Chemistry Reference

What's an Alkane?
An alkane is an organic compound made strictly of carbons single bonded to each other or hydrogens. No functional groups are present in an alkane.
Melting and Boiling Points
The graph above plots the melting point temperatures of the first 32 alkanes as squares. The boiling point temperatures are diamonds. Inspection of the graph shows there is a direct relationship between the number of carbons in an alkane and its melting/boiling point temperature. That is, the more carbons, the higher the temperature. For boiling point, this is a direct result of increased intermolecular (van der Waals) forces that are present in a larger molecule. The increase in van der Waals forces is a consequence of two causes. The first is the increased surface area of a large molecule, which provides greater possibility for interaction between molecules. Secondly, with a growing carbon chain, there is an increase in the number of electrons that can interact between molecules, in addition to an increased molecular mass. For melting point, the trend line does not appear as smooth as the boiling point trend line. This is due to an important difference between odd and even numbered carbon chains. Even numbered carbon chains pack tighter (closer) when solid, therefore requiring more energy to separate them and enter the liquid phase. Conversely, odd numbered carbon chains do not pack as tightly together in the solid phase and can be separated easier, thus making a lower melting point.
# Carbons (Name) Melting Point (°C) Boiling Point (°C)
1 (methane) -182.5 -161.6
2 (ethane) -181.76 -89
3 (propane) -187.7 -42.1
4 (butane) -138.4 -0.5
5 (pentane) -129.8 36.1
6 (hexane) -95 69
7 (heptane) -90.61 98.42
8 (octane) -57 125.52
9 (nonane) -53 151
10 (decane) -27.9 174.1
11 (undecane) -26 196
12 (dodecane) -9.6 216.2
13 (tridecane) -5 234
14 (tetradecane) 5.5 253
15 (pentadecane) 9.9 269
16 (hexadecane) 18 287
17 (heptadecane) 21 302
18 (octadecane) 29 317
19 (nonadecane) 33 330
20 (icosane) 36.7 342.7
21 (henicosane) 40.5 356.5
22 (docosane) 42 369
23 (tricosane) 49 380
24 (tetracosane) 52 391.3
25 (pentacosane) 54 401.9
26 (hexacosane) 56.4 412.2
27 (heptacosane) 59.5 422
28 (octacosane) 64.5 431.6
29 (nonacosane) 63.7 440.8
30 (triacontane) 65.8 449.7
31 (hentriacontane) 67.9 458
32 (dotriacontane) 69 467
Hybridization
Since all of the carbons in an alkane are single bonded to hydrogen and other carbons, all carbons are sp3 hybridized. This is true regardless of the number of branches (if any) or the number of hydrogen/carbons to which the carbon is bonded. Every carbon makes four covalent bonds, therefore sp3 is the only possibility.
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