Hydrocarbons structural diagrams/model

Fig. 4. Structural diagrams for C2 hydrocarbon ligands on metal clusters that are available as model compounds for chemisorbed surface species, numbered in accordance with the entries in Table IV (M = metal atom).

The simplest aromatic hydrocarbon is benzene, CgHg. Chemists have struggled for decades to find a structural diagram for benzene that is consistent with its physical and chemical properties, but without success. Common forms and its space-filling model are... 

The ideas underlying elemental structures models are to establish microstructures experimentally, to compute free energies and chemical potentials from models based on these structures, and to use the chemical potentials to construct phase diagrams. Jonsson and Wennerstrom have used this approach to predict the phase diagrams of water, hydrocarbon, and ionic surfactant mixtures [18]. In their model, they assume the surfactant resides in sheetlike structures with heads on one side and tails on the other side of the sheet. They consider five structures spheres, inverted (reversed) spheres, cylinders, inverted cylinders, and layers (lamellar). These structures are indicated in Fig. 12. Nonpolar regions (tails and oil) are cross-hatched. For these elemental structures, Jonsson and Wennerstrom include in the free energy contributions from the electrical double layer on the water... 

There are three different structures for the hydrocarbon pentane, C5H12. These structures are called geometric isomers because each has a different shape. Draw electron dot diagrams for the three possibilities. You can substitute a dash, like the stick in the gmndrop models, to represent each pair of electrons. 

The formulas of formic acid, H—COOH, acetic acid, CHj—COOH, and propanoic acid, CH3CH2—COOH, suggest the structure of the first three members of a series of carboxylic acids, which contain the carboxyl group, —COOH. Their Lewis diagrams and ball-and-stick models are shown in Figure 13.19. As with hydrocarbons, alcohols, and ethers, the carbon chain may extend indefinitely. 

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