LAB REPORT Example | Topics and Well Written Essays - 750 words

Lab Report Example The ultimate intention is to determine the polarity of these molecules based on the relative electro-negativities of the atoms relating to the molecular hence stating whether a molecule is either polar or nonpolar. It has been generally known that a non-polar solvent will often dissolve a nonpolar molecule but not a polar molecule. It is therefore to a large extent, necessary to understand the theory behind the polarity of a molecule. This information will be critical in making of prudent decisions in certain chemical practices such as extractions and separations. This report therefore practically looks at the various steps taken to concluding on the polarity of certain molecules. Prominently used in the procedure is the VPESR theory. The VPESR theory seeks to predict molecular shapes of compounds from their Lewis structure since the molecular formulas have no direct relationship to the shape of molecules. According to the VSEPR theory the molecule will take up the geometry so as to minimize valence electron repulsion in the central atom of the molecule. In addition, the presence of lone pairs and the number of valence electrons majorly influence this geometry. There are various geometries which a molecule can adopt. These include; linear, trigonal planar, tetrahedral, trigonal pyramidal and octahedral geometries. After the molecular shape has been obtained the polarity of a molecule can be predicted based on the presence of polar bonds. A bond is polar or non-polar based on the electro-negativities of the atoms in the bond. The greater the difference in electro-negativities the more polar the bond. The atom with a greater electro -negativity tends to pull the shared electrons towards themselves, hence giving them a partial negative charge and leaves the adjacent atom with a partial positive charge, thus polarity. The symbol for a dipole moment of a polar bond is -|-- > with