Melting Point Discussion I am fairly sure the unknown compound is lauric acid because it had the melting point closest to that of our observations, but I cannot be completely sure because 2-nitrobenzaldehyde’s melting point was also very close to our observations. One way I would be able to tell for sure if it was lauric acid would be to add lauric acid to my unknown, and if the melting point stayed the same I would know my unknown was definitely lauric acid, and if the melting point went down I would know my unknown was some other compound (Padias 2015). If I found the compound was not lauric acid, I would do the same procedure with 2-nitrobenzaldehyde. The appearance of the solid was a white and crystalline, which is consistent with lauric acid, so that helps to confirm my identification. …show more content…
This effect is known as melting-point depression, and it is a colligative property because it depends on the concentration particles rather than their individual properties (Padias 2015). The compounds looked at in lab are crystalline solids, so they are arranged tightly in a particular lattice as a solid, and for the compound to melt those intermolecular forces holding the lattice together must be broken. However, when a foreign substance is introduced, the lattice is disrupted, meaning that the lattice is already being broken down before heat is added. Therefore, it takes less energy for the intermolecular forces to be broken to transition for a solid to a liquid, and the melting point occurs at a lower temperature. The more impure molecules there are, the more the lattice is disrupted, and the less energy it takes to melt (Brown et al.,