Chapter 2 - Introduction to Melting Points

Melting point

• Solid to liquid

• Range from when the first drop of liquid if observed till last bit of solid is liquefied

• Unique property of compound

• Two samples with same melting point are not necessary the same compound

• Soluble impurities lower and broaden melting point range (freezing point depression → disrupts the crystalline lattice, requiring less energy to melt)

• Insoluble impurities have no effect

• Inaccurate melting points due to poor heat transfer. Sample should be finely powdered and firmly packed into capillary tube.