1. Features of homologous series

The features of homologous series are follows:

(1) Successive members differ by -CH₂– unit;

(2) Members in the same homologous series have same general formula;

(3) Members in the same homologous series have similar chemical properties due to same functional group;

(4) Members show gradation in physical properties.

Some common homologous series are listed in Table 1.

Table 1: Some common homologous series (click to enlarge)

2. Name of organic compound

One example will be used to show some important features in the nomenclature of organic compounds and shown in Figure 1.

Figure 1: 2-methylpentan-3-ol shows how to name one organic compound

The name of organic compound composes three parts: prefix, stem and suffix.

Stem (orange background, “pent“) indicates the number of carbon in the longest carbon chain, and Table 3 shows several common stem.

Table 3: Stem to describe the number of carbon atoms in the longest carbon chain

One thing should be noticed is that the longest carbon chain is not always a horizontal line, and just find the longest successive carbon atoms in the molecule.

Prefix (green background, “methyl“) indicates the side chain. In DP study, there are two types of side chains: alkyl group and halogens, and shown in Table 4.

Table 4: Prefix to describe the side chain in organic compound

Suffix (blue background, “ol“) indicates the type of organic compound (homologous series). The common homologous series and their suffix are shown in Table 5.

Table 5: Suffix to describe the type of organic compounds

There is another term between stem and suffix and in yellow background.

This part is used to describe saturation of carbon-carbon bond. “an” represents C–C single bond; “en” represents C=C double bond and “yn” represents C≡C triple bond. Notice that “en” and “yn” do not represent all bonds in molecules should be double or triple bond. One double or triple bonds in one molecule can be called “en” and “yn“.

The last part in name of organic compound is number, and it indicates the position of each part in one molecule.

“2-methyl” represents CH₃ is attached on the second carbon atom, and “3-ol” represents OH is attached on the third carbon atom. The rule for numbering is the number is as smallest as possible, and when the numbers are same, functional groups have priority.

Figure 2 – 4 show more examples to describe the nomenclature of organic compounds. Figure 2 shows how to name one molecule contains two same functional group.

Figure 2: Nomenclature of but-1,3-dien-1,4-diol

Figure 4 shows how to arrange different side chains.

Figure 3: Nomenclature of 3-ethyl-2,4-dimethylpentane

Figure 4 shows some more information of numbering.

Figure 4: Nomenclature of 3-methylbutan-2-ol

One thing should be emphasized that it never uses number to indicate the position of functional group for aldehydes and carboxylic acids.

Names for ethers:

Figure 5: Nomenclature of methoxyethane

In nomenclature of ether, a short carbon chain will combine with oxygen to act as a side chain. In Figure 5, CH₃ and O are combined to be as a chain which is called methoxy, and other part in name is similar with other nomenclature. It should be noticed that, when side chain has more than one possible position, number should be used to indicate the position as well (Figure 6).

Figure 6: Nomenclature of 1-methoxypropane and 2-methoxypropane

Names for ester: Figure 7 shows the nomenclature of ester. The name of ester is more complicated, and can be deduced from the name of salt which produced from neutralization. When a base (MOH) reacts with an acid (HXO, -ic acid), one salt (MXO)  will be formed and the name of anion should be changed to -ate from -ic acid. The original acid is the first example is nitric acid, when it turns to salt, it is called nitrate. Similar to the reaction between base with carboxylic acid, such as the second example, the salt from ethanoic acid is called ethanoate.

Figure 7: Nomenclature of esters

Ester can be produced from the reaction between alcohol and carboxylic acid, and similar to neutralization reaction (third example in Figure 7). The name of ester has two parts. The first part is from alcohol, and suffix changed to -yl. The second part is from carboxylic acid, and suffix changed to -ate.

 

3. Physical properties of organic compounds

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4. Structure of benzene

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Utilising growth channels so that we be CMSable. Lead stakeholder engagement with a goal to go viral. Leveraging benchmarking to improve overall outcomes. Informing audience segments and then disrupt the balance.

Repurpose key demographics with the aim to get buy in. Execute bleeding edge with a goal to disrupt the balance. Leveraging stakeholder engagement to, consequently, improve overall outcomes. Executing below the fold so that as an end result, we make the logo bigger. Demonstrate below the fold with the possibility to innovate.