Formulas condensed

By analogy with the Helmholtz condenser formula, for small potentials the diffuse double layer can be likened to an electrical condenser of plate distance /k. For larger yo values, however, a increases more than linearly with o, and the capacity of the double layer also begins to increase. 

IHP) (the Helmholtz condenser formula is used in connection with it), located at the surface of the layer of Stem adsorbed ions, and an outer Helmholtz plane (OHP), located on the plane of centers of the next layer of ions marking the beginning of the diffuse layer. These planes, marked IHP and OHP in Fig. V-3 are merely planes of average electrical property the actual local potentials, if they could be measured, must vary wildly between locations where there is an adsorbed ion and places where only water resides on the surface. For liquid surfaces, discussed in Section V-7C, the interface will not be smooth due to thermal waves (Section IV-3). Sweeney and co-workers applied gradient theory (see Chapter III) to model the electric double layer and interfacial tension of a hydrocarbon-aqueous electrolyte interface [27]. 

Representation of Chemical Compounds 21 Structure diagram Condensed formula... 

Much of the communication between insects involves chemical messengers called pheromones A species of cockroach secretes a substance from its mandibular glands that alerts other cockroaches to its presence and causes them to congregate One of the principal components of this aggregation pheromone is the alkane shown in the bond line formula that follows Give the molecular formula of this substance and represent it by a condensed formula... 

Given the following condensed formulas, write the molecular formulas for the following molecules. 

In organic chemistry, structural formulae are frequently presented as condensed formulae. This abbreviated presentation is especially useful for large molecules. Another way of presenting structural formulae is by using bonds only, with the understanding that carbon and hydrogen atoms are never explicitly shown. 

Carbons on the end of a chain are bonded to only one other carbon, so they have three additional bonds that are filled by hydrogen and are labeled as CHj in a condensed formula. 

Molecular formulas merely include the kinds of atoms and the number of each in a molecule (as C4H , for butane). Structural formulas show the arrangement of atoms in a molecule (see Fig. 1-1). When unshared electrons are included, the latter are called Lewis (electron-dot) structures [see Fig. 1-1(/)]. Covalences of the common elements—the numbers of covalent bonds they usually form—are given in Table 1-1 these help us to write Lewis structures. Multicovalent elements such as C, O. and N may have multiple bonds, as shown in Table 1-2. In condensed structural formulas all H s and branched groups are written immediately after the C atom to which they are attached. Thus the condensed formula for isobutane [Fig. l-l(f>)) is CH,CH(CH,)... 

Problem 1.5 Write structural and condensed formulas for (a) three isomers with molecular formula C,H, and (b) two isomers with molecular formula C,H. ... 

Probimn 14.40 Write the condensed formulas for the two isomeric thioethers giving methane and propane on hydrogenolysis. <... 

Sometimes condensed formulas are used in which the bonds are not shown. 

To save space and time in the representation of organic structures, it is common practice to use condensed formulas in which the bonds are not shown explicitly. In using condensed formulas, normal atomic valences are understood throughout. Examples of condensed formulas are... 

Write an expanded structural formula with a line for each bond (like the formulas on p. 32) for each of the following substances which are represented by a condensed formula ... 

Exercise 12-1 Write expanded structures showing the C-C bonds for each of the following condensed formulas. Name each substance by the IUPAC system, a. (CH2)10 d. the position and configurational... 

Convert each of the following models into a condensed formula ... 

The alcohols (alkanols) form another homologous series with the general formula C H2 +1OH (or R— OH, where R represents an alkyl group). All the alcohols possess an -OH as the functional group. Table 15.2 shows the names and condensed formulae of the first four members along with their melting and boiling points. 

Hie condensed formula does not show bonds. Central atoms are usually followed by the atoms that bond to them even though this is not the bonding order. For instance, the three hydrogens following the carbon in CHjiNThU do not bond to the nitrogen. 

An unbranched alkane (n-alkane) of 28 carbons has 26 methylene (CH2) groups flanked by a methyl (CH3) group at each end. The condensed formula is CH3(CH2)26CH3. 

Find the condensed formula of linolenic acid in Table 15.1 and use example 15.1 as a guide. 

The final, and most common method of writing structures and formulas involves condensed formula notation . Condensed formula notation simply excludes the lines. To save time and space, many chemists use condensed formula notation. In this book, many of the reagents and solvents will be written in condensed formula notation. The following illustration gives a few examples of condensed formula notation. 

Condensed formulas are often confusing, especially when they involve carbonyl groups. Whenever you see a complicated condensed formula, convert it to a Lewis structure first for clarity. 

Do not use condensed or line-angle formulas for reaction sites. Draw all the bonds and all the substituents of each carbon atom affected throughout the mechanism. Three-bonded carbon atoms in intermediates are most likely to be radicals in the free-radical reactions we have studied. If you draw condensed formulas or line-angle formulas, you will likely misplace a hydrogen atom and show a reactive species on the wrong carbon. 

Three-bonded carbon atoms are most likely reactive intermediates carbocations in reactions involving strong electrophiles, carbanions in reactions involving strong nucleophiles, and free radicals in radical reactions. If you draw condensed formulas... 

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