Deviation from the Ideal Gas Law · 偏离理想气体定律
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| real gas/rɪəl ɡæs/ | 真实气体 | zhēn shí qì tǐ |
Where the perfect model breaks
- The simple gas equation works beautifully -- most of the time.
- But squeeze a gas hard or chill it, and it misbehaves.
- Real particles take up space and do attract each other.
- Knowing when the model fails is as useful as the model itself.
完美模型在哪里失效
- 简单的气体方程运作得很漂亮——大多数时候。
- 但把气体使劲挤压或冷却,它就会失常。
- 真实的粒子占据空间,也确实相互吸引。
- 知道模型何时失效,与模型本身一样有用。
Two broken assumptions
- The ideal model assumes zero particle volume and no attractions.
- At high pressure, the particles' own volume starts to matter.
- At low temperature, their attractions pull them together.
两个被打破的假设
- 理想模型假设粒子体积为零、无吸引。
- 在高压下,粒子自身的体积开始变得重要。
- 在低温下,它们的吸引把彼此拉到一起。
Select both · 两者 reasons real gases deviate from the ideal law. · 选择真实气体偏离理想定律的两个原因。
Finite molecular volume and intermolecular attractions cause the deviations. · 有限的分子体积和分子间吸引力导致了偏离。
High pressure, low temperature
- A real gas 真实气体 deviates most at high pressure and low temperature.
- There the particles are crowded and slow.
- At low pressure and high temperature, gases act nearly ideal.
高压、低温
- 真实气体在高压和低温时偏离最大。
- 在那里粒子既拥挤又缓慢。
- 在低压和高温下,气体表现得几乎理想。
Real gases deviate most from ideal behaviour at... · 真实气体在...时偏离理想行为最显著。
Crowded (high P) and slow (low T) is where volume and attractions matter. · 拥挤（高压）和缓慢（低温）是体积和吸引力变得重要的地方。
At low pressure and high temperature, gases behave nearly ideally. · 在低压和高温下，气体表现得几乎符合理想气体行为。
Spread out and fast-moving, molecules barely feel volume or attractions. · 分散且快速运动的分子几乎感觉不到体积或吸引力。
Which gases stray most
- Big molecules, with more volume, deviate more.
- Polar molecules, with stronger attractions, deviate more.
- Small, nonpolar gases like helium stay closest to ideal.
哪些气体偏离最大
- 大分子体积更大,偏离更多。
- 极性分子吸引更强,偏离更多。
- 像氦这样小的非极性气体最接近理想。
Which gas behaves most ideally? · 哪种气体表现得最理想？
Small, nonpolar helium has tiny volume and weak attractions. · 小且非极性的氦气具有微小体积和微弱吸引力。
Polar molecules deviate more from ideal behaviour than nonpolar ones. · 极性分子比非极性分子偏离理想行为更多。
Stronger attractions between polar molecules increase the deviation. · 极性分子间较强的吸引力增加了偏离程度。
Why does a real gas push with less pressure than $PV = nRT$ predicts at high pressure?
- Attractions pull the molecules inward, softening their wall collisions.
- So the measured pressure is a little lower than ideal.
为什么在高压下真实气体施加的压强比 $PV = nRT$ 预测的小?
- 吸引把分子向内拉,减弱了它们对器壁的碰撞。
- 所以测得的压强比理想值略低。
When gases stop being ideal · 当气体不再符合理想行为时
Sort each condition by whether a real gas behaves nearly ideally or deviates. · 根据真实气体接近理想行为还是偏离来分类每种条件。
Attractions between real molecules make the measured pressure... · 真实分子间的吸引力使得测量压力...
Inward pulls soften wall collisions, lowering the pressure. · 向内拉力减弱了壁面碰撞，降低了压力。
A real gas deviates most exactly where it is crowded (high $P$) and slow (low $T$) -- the opposite of ideal conditions. Two corrections matter: the finite volume of molecules and the attractions between them. And small, light, nonpolar gases behave most ideally.
真实气体恰好在拥挤(高 $P$)和缓慢(低 $T$)处偏离最大——与理想条件相反。有两个修正很重要:分子的有限体积和它们之间的吸引。而且小、轻、非极性的气体表现得最理想。
A real gas deviates from $PV = nRT$ because its molecules take up space and attract each other. Deviations are largest at high pressure and low temperature, and worst for big or polar molecules. At low pressure and high temperature, or for small nonpolar gases, the ideal law works well.
真实气体偏离 $PV = nRT$,因为它的分子占据空间并相互吸引。偏离在高压和低温时最大,对大分子或极性分子最严重。在低压高温下,或对小的非极性气体,理想定律运作得很好。