Organic compound boiling points - Essay Example

In order to figure out the order of organic compound boiling point, it is important to understand their trends. The important thing to make into consideration is that the boiling point is usually indicative of the force strength bonding its molecules together. When many molecules stick together, they will consequently need more energy to break the bonds and release the molecules as gases. Three important trends are considered including branching, which decreases the compound’s boiling point, and the number of carbons as boiling points increases with the increase in carbon atoms.

Additionally, the relative strength of intermolecular forces is important (Hill & John, 2011: p32). The strength of the bonds in descending order is; Ionic> Hydrogen bonding> dipole- dipole> Van der Waals forces of dispersion. The influence of these attractive forces is dependent on the present, functional groups. The first trend is the strength, relative for all four compounds, of the intermolecular forces. Molecules that are held together by dipole- dipole interactions, formed by the polarization of C-O bonds have a lower intermolecular energy when compared to compounds with hydroxyl groups, which are, in turn, capable of forming hydrogen bonds (Macomber, 2009: p11).

Organic alcohols have significantly higher boiling points than other organic compounds because of this property, as can be derived. Molecules that have relatively the same molecular weights have their boiling points determined by the present, functional group. 3-Methyl-2-Butanone has a dipole-dipole intermolecular interaction model, and so it has a significantly low boiling point as compared to the other organic alcohols with hydrogen intermolecular bonding (Macomber, 2009: p12). The positive end of one molecule is attracted and bonded to a negative region of another molecule.

For molecules with a similar functional group, such as the organic compounds under investigation, the boiling points increase with a rise in molecular weight. The key force that connects molecular size and intermolecular strength is the Van der Waals forces of dispersion that are proportional to the molecules’ surface area (Mehta & Manju, 2009: p29). Therefore, as the length of the chain increases, the surface area of the molecules also increases. Consequently, this results in an increased capability of the molecules in the compound to be attracted to each other.

As the length of the chain increases, regions where they line up with each other increase. Each interaction may not be worth a lot, but added up over the entire chain length, the Van der Waals forces of dispersion have the ability to exert tremendous effects (Mehta & Manju, 2009: p29). 1-Hexanol has the highest molecular weight, coming in at 102.67 g/mol1, thus provides more surface area for intermolecular interaction. With the increased energy required to separate the molecules, the boiling point is high.

Both 1-Pentanol and 3-Methyl-1-butanol have a molecular weight of 88.15 g/mol1, which is still higher than 3-methyl-2-butanone, which has a molecular weight of 86.13 g/ mol. Molecular symmetry is yet another by-product of Van der Waals forces of dispersion’s dependence on surface area. The straighter the compound’s molecules are, the better they line up, as well as bond. The spherical the molecules become, due to branching, the lower the surface area left for intermolecula