Question 77 - The molecular weights M in kg / mol of 3 different monomers a, b and c in a polymer are Ma = 14, Mb = 16 and Mc = 18, with their respective quantities in N units having the ratio of Na : Nb : Nc = 2 : 3 : 5. (a) Find the numerical average molecular weight of the polymer by using the formula (Ma Na + Mb Nb + Mc Nc) / (Na + Nb + Nc). (b) Find the weighted average molecular weight of the polymer by using the formula (Ma Na Ma + Mb Nb Mb + Mc Nc Mc) / (Ma Na + Mb Nb + Mc Nc). (c) Calculate the polydispersity Q by using the answer in (b) divided by answer in (a). (d) Find the volumetric average molecular weight of the polymer by using the formula (Ma Na Ma Ma + Mb Nb Mb Mb + Mc Nc Mc Mc) / (Ma Na Ma + Mb Nb Mb + Mc Nc Mc). (e) Estimate the polydispersity Q by using the answer in (d) divided by answer in (b).
- 1 Answers
- 1593 Views
- I also Faced
- E-Mail Answers
Answer Posted / kang chuen tat (malaysia - pen
Answer 77 - (a) Numerical average molecular weight = (Ma Na + Mb Nb + Mc Nc) / (Na + Nb + Nc) = (14 x 2 + 16 x 3 + 18 x 5) / (2 + 3 + 5) = 166 / 10 = 16.6 kg / mol. (b) Weighted average molecular weight = (Ma Na Ma + Mb Nb Mb + Mc Nc Mc) / (Ma Na + Mb Nb + Mc Nc) = (14 x 2 x 14 + 16 x 3 x 16 + 18 x 5 x 18) / (14 x 2 + 16 x 3 + 18 x 5) = 2780 / 166 = 16.747 kg / mol. (c) Polydispersity = [ answer in (b) ] / [ answer in (a) ] = (16.747 kg / mol) / (16.6 kg / mol) = 1.0089. (d) Volumetric average molecular weight = (Ma Na Ma Ma + Mb Nb Mb Mb + Mc Nc Mc Mc) / (Ma Na Ma + Mb Nb Mb + Mc Nc Mc) = (14 x 2 x 14 x 14 + 16 x 3 x 16 x 16 + 18 x 5 x 18 x 18) / (14 x 2 x 14 + 16 x 3 x 16 + 18 x 5 x 18) = 46936 / 2780 = 16.883 kg / mol. (e) Polydispersity estimation = [ answer in (d) ] / [ answer in (b) ] = (16.883 kg / mol) / (16.747 kg / mol) = 1.0081. The answer is given by Kang Chuen Tat; PO Box 6263, Dandenong, Victoria VIC 3175, Australia; SMS +61405421706; chuentat@hotmail.com; http://kangchuentat.wordpress.com.
| Is This Answer Correct ? | 0 Yes | 0 No |
Post New Answer View All Answers
What is the ignition temp. of Aluminum,Coper&Iron.
How much water is lost through a commercial cooling tower system with a throughput of about 600 gpm?
What is the most common cause of solid size segregation in bulk solid systems?
Explain how can you keep our seawater used for heat rejection clean before entering our heat exchangers?
What is screen analysis and what are its applications in the chemical industry?
i want sample inteview question of chemical engg for BARC
Repected sir/Madam, I am goingb to face IOCL technical as well as HR interview, can you forward your hellpfull hand for toward me to sort out my problem by giving some imp interview quetion which is generally asked in chemical industries such like IOCL,HPCL,ONGC,BPCL,RIL,etc I will always thankfull to you,for sharing your profficient knowledge with me and making me somewhat technically sound
What are the design considerations for a piping system for the transfer of slurries?
How can one estimate how the friction factor changes in heat exchanger tubes with a change in temperature?
Please colleagues I need to choice a proper hopper shape for a Fertilizer bulk blender flowing throut a high humidity raw material like zeolite, so we are in doubt whether use squard or rectangular hopper shape to avoid the so call voul effect that can create obstruction
What are some good tank mixing rules of thumb?
What is a good approximation for the heat transfer coefficient of hydrocarbons inside 3/4" tubes?
What are the advantages of using gear pumps?
Why in a continuous plant for a Hot standby screw pump system the interlock for auto starting of the other pump ( when the running pump stopped suddenly) is given with header pressure only? why not with flow rate or current of the pump?
Explain the difference between cfm (cubic feet per minute) and scfm (standard cubic feet per minute)?
