Distribution equilibrium

Article no. P3030701 | Type: Experiments

10 Minutes
20 Minutes
University
Teachers/Professors , Students
medium

Principle

At constant temperature and under constant pressure, a dissolved substance distributes itself between two immiscible liquids in a constant concentration ratio. This ratio is equal to the partition coefficient (distribution coefficient) of the substance examined in the given two-phase system.

Benefits

  • Modern, easy-to-use photospectrometer

Tasks

  1. Measure the extinction of various concentrated solutions of trans-azobenzene in acetonitrile at constant wavelength. Subsequently determine the equilibrium concentrations (extinctions) of trans-azobenzene in the system n-heptane / acetonitrile after single and repeated distribution at constant temperature.
  2. Calculate the partition coefficients and effectiveness of the extractions from the experimental data and compare them.

Learning objectives

  • Principles of thermodynamics
  • Partial molar free enthalpy (chemical potential)
  • Equilibrium between phases
  • Distribution and extraction
  • Nernst distribution equation
  • Lambert-Beer law
  • Photometry

Necessary accessories

  • Precision balance 620g/0.001g

 

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Article no. 36589-00
1
Article no. 36592-00
1

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Digital learning
(en) Experiment guide
p3030701e .pdf
File size 0.50 Mb
pdf
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