Gibbs free energy change · 吉布斯自由能变
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| Gibbs free energy/ɡɪbz friː ˈenədʒi/ | 吉布斯自由能 | jí bù sī zì yóu néng |
| enthalpy/enˈθælpi/ | 焓 | hán |
| entropy/ˈentrəpi/ | 熵 | shāng |
| feasible/ˈfiːzɪbl/ | 可行 | kě xíng |
| kelvin/ˈkelvɪn/ | 开尔文 | kāi ěr wén |
Will it actually happen?
- Gibbs free energy 吉布斯自由能 decides whether a reaction can happen on its own.
- It combines enthalpy 焓 and entropy 熵 with temperature.
- A negative $\Delta G$ means the reaction is feasible 可行.
它真的会发生吗?
- 吉布斯自由能(Gibbs free energy)决定一个反应是否能自己发生。
- 它把焓和熵与温度结合起来。
- 一个负的 $\Delta G$ 意味着反应是可行的。
Gibbs free energy lab · 吉布斯自由能实验室
deltaG = deltaH - T deltaS
Move temperature and see when deltaG becomes negative. · 移动温度,看 deltaG 何时变成负的。
A reaction is feasible when the Gibbs free energy change ΔG is ______. · 一个反应在吉布斯自由能变 ΔG 是______时可行。
ΔG = ΔH − TΔS. · ΔG = ΔH − TΔS。
The equation
- $T$ is the temperature in kelvin 开尔文.
- A reaction is feasible (can happen) when $\Delta G \leq 0$.
When a reaction is feasible from the signs of enthalpy and entropy change
方程
- $T$ 是以开尔文(kelvin)表示的温度。
- 一个反应在 $\Delta G \leq 0$ 时是可行的(能发生)。
从焓和熵变的符号看一个反应何时可行
The Gibbs free energy change is calculated as: · 吉布斯自由能变计算为:
ΔG° = ΔH° − TΔS°, with T in kelvin. · ΔG° = ΔH° − TΔS°,T 以开尔文。
A reaction is feasible when: · 一个反应在以下哪种情况下可行:
A reaction can happen on its own when ΔG ≤ 0. · 一个反应在 ΔG ≤ 0 时能自己发生。
Match each Gibbs idea. · 匹配每个吉布斯概念。
Each item links the term to its correct meaning. · 每一项把术语链接到它正确的含义。
Feasibility and temperature
| $\Delta H$ | $\Delta S$ | Feasible |
|---|---|---|
| negative | positive | at all temperatures |
| positive | positive | only at high temperature |
| negative | negative | only at low temperature |
| positive | negative | never |
- The changeover temperature is found by setting $\Delta G = 0$, giving $T = \dfrac{\Delta H}{\Delta S}$.
A gaseous atom gains an electron, usually releasing energy
可行性和温度
| $\Delta H$ | $\Delta S$ | 可行 |
|---|---|---|
| 负 | 正 | 在所有温度 |
| 正 | 正 | 只在高温 |
| 负 | 负 | 只在低温 |
| 正 | 负 | 从不 |
- 转变温度通过设 $\Delta G = 0$ 找到,给出 $T = \dfrac{\Delta H}{\Delta S}$。
A reaction with negative ΔH and positive ΔS is feasible: · 一个有负 ΔH 和正 ΔS 的反应可行:
With −ΔH and +ΔS, ΔG = ΔH − TΔS is always negative, so it is feasible at all temperatures. · 有 −ΔH 和 +ΔS,ΔG = ΔH − TΔS 总是负的,所以它在所有温度可行。
The changeover temperature (where feasibility begins) is found by setting: · 转变温度(可行性开始的地方)通过设以下哪个找到:
At ΔG = 0 the reaction is on the verge of feasibility; rearranging gives T = ΔH/ΔS. · 在 ΔG = 0 时反应在可行性的边缘;重排给出 T = ΔH/ΔS。
A feasibility calculation
Worked example. ΔG = ΔH − TΔS. If ΔH = +20 kJ/mol and TΔS = +30 kJ/mol, then ΔG = 20 − 30 = −10 kJ/mol, so the reaction is feasible.
一个可行性计算
例题。 ΔG = ΔH − TΔS。如果 ΔH = +20 kJ/mol 且 TΔS = +30 kJ/mol,那么 ΔG = 20 − 30 = −10 kJ/mol,所以反应是可行的。
You've got it
- $\Delta G^{\ominus} = \Delta H^{\ominus} - T\Delta S^{\ominus}$ (T in kelvin)
- a reaction is feasible when $\Delta G \leq 0$
- $-\Delta H$ & $+\Delta S$ → feasible at all T; $+\Delta H$ & $-\Delta S$ → never
- changeover temperature: set $\Delta G = 0$, so $T = \dfrac{\Delta H}{\Delta S}$
你掌握了
- $\Delta G^{\ominus} = \Delta H^{\ominus} - T\Delta S^{\ominus}$(T 以开尔文)
- 一个反应在 $\Delta G \leq 0$ 时是可行的
- $-\Delta H$ 和 $+\Delta S$ → 在所有 T 可行;$+\Delta H$ 和 $-\Delta S$ → 从不
- 转变温度:设 $\Delta G = 0$,所以 $T = \dfrac{\Delta H}{\Delta S}$