What Are the Physical Properties of Alkanes and Cycloalkanes

Determine whether substituents are on the same or different sides of the ring to determine cis or trans. To perform a chair- 

Following is a planar hexagon representation of one isomer of 1,2,4-trimethylcyclohexane. Draw the alternative chair conformations of this compound, and state which is the more stable. 

The most important property of alkanes and cycloalkanes is their almost complete lack of polarity. As we saw in Section 1.2C, the difference in electronegativity between carbon and hydrogen is 2.5 — 2.1 = 0.4 on the Pauling scale, and given this small difference, we classify a C—H bond as nonpolar covalent. Therefore, alkanes are nonpolar compounds, and there are only weak interactions between their molecules. 

Pentane and cyclohexane.The electron density models show no evidence of any polarity in alkanes and cycloalkanes. 

The boiling points of alkanes are lower than those of almost any other type of compound with the same molecular weight. In general, both boiling and melting points of alkanes increase with increasing molecular weight (Table 3.4). 

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