PROPERTIES OF ALKANES

=Saturation= Alkanes are said to be "saturated" and this means that there are the maximum number of hydrogen atoms attached to each carbon. There are no double bonds. This makes them better fuels, as they release more energy in a combustion reaction. =Polarity= Alkanes are non-polar. The C-H bond is weakly polar, due to difference in electronegativity between C and H atoms, however due to the symmetry of C-H bonds around the whole alkane, any dipoles are even in size and balance or cancel out. This means that alkanes do not mix with water. =Melting and Boiling Point= Alkanes have low melting or boiling points because of the very weak intermolecular forces between alkane molecules. Methane, ethane, propane, and butane are gases at room temperature. As the carbon chain gets longer, there are more electrons in a molecule. This means that there are more (relatively) stronger intermolecular forces between the molecules. As a result, it takes more energy to break these forces, and thus the melting or boiling points increase. [image:http://upload.wikimedia.org/wikipedia/commons/thumb/8/82/AlkaneBoilingMeltingPoint.png/400px-AlkaneBoilingMeltingPoint.png] =Viscosity= [image:http://img2.wikia.nocookie.net/__cb20091219200921/recipes/images/e/e0/Olive-Oil.jpg] As the carbon chain increases in length, there are more intermolecular forces holding molecules together. This means that the substance will become denser as the carbon chain increases. Oils are very viscous, and can have carbon chains of over 25 carbons!