Intermolecular and Interparticle Forces · 分子间作用力与粒子间作用力
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| London dispersion forces/ˈlʌndn dɪˈspɜːʃn ˈfɔːsɪz/ | 伦敦色散力 | lún dūn sè sàn lì |
| dipole-dipole forces/ˈdaɪpəʊl ˈdaɪpəʊl ˈfɔːsɪz/ | 偶极-偶极作用 | ǒu jí - ǒu jí zuò yòng |
| hydrogen bonding/ˈhaɪdrədʒn ˈbɒndɪŋ/ | 氢键 | qīng jiàn |
The weak grip between molecules
- Water is a liquid at room temperature, but similar-sized gases are not.
- Something makes molecules stick lightly to their neighbours.
- These attractions are far weaker than the bonds inside a molecule.
- Yet they decide whether a substance is a gas, liquid, or solid.
分子之间微弱的抓握
- 水在室温下是液体,但大小相近的气体却不是。
- 有某种东西让分子轻轻依附在邻居身上。
- 这些吸引比分子内部的键弱得多。
- 可它们却决定一种物质是气体、液体还是固体。
London dispersion forces
- Every molecule has London dispersion forces 伦敦色散力.
- Fleeting uneven electron clouds create tiny, temporary attractions.
- Bigger molecules, with more electrons, have stronger dispersion.
伦敦色散力
- 每个分子都有伦敦色散力。
- 瞬息万变的不均匀电子云产生微小的、短暂的吸引。
- 更大的分子电子更多,色散更强。
All molecules experience London dispersion forces. · 所有分子都经历伦敦色散力。
Temporary uneven electron clouds occur in every molecule. · 瞬态不均匀电子云出现在每个分子中。
Larger molecules with more electrons have stronger dispersion forces. · 具有更多电子的较大分子具有更强的色散力。
More electrons make bigger temporary dipoles, so stronger dispersion. · 更多电子产生更大的瞬态偶极，因此色散力更强。
Dipole-dipole forces
- Polar molecules also feel dipole-dipole forces 偶极-偶极作用.
- The positive end of one molecule attracts the negative end of another.
- These are stronger than dispersion alone.
偶极-偶极作用
- 极性分子还感受到偶极-偶极作用。
- 一个分子的正端吸引另一个分子的负端。
- 它们比单独的色散更强。
Hydrogen bonding
- The strongest of these is hydrogen bonding 氢键.
- It happens when hydrogen is bonded to N, O, or F.
- It gives water its unusually high boiling point.
氢键
- 其中最强的是氢键。
- 它发生在氢与 N、O 或 F 成键时。
- 它赋予水异常高的沸点。
Which intermolecular force? · 哪种分子间作用力？
Identify the strongest force acting between each pair of molecules. · 识别每对分子之间作用的最强作用力。
Which is the strongest intermolecular force? · 哪种是分子间作用力中最强的？
Hydrogen bonding (H to N, O, or F) is the strongest of the three. · 氢键（H连接N、O或F）是这三种作用力中最强的。
Hydrogen bonding requires hydrogen bonded to... · 氢键要求氢原子连接在...
Only the small, very electronegative N, O, F give true hydrogen bonds. · 只有体积很小且电负性很强的N、O、F才能形成真正的氢键。
Select all · 所有 forces a polar molecule like $\text{HCl}$ experiences. · 选择极性分子如$\text{HCl}$所经历的所有作用力。
A polar molecule has both dispersion and dipole-dipole forces. · 极性分子既有色散力又有偶极-偶极作用力。
Why does water boil at a higher temperature than $\text{H}_2\text{S}$?
- Water has hydrogen bonds (H on O); $\text{H}_2\text{S}$ does not.
- The stronger attraction takes more energy to break, so water boils higher.
为什么水的沸点比 $\text{H}_2\text{S}$ 高?
- 水有氢键(H 连在 O 上);$\text{H}_2\text{S}$ 没有。
- 更强的吸引断开需要更多能量,所以水沸点更高。
When a molecular liquid boils, what breaks? · 当分子液体沸腾时，什么被破坏？
Boiling separates molecules by breaking the weaker forces between them. · 沸腾通过破坏较弱的分子间作用力将分子分离。
These forces act between molecules and are much weaker than the covalent bonds within them -- boiling breaks the forces, not the bonds. All molecules have dispersion; polar ones add dipole-dipole; only H bonded to N, O, or F gives hydrogen bonding. Stronger forces mean a higher boiling point and higher viscosity.
这些作用力作用在分子之间,比分子内部的共价键弱得多——沸腾断开的是这些作用力,而不是键。所有分子都有色散;极性分子再加偶极-偶极;只有 H 连在 N、O 或 F 上才有氢键。作用力越强,沸点越高、黏度越大。
Attractions between molecules set the physical state. Every molecule has London dispersion forces (stronger for more electrons); polar molecules add dipole-dipole forces; and H bonded to N, O, or F gives the strongest, hydrogen bonding. Stronger forces raise the boiling point -- as with water.
分子之间的吸引决定物理状态。每个分子都有伦敦色散力(电子越多越强);极性分子再加偶极-偶极作用;而 H 连在 N、O 或 F 上给出最强的氢键。作用力越强,沸点越高——正如水一样。