What This Document Is
This document is a lab report detailing an experiment to determine the molecular weight of polystyrene using viscosity measurements. It outlines the theoretical background, experimental procedure, and likely results of a physical chemistry laboratory exercise. The core principle involves relating the viscosity of a polymer solution to its molecular weight, building upon Einstein’s initial work connecting viscosity to molecular characteristics.
Why This Document Matters
This report is valuable for students enrolled in an Introduction to Physical Chemistry Laboratory course (like East Carolina University’s CHEM 3851). It serves as a model for structuring and reporting experimental findings, demonstrating how to apply theoretical concepts to real-world measurements. Professionals in materials science, polymer chemistry, or related fields may find it useful as a reference for understanding viscosity-based molecular weight determination techniques. It’s particularly relevant when needing to understand the relationship between polymer properties and solution behavior.
Common Limitations or Challenges
This document focuses on a specific polymer (polystyrene) in a specific solvent (toluene) under controlled conditions. It does *not* provide a universal method for determining the molecular weight of all polymers. Users will still need to understand the underlying theory and adapt the procedure for different polymer-solvent systems. It also doesn’t cover error analysis in detail, or alternative methods for molecular weight determination.
What This Document Provides
The full document includes:
* A detailed introduction to the theory behind viscosity measurements and their relation to polymer molecular weight, referencing Einstein’s foundational work.
* Specific equations used to calculate molecular weight from viscosity data (including equations for specific viscosity and limiting viscosity number).
* A description of the experimental setup, including chemicals (toluene, polystyrene), equipment (viscometer, analytical balance, thermostat), and procedures.
* Figures illustrating the experimental apparatus (variable temperature thermostat and viscometer).
* A record of the experimental results and analysis performed by Ashlee Perkinson on March 19, 2012.
This preview provides a high-level overview of the experiment and its theoretical basis. It does *not* include the actual experimental data, calculations, or a complete discussion of the results.
