Although the term "melting point" is used to describe a solid/ liquid change, we generally list melting ranges rather than single melting point. For most pure substances, the range is narrow (about 1-3 C) and is indicative of a substances purity. The two lab groups observed the melting ranges of vanillin obtained though a chemical reaction. From the following data, whose vanillin is more pure? Group A or Group B? Explain.
Groups Observed Melting point range (C)
Pure Vanillin 81-83 C
Group A 79-81 C
Group B 80-86 C