Phase change problems in physics involve calculating the amount of energy required to change the state of a substance (e.g., from solid to liquid or liquid to gas) while it's at its melting or boiling point. This energy is known as latent heat. During a phase change, the temperature remains constant as the energy is used to break intermolecular bonds rather than increase the kinetic energy of the molecules. The total heat ($Q$) involved is calculated using the formula $Q = mL$, where $m$ is the mass of the substance and $L$ is the latent heat of fusion or vaporization.
To solve these problems, remember to consider both the energy required to change the temperature before the phase change and the energy required for the phase change itself. Pay close attention to units and be sure to use the correct latent heat value (fusion for melting/freezing, vaporization for boiling/condensing) for the substance in question. These problems often involve multiple steps and careful bookkeeping of energy values.
Match the term with its correct definition:
| Term | Definition |
|---|---|
| 1. Latent Heat of Fusion | A. The heat required to change a substance from liquid to gas. |
| 2. Specific Heat Capacity | B. The heat required to change a substance from solid to liquid. |
| 3. Phase Change | C. The amount of heat required to raise the temperature of 1 gram of a substance by 1 degree Celsius. |
| 4. Latent Heat of Vaporization | D. The physical process of transitioning between states of matter. |
| 5. Sublimation | E. The process where a solid changes directly into a gas. |
During a _________, the temperature of a substance remains _________ even though heat is being added or removed. The energy being added or removed is used to overcome the intermolecular forces holding the substance in its current _________. The amount of energy required is determined by multiplying the _________ of the substance by its _________ of fusion or vaporization.
Explain why the temperature of water remains constant at 100°C while it's boiling, even though heat is continuously being added.
Please log in to post your answer.
Log InEarn 2 Points for answering. If your answer is selected as the best, you'll get +20 Points! 🚀