Question

part 4: states of matter - long answer (6 points) 8. if you heat up a substance from a solid to a liquid to a gas, there will be two periods of time when that substance maintains a constant temperature. what are those two periods and why does the temperature hold steady during those times?

Explanation:

The two periods are during melting (solid - to - liquid) and boiling (liquid - to - gas). During melting, heat energy is used to break the intermolecular forces holding the solid together rather than increasing the kinetic energy of the molecules, so temperature remains constant. During boiling, heat energy is used to overcome the intermolecular forces to change the liquid to a gas, not to raise the temperature.

Answer:

The two periods are melting (solid - to - liquid) and boiling (liquid - to - gas). The temperature holds steady because heat energy is used to break intermolecular forces instead of increasing molecular kinetic energy.