Edexcel A-Level Chemistry Topic 14 & 16 Combined: Redox Equilibria and Kinetics II | 爱德思 A-Level 化学第 14 与 16 专题综合：氧化还原平衡与动力学 II

📚 Edexcel A-Level Chemistry Topic 14 & 16 Combined: Redox Equilibria and Kinetics II | 爱德思 A-Level 化学第 14 与 16 专题综合：氧化还原平衡与动力学 II

This revision guide brings together Edexcel A-Level Chemistry Topic 14 (Redox II) and Topic 16 (Kinetics II). Both topics are heavily examined in Paper 2 and often appear in combined data-analysis and mechanism questions.

本复习指南将爱德思 A-Level 化学第 14 专题（氧化还原 II）与第 16 专题（动力学 II）合并讲解。两个专题在 Paper 2 中考查频率很高，并且经常以数据分析与反应机理综合题的形式出现。

1. Why Combine Redox and Kinetics? | 为什么综合氧化还原与动力学？

Topic 14 extends redox ideas to quantitative electrode potentials and cells, while Topic 16 develops the quantitative description of reaction rates. Combining them helps you link energy, feasibility and mechanism.

第 14 专题将氧化还原概念拓展到定量的电极电势与原电池，第 16 专题则建立反应速率的定量描述。把两者结合起来，有助于你建立能量、可行性与机理之间的联系。

In an exam, you may be given a redox reaction, asked to calculate its cell potential, then asked how changing a reactant concentration affects the rate. This guide treats these skills as one connected toolkit.

在考试中，你可能先写出一个氧化还原反应并计算电池电动势，再分析反应物浓度变化如何影响速率。本指南将把这些技能视为一套相互关联的工具。

2. Standard Electrode Potentials | 标准电极电势

A standard electrode potential E° is the potential difference between a half-cell and the standard hydrogen electrode, measured at 298 K, 100 kPa and 1.0 mol dm⁻³ ion concentration. Its value is quoted as a reduction potential.

标准电极电势 E° 是指某半电池与标准氢电极之间的电势差，测定条件为 298 K、100 kPa 和 1.0 mol dm⁻³ 离子浓度。其数值通常以还原电势给出。

The more negative the E°, the stronger the reducing agent; the more positive the E°, the stronger the oxidising agent. In a cell, the half-cell with the more negative E° is the anode and undergoes oxidation.

E° 越负，还原剂越强；E° 越正，氧化剂越强。在原电池中，E° 更负的半电池为负极（阳极），发生氧化反应。

• Standard hydrogen electrode: 2H⁺ + 2e⁻ ⇌ H₂, E° = 0.00 V
• Negative E°: stronger reducing agent; positive E°: stronger oxidising agent

English: Remember that the sign of E° refers to the reduction process. A negative E° means the reduced form is a strong reducing agent.

中文：请记住，E° 的符号对应还原过程。负的 E° 表示其还原态是强还原剂。

3. Cell Potential and Feasibility | 电池电动势与反应可行性

To calculate the cell potential, use E°cell = E°(cathode) − E°(anode). If both values are written as reduction potentials, this equation always gives the spontaneous direction when E°cell is positive.

计算电池电动势时使用 E°cell = E°(cathode) − E°(anode)。如果两个数值都写成还原电势，当 E°cell 为正时，该方向即为自发反应方向。

E°cell = E°(cathode) − E°(anode)

For Zn²⁺/Zn E° = −0.76 V and Cu²⁺/Cu E° = +0.34 V, the feasible cell is Cu²⁺ + Zn → Cu + Zn²⁺, with E°cell = +0.34 − (−0.76) = +1.10 V.

例如 Zn²⁺/Zn 的 E° = −0.76 V，Cu²⁺/Cu 的 E° = +0.34 V，可自发进行的电池反应为 Cu²⁺ + Zn → Cu + Zn²⁺，E°cell = +0.34 − (−0.76) = +1.10 V。

A positive E°cell corresponds to a negative ΔG, so the reaction is thermodynamically feasible. The relationship is ΔG = −nFE°cell.

正的 E°cell 对应负的 ΔG，因此反应在热力学上可行。其关系式为 ΔG = −nFE°cell。