The students of 4 PTM doing the experiment (
IUPAC: ethanamide) is an organic compound with the formula CH3CONH2. It is the simplest amide derived from acetic acid. It finds some use as a plasticizer and as an industrial solvent. The related compound
N,N-dimethylacetamide (DMA) is more widely used, but it is not prepared from acetamide. [Source:
Wikipedia]
Acetamide is a white crystalline solid with melting point in the range of 78 - 80 oC and boiling point at 221 oC. It is soluble in hot water and alcohol but slightly soluble in ether. In the U.S., the California Environmental Protection Agency added acetamide to the list of compounds known to
cause cancer or reproductive toxicity.
Melting point is the temperature at which a solid changes to a liquid under a specified pressure while
freezing point is the temperature at which a liquid of specified composition solidifies under a specified pressure. For most substances, melting and freezing points are approximately equal.
Because of the ability of some substances to supercool, the freezing point is not considered to be a characteristic property of a substance. When the "
characteristic freezing point" of a substance is determined, in fact the actual methodology is almost always "the principle of observing the disappearance rather than the formation of ice", that is, the
melting point.
When solid is heated, the particles gain kinetic energy and vibrate more vigorously. Particles vibrate faster until they gain enough energy to overcome the forces that hold them at their fixed position. At this stage they will reach the melting point and turns to liquid.
When liquid is heated, particles move faster and faster as the temperature increase. Particles at the surface will gain enough energy to escape as a gas. We will be referring the temperature at this stage as the boiling point.
As the liquid freezes, the particles lost some energy and move slower. Stronger bonds will be formed during this process. The energy released is the same as the energy lost to the surrounding. The temperature remain unchanged at this stage and it will be referred as the freezing point. The experiment done on this topic can be reviewed here:
Amali Kimia: Determination of Melting and Freezing Points of AcetamideREMARKS: Napthalene??
