An investigation to find out the effect of carbon chains on the boiling point of an alcohol

Authors Avatar

An investigation to find out the effect of carbon chains on the boiling point of an alcohol

AIM:

         To find out how the boiling point changes with the different amount of carbon bonds and the length of the carbon chain. To use 2 different methods and compare them, and see which method helps. Then to see which alcohols are affected the most.

Scientific Knowledge:

                        Molecules exist as distinct, separate collections of matter. The bonds within a molecule are typically quite strong, such that it's usually necessary to heat a molecule to very high energies before the bonds begin to break. For example, water is stable to decomposition to hydrogen and oxygen up to temperatures well above 500 C. In contrast, the forces between molecules tend to be relatively weak. If we chose an arbitrary scale in which the bonds between atoms within a molecule are set at 100, then the forces between molecules range between 0.001 and 15. In other words, it generally takes far less energy to separate molecules from one another than it does to take molecules apart. The forces between molecules are called intermolecular forces. The stronger the attractions between particles (molecules or ions), the more difficult it will be to separate the particles.

When substances melt, the particles are still close to one another but the forces of attraction that held the particles rigidly together in the solid state have been sufficiently overcome to allow the particles to move. When substances boil, the particles are completely separated from one another and the attractions between molecules are completely overcome. The energy required to cause substances to melt and to boil, and thus disrupt the forces of attraction, comes from the environment surrounding the material. If you place a piece of ice in your hand, the ice will melt more quickly than if it is placed on a cold counter top. The energy required to melt the ice comes from your hand, your hand gets colder and the ice gets warmer. Isomers are molecules that have the same molecular formula, but have a different arrangement of the atoms in space.

Join now!

There are two types of organic compounds used in this experiment: alkanes and alcohols. Alkanes contain only carbon and hydrogen atoms and all C-C and C-H bonds are single bonds (intermolecular forces). The two alkanes used in this experiment are n-pentane and hexane. (The letter "n" means that all the carbon atoms are attached in a chain. n- Pentane is called "normal" pentane.) Alcohols contain the -OH functional group in addition to carbon and hydrogen atoms. That excludes any different arrangements, which are simply due to the molecule rotating as a whole, or rotating about particular bonds. Where the atoms ...

This is a preview of the whole essay