Intramolecular Force and Potential Energy · 分子内作用力与势能
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| potential energy/pəˈtenʃl ˈenədʒi/ | 势能 | shì néng |
| bond length/bɒnd leŋθ/ | 键长 | jiàn zhǎng |
| bond energy/bɒnd ˈenədʒi/ | 键能 | jiàn néng |
The perfect distance apart
- Push two bonded atoms too close and they shove back.
- Pull them too far and they snap toward each other.
- Somewhere between sits a comfortable resting gap.
- A single curve captures this tug-of-war.
恰到好处的距离
- 把两个成键的原子推得太近,它们会反推回来。
- 把它们拉得太远,它们又会朝彼此猛地靠拢。
- 在两者之间的某处,存在一个舒适的静止间距。
- 一条曲线就抓住了这场拔河。
The bond's energy curve
- Plot the potential energy 势能 against the distance between two atoms.
- Far apart it is near zero; too close it shoots up from repulsion.
- The lowest point is the stable bond length 键长.
键的能量曲线
- 把势能对两个原子之间的距离作图。
- 相距很远时接近零;太近时因排斥而急剧上升。
- 最低点就是稳定的键长。
On a potential-energy versus distance curve, the bond length is at the... · 在势能与距离曲线上，键长位于...
The minimum is the stable separation -- the bond length. · 最小值是稳定的分离距离——即键长。
Depth means strength
- The depth of the well is the bond energy 键能, the energy to break the bond.
- A deeper well means a stronger bond.
- Breaking a bond costs energy; forming one releases it.
深度意味着强度
- 势阱的深度就是键能,即断开这个键所需的能量。
- 势阱越深,键越强。
- 断键需要能量;成键释放能量。
A deeper potential-energy well means a stronger bond. · 更深的势阱意味着更强的键。
The well depth is the bond energy needed to break the bond. · 势阱深度即为断裂该键所需的键能。
Breaking a chemical bond... · 断裂化学键...
You must supply energy to pull bonded atoms apart. · 你必须提供能量才能将成键的原子拉开。
Forming a bond releases energy. · 形成键会释放能量。
Bond formation is exothermic -- the reverse of breaking. · 成键是放热的——这是断裂过程的逆过程。
Shorter bonds, stronger bonds
- More shared pairs (a higher bond order) pull the atoms closer.
- A double bond is shorter and stronger than a single bond.
- So bond length and bond strength move in opposite directions.
键越短,键越强
- 共享的电子对越多(键级越高),原子被拉得越近。
- 双键比单键更短、更强。
- 所以键长和键强方向相反。
Compared with a single bond, a double bond between the same atoms is... · 与单键相比，相同原子间的双键...
More shared pairs pull the atoms closer and hold them more tightly. · 更多的共享对将原子拉得更近并使其结合更紧密。
As bond order rises, bond length gets shorter and bond strength gets . · 随着键级升高，键长变短，键强度变得。
Shorter bonds are stronger, so strength increases as length decreases. · 较短的键更强，因此强度随长度减小而增加。
Compare a C--C single bond with a C=C double bond.
- The double bond has more shared electrons.
- It is shorter and needs more energy to break, so it is stronger.
比较 C--C 单键和 C=C 双键。
- 双键有更多共享电子。
- 它更短,断开需要更多能量,所以更强。
Reading the potential-energy curve · 解读势能曲线
As two atoms approach, their potential energy changes. Match each region of the curve to what the atoms are doing. · 当两个原子靠近时，其势能发生变化。将曲线的每个区域与原子的行为相匹配。
The bottom of the well is the natural bond length, where attraction and repulsion balance -- not where the energy is zero. Breaking a bond always requires energy (endothermic); forming one always releases it (exothermic). And a deeper well means a stronger and shorter bond, all together.
势阱的底部是自然键长,在那里吸引与排斥平衡——而不是能量为零之处。断键总是需要能量(吸热);成键总是释放能量(放热)。而且势阱越深意味着键越强又越短,一并出现。
A bond's potential energy curve dips to a minimum at the bond length, where attraction and repulsion balance. The depth of that well is the bond energy needed to break the bond. More shared pairs pull atoms closer, so higher-order bonds are both shorter and stronger.
键的势能曲线在键长处降到最低,在那里吸引与排斥平衡。势阱的深度是断键所需的键能。共享的电子对越多,原子被拉得越近,所以键级越高的键既更短又更强。