When it comes to physical properties, such as melting and boiling points, the values for alkanes are very low, at least for the majority of the alkanes, for example, melting point will be ranging from -182°C to -30°C (methane to decane), and boiling point will be ranging from -164°C to 174°C (again methane to decane), and with these values we can see that the bonding among alkanes is not very strong, since I don't need too much energy in order to break these bonding, but when it comes to larger molecules, such as, pentane, hexane and so on, we will see the values increasing a lot, this is due the size of the compound. In smaller compounds, with a weak bonding, I don't need to much energy in order to break these bondings, therefore to melt or boil this compound, but if I have a large molecule, even with a weak bond, it will require a lot more of energy in order to finally break the large compound.