make a better film for wrapping up leftover food? (A or B in Q6).8. Which of the following polymers is least likely to be optically transparentA. Atactic polystyreneB. Isotactic polystyreneC. An ethylene/propylene random copolymer (50/50 composition)D. A styrene/butadiene random copolymer9. Consider the following copolymersA. {Styrene}-{butadiene}-{Styrene} triblock copolymer (10%; 80%; 10%)B. A cross-linked styrene/butadiene random copolymer (20%/80%)C. A 50/50 ethylene/propylene random copolymer (also cross-linked)D. A 50/50 ethylene (linear)/atactic polypropylene block copolymerWhich of these copolymers is likely to have at least some crystallinity?10. A sample of atactic polystyrene is separated into 5 fractions;Fraction Number of Moles Molecular Weight1 20 10,0002 20 20,0003 20 30,0004 20 40,0005 20 50,000What is the number average molecular weight?A. 2.33 x 104B. 3.0 x 104C. 3.66 x 104D. 4.33 x 10411. What is the weight average? (A – D in Q10).12. What is the polydispersity?A) 1B) 2C) 1.22D) 1.44Chapter 21. Styrene is almost a unique monomer, in that it can be polymerized by practically all methodsof chain polymerization.A. Free radicalB. AnionicC. CationicD. Co-ordination (i.e., with a catalyst)Which of these methods would you use to make isotactic polystyrene?2. If you needed to synthesize a set of narrow molecular weight standards (i.e., withpolydispersities close to 1), which of the above methods would you use?3. Commercial atactic polystyrene is synthesized by which of the above methods?4. What method would you use to synthesize a triblock copolymer?A) Free radical polymerizationB) Anionic polymerizationC) Using a Ziegler Natta catalystD) By putting it into a bloody great pot and spitting on it to initiate polymerizationE) Condensation polymerization5. Suspension free radical polymerization of styrene would be preferred over bulkpolymerization to overcome the problem ofA) BranchingB) Cross-linkingC) Stereo-isomerismD) Polymeric impuritiesE) Temperature control during polymerization6. In emulsion polymerization, the principal place where the monomer polymerizes isA) Monomer dropletsB) Aqueous phaseC) Surfactant micellesD) Surface of reactorE) Air-liquid interface7. Polypropylene produced commercially using a Ziegler-Natta catalyst is predominantlyA) AtacticB) IsotacticC) Syndiotactic8. Consider the following monomers or pairs of monomers:A.and (phenol) (formaldahyde)B. andC.and (styrene) (butadiene)D.E. Which of the monomers (A-E) listed above gives a densely cross-linked network whenpolymerized under the appropriate conditions?7. Which of the above monomers is polymerized free radically at high pressures to give apolymer containing some short chain branches?8. Which monomers form a polyester?9. Which of the monomers containing a C = C double bond cannot be polymerized freeradically?10. Which monomers are used to make a thermoplastic rubber?OHCH2OHO - CH2 - CH2 - OHHO - CC - OHOO CH2 = CH CH2 = CH - CH =CH2 CH2 = CH2 CH3 CH2 = CH211. The method of polymerization used to make this rubber is:A. Free radicalB. AnionicC. Cationic14. Which pairs of monomers would you use to make an ethylene/propylene random copolymer?A. Pair (A) aboveB. Pair (B) aboveC. Pair (C) aboveD. Monomers (D) and (E) above15. Would you make this polymer using:A. Free radical polymerizationB. Anionic polymerizationC. Cationic polymerizationD. Using a catalyst (coordination polymerization)Chapter 31. In the steady state assumption the concentration of radical species is given byA. [M.] = [ f tdkk[I] ]2B. [M.] = [ f tdkk[I] ]C. [M.] = [ f tdkk [I] ]1/2D. [M.] = [ f dtkk [I] ]1/22. Accordingly, if we assume that the concentration of initiator remains constant the rate ofpolymerization is given byA. Rp = kp [f kd [I]kt ]1/2 [M]B. Rp = rp + ri = [ f kd [I]kt ]1/2 [M] + 2 f kd [I]C. Rp = -rt = 2kt [f kd [I]kt ]1/2D. Rp = [kp2(f kd kt)1/2 ] [M][I]1/2 4. AIBN is used to initiate the polymerization of methylmethacrylate in benzene at 60°C and[I]o = 0.02 mol/l[M]o = 2 mol/lAssuming f is 1, what is the initial rate of polymerization?[kp = 705, kt = 50 x 10-6, kd = 0.85 x 10-5, in appropriate units]NOTE, USEri = d[M.]dt = 2f kd [I]rp = - d[M]dt = kp [M.] [M]rt = - d[M.]dt = 2kt [M.] 2A. 82.2B. 4108.3C. 8216.7D. 11.64. What is the initial degree of polymerization? You can assume termination bydisproportionation