Melting Point

Source: Vy M. Dong and Jan Riedel, Department of Chemistry, University of California, Irvine, CA

One of the most important properties of a crystalline solid is its melting point. It can be used to determine the purity of a known compound and gives important information about the stability of the formed crystals.

1. Sample Preparation

1. Take a special glass capillary that fits the melting point apparatus in use.
2. Dip the open end of the capillary into a sample of benzoic acid
3. Gently tap the glass capillary on a hard surface, like a table, so that the benzoic acid moves down to the very bottom of the glass capillary

2. Measuring the Melting Point

1. Insert the glass capillary into the melting point apparatus.
2. Heat the apparatus with a rate of 10
   

A sample of pure benzoic acid will melt at 122 °C.

The melting point is an important property of a crystalline solid. It can be measured easily and gives information about the identity and purity, as well as the bonding strength within the crystal lattice.

Due to its simple determination, the melting point is still an important property that is commonly employed to identify compounds and qualify their purity. The melting point can not only be used to identify solids, but also liquids like isopropanol. Through derivatization of isopropanol wit