How does the number of bonds in a carbon chain affect its melting and boiling points?
given the same number of bonds?
the double bonds, and triple bonds are very easily broken, as compared to the C-H bonds.
http://www.engineeringtoolbox.com/fuels-boiling-point-d_936.html
compare pentane, and pentene, butane, and butylene.
The length of a carbon chain has more to do with melting and boiling points than the number of bonds. Double bonds tend to lower the melting point if the chain is in a "cis-" configuration. As BobPursley pointed out, the question is not clear enough for a definite answer.
The number of bonds in a carbon chain has a significant effect on the melting and boiling points of the compound. As the length of the carbon chain increases, the melting and boiling points generally increase as well.
To understand why, let's consider the intermolecular forces involved. In a carbon chain, the primary intermolecular force at play is Van der Waals forces, specifically London dispersion forces. These forces are caused by temporary fluctuations in electron distribution, leading to temporary partial charges.
When the carbon chain is short, the surface area available for these temporary partial charges to interact is relatively small. As a result, the London dispersion forces are weaker, and the melting and boiling points are lower.
However, as the carbon chain lengthens, the surface area for interaction increases. The increased surface area allows for more extensive temporary partial charges and a stronger London dispersion force. Consequently, the melting and boiling points of the compound increase.
It is important to note that other factors such as branching, functional groups, and other intermolecular forces like hydrogen bonding or dipole-dipole interactions can also influence the melting and boiling points of carbon chains. However, the primary trend observed is that longer carbon chains generally have higher melting and boiling points due to the increased strength of London dispersion forces.