Hexane is non polar It has van der waal forces It has london dispersion forces How do these factors influence the bonding in hexance? ........................................................................................ ... so is methane However hexane has a higher boiling point than methane, but why? Hexane has a boiling point of 68.7 degrees and methane has a boiling point of -162 degrees. WHY is this, like it is??
Their difference lies in their size. A common definition of a liquid is "something" wherein the molecules have an interaction with each other but not strong enough to keep it's shape. A liquid doesn't "expand" per se. A gas is "something" wherein the interaction between molecules is minimal. A gas doesn't keep its shape and it expands (because nothing is there to hold two gas molecules together). A standing liquid generates a gaseous "vapor" in its headspace. This vapor has a certain pressure, called the vapor pressure. For example, water at room temperature, has a vapor pressure of 20 Torrs (Our atmosphere's pressure is 760 Torrs). When you increase the temperature of water to, say, 90 degrees C, the vapor pressure increase to 517 Torr. When you increase the temperature further to say 100 degrees C (boiling point), the vapor pressure of water matches the pressure of the atmosphere. At this point, the water vapor begins to "push" at the atmosphere and you get boiling. I don't know all the factors governing the boiling of liquids. There are many --- for example, adding salt to water can change its boiling point drastically. One of the key factors that affect boiling point, however, is strength of interaction. Hexane and methane are both non-polar. However, hexane is larger (6 carbon) compared to methane (1 carbon). What this means is that at any given time, there are more van der Waals interactions between any two hexane molecules than between any two methane molecules. The number of interactions can then affect how much hexane or methane vapor is there and consequently, by how much you you have to increase the temperature to before you can have a pressurized enough vapor to "push" at the atmosphere (i.e. boil).
