Question 75 - 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. The fraction of polymer chain X of 3 different monomers a, b and c in a polymer are Xa = 0.5, Xb = 0.3 and Xc = 0.2. (i) Calculate number average molecular weight by using the formula Ma Xa + Mb Xb + Mc Xc. (ii) Calculate weight average molecular weight by using the formula (Ma Xa Ma + Mb Xb Mb + Mc Xc Mc) / (Ma Xa + Mb Xb + Mc Xc). (iii) Calculate the polydispersity by using the answer in (ii) divided by answer in (i). (iv) If the molecular weight of repeat unit is 12, calculate the degree of polymerization by using the formula (Ma Xa + Mb Xb + Mc Xc) / (molecular weight of repeat unit).
Answer Posted / kang chuen tat (malaysia - pen
Answer 75 - (i) Number average molecular weight = Ma Xa + Mb Xb + Mc Xc = 14 x 0.5 + 16 x 0.3 + 18 x 0.2 = 15.4 kg / mol. (ii) Weight average molecular weight = (Ma Xa Ma + Mb Xb Mb + Mc Xc Mc) / (Ma Xa + Mb Xb + Mc Xc) = (14 x 0.5 x 14 + 16 x 0.3 x 16 + 18 x 0.2 x 18) / 15.4 = 15.558 kg / mol. (iii) Polydispersity = [ answer in (ii) ] / [ answer in (i) ] = 15.558 / 15.4 = 1.0103. (iv) Degree of polymerization = (Ma Xa + Mb Xb + Mc Xc) / (molecular weight of repeat unit) = (15.4 kg / mol) / (12 g / mol) = 1.283 k = 1283. 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 types of metals are typically removed via chemical precipitation?
what is the difference between car seal close/open valves and lock close/open valves?
What is the maximum recommend pipe velocity for dry and wet gases?
Hi.. Me going to tke test for management trainee(technical) Post I am an chemical engineering student . Can u guide how to prepare for this test.Can u send me test paper pattern..?
Explain what types of valves are recommended for slurry services?
Are some heat transfer services more prone to tube vibration that others for a shell and tube exchanger?
Explain what are the criteria involved in choosing mass balances for components?
Re: Sugar Cane Bagasse What are the 1. Specific Heat of Bagasse at 50% moisture, 40% moisture and 25% moisture? 2. What is bu;lk density of bagasse at 50% moisture, 40% moisture and 25% moisture? 3. What is specific gravity of bagasse at 50% moisture, 40% moisture and 25% moisture? 4. What is the specific heat of flue gases generated from boiler fuelled by bagasse? 5. What is the specific gravity of flue gases generated from boiler fuelled by bagasse?
Name some guidelines for designing for liquid and gas velocities in process plant piping?
What is the difference between horizontal and vertical heat exchanger?
can you explain about the design calculations and procedure of boiler
which reformer efficiencywise best?
Under what circumstances are vortex flowmeters the most accurate?
What is the best way to control an oversized, horizontally oriented shell and tube steam heater?
What are some of the consequences of an undersized kettle type reboiler?