The Interdisciplinary Laboratory

 Pre-Lab Assignment for Experiment #2:
Molecular Weight of Macromolecules



The following flow times were recorded for several aqueous solutions of polystyrene.
 
 

concentration (g/100mL) flow time(s)
0.836 135.7, 134.7, 134.8, 136.4
0.627 112.4, 112.9, 112.9
0.401 94.0, 92.2, 92.5, 92.6
0.287 83.6, 83.6, 83.8
pure water 63.63

The average flow time for solvent water is 66.08 +/- 0.09 s.  Calculate the average flow time and its standard deviation for each concentration.  Calculate the reduced viscosity of this polymer in water solvent and from the extrapolation determine the intrinsic viscosity.  What are the units of intrinsic viscosity?

Submit via e-mail the solutions to this pre-lab assignment (the average flow time and its standard deviation for each concentration, the relative viscosity, and the magnitude and units of intrinsic viscosity) to Professor Cave (Robert_Cave@hmc.edu) by 8 p.m. on the Monday evening prior to your first laboratory day (i.e., Monday, September 4 or Monday, October 2).  Turn in any graphs prepared to answer these questions at the beginning of class on Wednesday, September 6 (or Wednesday, October 4).