How is the melting point of a compound determined in the lab?

How is the melting point of a compound determined in the lab?

• A. By dissolving it in water
• B. By heating a small sample and observing the temperature at which it melts
• C. Using infrared spectroscopy
• D. By comparing it to standard melting points

Answer: (B)

The melting point of a compound is determined by heating a small sample and observing the temperature at which it transitions from solid to liquid. This process involves the application of controlled heat to the sample while monitoring the temperature closely with a thermometer. When the substance begins to melt, it will maintain a constant temperature until fully liquefied, as the heat energy is used to overcome the intermolecular forces holding the solid together rather than increasing the temperature. This technique allows for precise measurement of the melting point, which is an important characteristic used to identify compounds and assess their purity. A pure substance typically has a sharp melting point range, while impurities can cause depression of the melting point and broadening of the range. Other methods mentioned, such as dissolving the compound in water or using infrared spectroscopy, do not directly measure the melting point. Comparing to standard melting points is a useful technique for identifying compounds but relies on having prior knowledge of the expected melting point to be effective, rather than directly determining it through experimental observation.

The melting point of a compound is determined by heating a small sample and observing the temperature at which it transitions from solid to liquid. This process involves the application of controlled heat to the sample while monitoring the temperature closely with a thermometer. When the substance begins to melt, it will maintain a constant temperature until fully liquefied, as the heat energy is used to overcome the intermolecular forces holding the solid together rather than increasing the temperature.

This technique allows for precise measurement of the melting point, which is an important characteristic used to identify compounds and assess their purity. A pure substance typically has a sharp melting point range, while impurities can cause depression of the melting point and broadening of the range.

Other methods mentioned, such as dissolving the compound in water or using infrared spectroscopy, do not directly measure the melting point. Comparing to standard melting points is a useful technique for identifying compounds but relies on having prior knowledge of the expected melting point to be effective, rather than directly determining it through experimental observation.