A boiling point is a temperature at which a substance becomes liquid and starts to evaporate. For example, ethylene glycol boils at 198 deg C while ethyl alcohol boils at 78 deg C at atmospheric pressure.
The boiling point is dependent on the molecules present in the solution. The more polar the molecules, the higher their boiling point. Examples of such molecules include acetone (CH3)2CO2 and 2-methylpropane (C3H4CO2) as well as water.
When comparing the boiling points of different molecules, a good way to look at the trends is to think about intermolecular forces. The molecules with the highest surface tension have the highest boiling points, while the molecules with the lowest surface tension have the lowest boiling points.
Several common chemicals have high boiling points, including ethyl alcohol, ethylene glycol dimethyl ether and propanol. These chemicals are used in many different applications.
For example, ethyl alcohol is used to make antifreeze. It has a boiling point of 78 deg C at atmospheric pressure, while ethylene glycol dimethyl ether has a normal boiling point of 83 deg C.
Another important molecule with a high boiling point is dichloroethylene. This molecule is the main component of antifreeze and has a boiling point of 198 deg C at atmospheric pressure.
This molecule has a relatively low surface tension because it contains four oxygen atoms. It also has a relatively high viscosity because it contains eight hydrogen atoms. This means that the molecule is very volatile at low temperatures.