Quantitative Electrolysis | 定量电解

📚 Quantitative Electrolysis | 定量电解

Quantitative electrolysis links electric current, time, and the charge on one mole of electrons to the mass, volume, or concentration of products formed at electrodes. By using Faraday’s laws and balanced half-equations, you can predict exactly how much metal is deposited or how much gas is evolved.

定量电解将电流、时间和每摩尔电子的电荷与电极上产物的质量、体积或浓度联系起来。利用法拉第定律和配平的半反应，你可以准确预测沉积多少金属或放出多少气体。

1. Electrolysis and Charge | 电解与电荷

Electrolysis is the decomposition of a molten or dissolved ionic compound by a direct electric current. Oxidation occurs at the anode and reduction occurs at the cathode.

电解是直流电使熔融或溶解的离子化合物分解的过程。阳极发生氧化，阴极发生还原。

The quantity of product formed depends on the total charge passed through the cell. The charge Q is measured in coulombs (C).

生成的产物量取决于通过电池的总电荷。电荷 Q 的单位是库仑（C）。

If a steady current I in amperes (A) flows for a time t in seconds (s), the total charge is given by the equation below.

如果稳定电流 I 以安培（A）为单位，时间 t 以秒（s）为单位，则总电荷由下式给出。

Q = I × t

Always convert time to seconds before using this equation. Common conversions include 1 hour = 3600 s and 1 minute = 60 s.

使用该式前一定要把时间换算成秒。常见换算是 1 小时 = 3600 s，1 分钟 = 60 s。

2. Faraday’s First Law | 法拉第第一定律

Faraday’s first law states that the mass of a substance produced at an electrode is directly proportional to the total electric charge passed through the electrolyte.

法拉第第一定律指出，电极上生成物质的质量与通过电解质的总电荷成正比。

This is because each ion requires a fixed number of electrons to become a neutral atom or molecule. More charge means more electrons and therefore more product.

这是因为每个离子变成中性原子或分子需要固定数量的电子。电荷越多，电子越多，产物也越多。

For example, if a copper(II) sulfate solution is electrolysed, doubling the current with the same time, or doubling the time with the same current, doubles the mass of copper deposited.

例如，电解硫酸铜(II)溶液时，在其他条件不变的情况下，电流加倍或时间加倍都会使析出的铜质量加倍。

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