Questions: 1. A student performs two melting point determinations on a crystalline product. In one determination, the capillary tube contains a sample about 1-2 mm in height and the melting point range is found to be 141-142C. In the other determination, the sample height is 4-5 mm and the melting point range is found to be 141-145C. Explain the broader melting point range observed for the second sample. The reported melting point for the compound is 143C. 2. A white crystalline compound melts at 111-112C and the melting point capillary is set aside to cool. Repeating the melting point analysis, using the same capillary, reveals a much higher melting point of 140C. Yet repeated recrystallization of the original sample yields sharp melting points no higher than 114C. Explain the behavior of the sample that was cooled and then remelted. 4. When taking a boiling point of a compound, why is the micro boiling point determined at the point when the last bubble has left the bottom of the bell and the liquid begins to rise in the bell