DURING THE TRANSFORMATION OF MATTER FROM THE SOLID TO THE LIQUID STATE, THE HEAT SUPPLIED DOES NOT PRODUCE A TEMPERATURE INCREASE BECAUSE

• A. the heat energy is quickly conducted away
• B. the heat capacity has become very large as the substance melts
• C. the heat gained is equal to the heat lost by the substance
• D. all the heat is used to break the bonds holding the molecules of the solid together ✓

The answer to the question is: D. all the heat is used to break the bonds holding the molecules of the solid together

During the transformation of matter from the solid to the liquid state, the heat supplied does not produce a temperature increase because all the heat is used to break the bonds holding the molecules of the solid together. When a solid is heated, its temperature rises until it reaches its melting point. At this point, the added heat energy is used to break the bonds between the molecules, allowing them to move more freely and transition into a liquid state. This process occurs at a constant temperature until all of the solid has melted, after which further heating will cause an increase in temperature.

The reason for this phenomenon lies in the nature of phase transitions. When a substance changes from one phase to another (e.g., from solid to liquid), it requires a specific amount of energy to overcome the forces holding its particles together. In the case of melting, this energy is used solely for breaking intermolecular bonds rather than increasing the kinetic energy of the particles, which would result in a rise in temperature.

This concept is known as latent heat, which refers to the heat energy absorbed or released during a phase change without a corresponding change in temperature. The heat supplied during melting is entirely consumed in breaking these intermolecular bonds, resulting in no change in temperature until all of the solid has been converted into liquid.