Sunday, June 5, 2011

Pre-Research (Koh Su En)

Partition Coefficient:The partition coefficient is the equilibrium distribution of an analyte between the sample phase and the gas phase.

Equilibrium (Chemistry) is a state in which a process and its reverse are occurring at equal rates so that no overall change is taking place.
eg. Ice is in equilibrium with water

Calculating Partition Coefficient:

Partition Coefficient (K) = Cs/Cg

where Cs is the concentration of analyte in sample phase;
C
g is the concentration of analyte in gas phase

Source: http://www.labhut.com/education/headspace/introduction03.php

an·a·lyte (n-lt)
n.
A substance or chemical constituent that is undergoing analysis.

Source: http://medical-dictionary.thefreedictionary.com/analyte

Polar and Non-Polar Compounds

Depending on the relative electronegativities of the two atoms sharing electrons, there may be partial transfer of electron density from one atom to the other. When the electronegativities are not equal, electrons are not shared equally and partial ionic charges develop.

The greater the electronegativity difference, the more ionic the bond is. Bonds that are partly ionic are called polar covalent bonds. (Refer to Picture 1.)

Nonpolar covalent bonds, with equal sharing of the bond electrons, arise when the electronegativities of the two atoms are equal. (Refer to Picture 1.)

Picture 1.

Source: http://users.stlcc.edu/gkrishnan/polar.html

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