ΔG 吉布斯自由能计算器（ΔG = ΔH − TΔS）Gibbs Free Energy Calculator (ΔG = ΔH − TΔS)

使用说明与常见问题How-to & FAQ

「吉布斯自由能计算器（ΔG = ΔH − TΔS）」是什么？What is the Gibbs Free Energy Calculator (ΔG = ΔH − TΔS) tool?

由 ΔH（kJ/mol）、ΔS（J/(mol·K) 或 kJ/(mol·K)）和温度（K 或 °C）算出 ΔG，判断是否自发，给出转变温度 T = ΔH/ΔS 和平衡常数 K = e^(−ΔG/RT)。本地处理。Work out ΔG from ΔH (kJ/mol), ΔS (J/(mol·K) or kJ/(mol·K)) and the temperature (K or °C), see whether the reaction is spontaneous, and get the crossover temperature T = ΔH/ΔS and the equilibrium constant K = e^(−ΔG/RT). Processed locally.

如何使用「吉布斯自由能计算器（ΔG = ΔH − TΔS）」？How do I use the Gibbs Free Energy Calculator (ΔG = ΔH − TΔS) tool?

在「吉布斯自由能计算器（ΔG = ΔH − TΔS）」中，填写「ΔH（kJ/mol）」、「ΔS」、「ΔS 单位」、「温度」、「温度单位」等参数，结果会随输入实时计算并显示在下方。In the Gibbs Free Energy Calculator (ΔG = ΔH − TΔS): Fill in "ΔH (kJ/mol)", "ΔS", "ΔS unit", "Temperature", "Temperature unit"; results are recalculated instantly as you type.

单位要注意什么？What about units?

ΔH 一般用 kJ/mol，而 ΔS 表里常用 J/(mol·K)，两者差 1000 倍，这是最常见的错误。本页让你选 ΔS 的单位，并自动换算。温度必须用开尔文计算，选 °C 时会加 273.15。ΔH is usually in kJ/mol while tables give ΔS in J/(mol·K), a factor of 1000 apart, which is the most common mistake. Pick the ΔS unit here and it is converted for you. The calculation needs kelvin; choosing °C adds 273.15.

转变温度是什么？What is the crossover temperature?

当 ΔH 和 ΔS 同号时，ΔG 在 T = ΔH/ΔS 处变号。两者都为正时高于该温度自发（熵驱动），两者都为负时低于该温度自发（焓驱动）。When ΔH and ΔS have the same sign, ΔG changes sign at T = ΔH/ΔS. If both are positive the reaction is spontaneous above that temperature (entropy-driven); if both are negative it is spontaneous below it (enthalpy-driven).

K 是怎么来的？Where does K come from?

标准吉布斯自由能和平衡常数的关系是 ΔG° = −RT ln K，R = 8.314 J/(mol·K)。输入标准值（ΔH°、ΔS°）时得到的就是该温度下的标准平衡常数。The standard Gibbs energy and the equilibrium constant are linked by ΔG° = −RT ln K with R = 8.314 J/(mol·K). With standard values (ΔH°, ΔS°) the result is the standard equilibrium constant at that temperature.

能举个计算实例吗？Can you show a worked example?

例如在「吉布斯自由能计算器（ΔG = ΔH − TΔS）」中填 ΔH（kJ/mol） = -100，ΔS = -50，ΔS 单位 = J/(mol·K)，温度 = 298，温度单位 = K，结果区显示：ΔG：-85.1 kJ/mol；温度：298 K；是否自发：ΔG < 0：在该温度下自发；转变温度 T = ΔH/ΔS：2,000 K（1,726.85 °C） · 低于此温度自发；平衡常数 K = e^(−ΔG/RT)：824,858,468,303,900；ℹ ΔG = ΔH − TΔS；ΔS 按 J/(mol·K) 输入时先除以 1000 换成 kJFor example, entering ΔH (kJ/mol) = -100, ΔS = -50, ΔS unit = J/(mol·K), Temperature = 298, Temperature unit = K in the Gibbs Free Energy Calculator (ΔG = ΔH − TΔS) gives: ΔG: -85.1 kJ/mol; Temperature: 298 K; Spontaneous?: ΔG < 0: spontaneous at this temperature; Crossover temperature T = ΔH/ΔS: 2,000 K (1,726.85 °C) · spontaneous below it; Equilibrium constant K = e^(−ΔG/RT): 824,858,468,303,900; ℹ ΔG = ΔH − TΔS; a ΔS in…

哪些输入会被检查？Which inputs are validated?

「吉布斯自由能计算器（ΔG = ΔH − TΔS）」会检查这些输入——「ΔH（kJ/mol）」、「ΔS」、「温度」：所选方式用到时必须填写；绝对值超过 10¹⁵ 的数也会被拒绝。不符合时结果区显示具体提示，不会给出数字。The Gibbs Free Energy Calculator (ΔG = ΔH − TΔS) checks its inputs — "ΔH (kJ/mol)", "ΔS", "Temperature": required when the chosen option uses it; numbers above 10¹⁵ in absolute value are rejected too. When a value fails, the result area names the problem instead of showing a number.

有哪些选项可以调整？What options can I adjust?

「吉布斯自由能计算器（ΔG = ΔH − TΔS）」的设置：「ΔH（kJ/mol）」默认 -92.2；「ΔS」默认 -198.7；「ΔS 单位」可选 J/(mol·K)、kJ/(mol·K)（默认 J/(mol·K)）；「温度」默认 298.15；「温度单位」可选 K、°C（默认 K）。每次生成结果都按当前设置处理。Settings in the Gibbs Free Energy Calculator (ΔG = ΔH − TΔS) — "ΔH (kJ/mol)" default -92.2; "ΔS" default -198.7; "ΔS unit": J/(mol·K), kJ/(mol·K) (default J/(mol·K)); "Temperature" default 298.15; "Temperature unit": K, °C (default K). The result always uses the current settings.

计算结果可以用于作业或工程吗？Can I use the results for homework or engineering?

「吉布斯自由能计算器（ΔG = ΔH − TΔS）」使用教科书标准公式（公式写在说明和常见问题中），适合学习和估算核对；涉及安全的工程设计请以规范和实测为准。The Gibbs Free Energy Calculator (ΔG = ΔH − TΔS) uses standard textbook formulas (given in the description and FAQ), which is good for learning and checking estimates; for safety-critical engineering follow codes and measured values.

「吉布斯自由能计算器（ΔG = ΔH − TΔS）」免费吗？需要注册吗？Is the Gibbs Free Energy Calculator (ΔG = ΔH − TΔS) free? Do I need an account?

「吉布斯自由能计算器（ΔG = ΔH − TΔS）」完全免费，无需注册或安装，打开网页即可使用，手机和电脑都能用；输入的内容只在你的浏览器本地处理。The Gibbs Free Energy Calculator (ΔG = ΔH − TΔS) is completely free with no sign-up or install and works on phones and desktops; what you enter is processed only in your browser.