The reason to seal the capillary tube from the open end for the melting point determination for a compound that sublimes should be stated. Concept introduction: For a crystalline substance, the temperature at which the substance changes from solid phase to liquid phase is referred to as melting point. Melting point is directly associated with the presence of intermolecular forces like hydrogen bonding, dipole-dipole interactions. High molecular symmetry, large surface area, polarity is related to high melting temperature. A pure compound melt at a narrow range and compounds with impurities have broad melting temperature. Melting points are obtained by filling the organic compound into the capillary tube with one sealed end. Sublimation is a process where a gaseous phase is obtained directly from the solid phase.

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Chapter 14, Problem 4Q

Interpretation Introduction

Interpretation:

The reason to seal the capillary tube from the open end for the melting point determination for a compound that sublimes should be stated.

Concept introduction:

For a crystalline substance, the temperature at which the substance changes from solid phase to liquid phase is referred to as melting point. Melting point is directly associated with the presence of intermolecular forces like hydrogen bonding, dipole-dipole interactions. High molecular symmetry, large surface area, polarity is related to high melting temperature.

A pure compound melt at a narrow range and compounds with impurities have broad melting temperature. Melting points are obtained by filling the organic compound into the capillary tube with one sealed end.

Sublimation is a process where a gaseous phase is obtained directly from the solid phase.

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