Electrostatic potential maps water molecule

Electrostatic potential map for hydronium+3 water molecules shows most positively-charged regions (in blue) and less positively-charged regions (in red). 

Examine electrostatic potential maps for free hydronium and for hydronium complexed to three and nine water molecules hydronium+3 water and hydronium+9 water, respectively). What happens to the positive charge as more and more water molecules are involved Rationalize your result. 

Experimental reactivity patterns are based on solution behavior which are influenced by interactions between solvent and reacting molecules (especially ions). Compare electrostatic potential maps of 2-methyl-2-propyl cation and dimethylhydroxy cation. Identify sites that might form strong hydrogen bonds with water. Which ion will be better stabilized by its interaction with water ... 

Compare and contrast the electrostatic potential map of a typical detergent with that of a typical soap (stearate). Which part of each molecule will be most water soluble (hydrophilic) Draw a Lewis structure that describes each molecule s water-soluble group (make sure you indicate all necessary formal charges and lone pairs). Which part(s) of each molecule will be most grease soluble (lipophilic) What kinds of atoms and bonds are found in these groups ... 

The previous calculation assumed that the solvation energy of ammonium was equal the solvation energy of a single water molecule times the number of water binding sites. Is this a valid assumption Compare the electrostatic potential maps of ammonium ion and ammonium ion+water. For which are the exposed hydrogens more acidic Did the calculation underestimate or overestimate the difference in solvation energies ... 

Fig. 1.1 An electrostatic potential map of a water molecule [Scanned from Silberberg (2006, 4th edition)]...

Aggregation of soap in micelles. The electrostatic potential map of a soap molecule shows high electron density in the negatively charged head and medium electron density (green) in the hydrocarbon tail. In water, soap forms a cloudy solution of micelles, with the hydrophilic heads in contact with water and the hydrophobic tails clustered in the interior. The Na+ ions (not shown) are dissolved in the water surrounding the micelle. 

The ability of water molecules to accept and donate protons is the basis of acid-base reactions in aqueous solution. The electrostatic potential map shows the transfer of a proton between two water molecules to form a hydronium ion and a hydroxide ion. 

Electrostatic potential map of the hydronium ion. The proton is always associated with water molecules in aqueous solution. The ion is the simplest formula of a hydrated proton. 

The electrostatic potential map shows an electron rich region at the oxygen end of the molecule. Consequently, water is a polar molecule. Table 10.2 summarizes common geometries and molecular polarity. 

H2O. Water molecules are polar. They have bond dipoles because of the electronegativity difference between H and O, and the bond dipoles combine to produce a resultant dipole moment of 1.84 D. The electrostatic potential map for water provides visual evidence of a net dipole moment on the water molecule. The molecule cannot be linear, for this would lead to a cancellation of bond dipoles, just as with CO2. We have predicted with the VSEPR theory that the H2O molecule is bent, and the observation that it is a polar molecule simply confirms the prediction. 

Whereas Eq.(5.58) serves for the determination of local interactions between cluster models of a zeolite and interacting molecules, analytical expressions are needed for the interaction potential if one wishes to compute vibrational frequencies for purpose of comparison with experiment or if the potentials are to be used in Monte Carlo or molecular-dynamics simulation calculations. Sauer and co-workers developed such analytical potentials for the water-silica interaction system. The method makes use of the molecular electrostatic potential (MEP) maps and the functional form of EPEN/2 (Empirical Potential based on interactions of Electrons and Nuclei). EPEN/2 potential functions consist of a point-charge interaction term and... 

Figure 9.4 presents the electrostatic potential (EP) maps for F3CCI and H2O molecules. One can see that in a case of chlorine center there is the region of the positive electrostatic potential in the elongation of the C-Cl bond (o-hole) and the belt of the negative EP around this atom being the consequence of the existence of the lone electron pairs. In a case of water molecule the whole hemispheres of H-atoms are characterized by the positive EP. 

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