Energy of Phase Changes · 相变能量
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| heat of fusion/hiːt ɒv ˈfjuːʒn/ | 熔化热 | róng huà rè |
| heat of vaporization/hiːt ɒv ˌveɪpəraɪˈzeɪʃn/ | 汽化热 | qì huà rè |
The flat spots on the graph
- Heat ice steadily and its temperature climbs -- then stalls at $0$ degrees.
- All the heat goes into melting, not warming.
- Only once it is fully liquid does the temperature rise again.
- Those flat spots hide a big energy cost.
图上的平坦段
- 稳定地加热冰,它的温度上升——然后在 $0$ 度停住。
- 所有的热都用于融化,而不是升温。
- 只有等它完全变成液体,温度才再次上升。
- 那些平坦段藏着巨大的能量代价。
Temperature pauses
- During a phase change, the temperature stays constant.
- Added heat breaks the attractions rather than speeding particles up.
- So a heating curve has flat plateaus.
温度停顿
- 在相变过程中,温度保持不变。
- 加入的热用于断开吸引,而不是让粒子加速。
- 所以加热曲线有平坦的平台。
The temperature stays constant during a phase change. · 在相变期间温度保持恒定。
Heat breaks attractions instead of raising the temperature. · 热量用于破坏吸引力，而不是提高温度。
On a heating curve, a phase change appears as a flat . · 在加热曲线上，相变表现为一段平坦的。
The temperature is constant, giving a flat plateau. · 温度恒定，形成平坦的平台。
The hidden heats
- The heat of fusion 熔化热 is the energy to melt a solid.
- The heat of vaporization 汽化热 is the energy to boil a liquid.
- Vaporization takes far more energy than fusion.
隐藏的热
- 熔化热是把固体融化所需的能量。
- 汽化热是把液体煮沸所需的能量。
- 汽化所需的能量远多于熔化。
For water, which usually requires more energy? · 对于水，通常哪种情况需要更多能量？
The heat of vaporization is much larger than the heat of fusion. · 汽化热远大于熔化热。
Warming versus changing
- Warming within one phase uses $q = mc\Delta T$.
- Changing phase uses $q = m \times$ (heat of fusion or vaporization).
- A full heating curve combines both.
升温对比相变
- 在同一相内升温用 $q = mc\Delta T$。
- 相变用 $q = m \times$(熔化热或汽化热)。
- 一条完整的加热曲线把两者结合起来。
The heating curve · 加热曲线
Temperature stays flat while a substance melts or boils, as latent heat breaks the forces between particles. · 在物质熔化或沸腾时，温度保持不变，因为潜热用于破坏粒子间的作用力。
To warm a liquid without changing its phase, you use... · 在不改变相的情况下加热液体，应使用...
Within a single phase, use $q = mc\Delta T$. · 在同一相内，使用$q = mc\Delta T$。
Why does steam burn worse than boiling water at the same temperature?
- Steam releases its large heat of vaporization as it condenses on skin.
- That extra energy makes the burn much worse.
为什么同样温度下蒸汽比沸水烫伤更严重?
- 蒸汽在皮肤上冷凝时释放它巨大的汽化热。
- 那份额外的能量使烫伤严重得多。
Steam burns worse than boiling water because it also releases its... · 蒸汽烫伤比沸水严重，因为它还释放了...
Condensing steam gives up a large heat of vaporization to the skin. · 冷凝蒸汽向皮肤释放大量的汽化热。
You should use $q = mc\Delta T$ during a phase change. · 在相变期间你应该使用$q = mc\Delta T$。
With $\Delta T = 0$, use the latent heat instead. · 使用$\Delta T = 0$时，应使用潜热。
The temperature is constant during a phase change -- the heat goes into breaking attractions, so do not use $q = mc\Delta T$ there ($\Delta T = 0$). Use the latent heat instead. Vaporization needs much more energy than fusion. And the plateaus on a heating curve mark the phase changes.
相变过程中温度不变——热用于断开吸引,所以那里不能用 $q = mc\Delta T$($\Delta T = 0$)。要改用潜热。汽化所需能量远多于熔化。而且加热曲线上的平台标记着相变。
During a phase change the temperature holds constant while heat breaks attractions -- the plateaus on a heating curve. The heat of fusion melts a solid and the heat of vaporization boils a liquid (much larger). Warming within a phase uses $q = mc\Delta T$; changing phase uses the latent heat.
相变过程中温度保持不变,而热用于断开吸引——即加热曲线上的平台。熔化热融化固体,汽化热煮沸液体(大得多)。相内升温用 $q = mc\Delta T$;相变用潜热。