📚 Making Salts – Acids and Metals | 用酸和金属制盐
When a reactive metal is added to an acid, the mixture fizzes and the metal slowly disappears. This reaction produces a salt and hydrogen gas. In this article, you will learn how to describe the reaction between acids and metals, predict the name of the salt, test for hydrogen, and carry out the practical safely.
将活泼金属加入酸中时，混合物会冒泡，金属慢慢消失。这个反应生成盐和氢气。本文将学习如何描述酸与金属的反应、预测盐的名称、检验氢气以及安全地进行实验。
1. What Is a Salt? | 什么是盐？
A salt is a compound formed when the hydrogen in an acid is replaced by a metal. The name 'salt' does not only mean table salt; table salt is sodium chloride, but there are many other salts such as zinc chloride, magnesium sulfate and potassium nitrate. Most salts are solid crystals at room temperature, and they are often made by reacting an acid with a metal, a base or a carbonate.
盐是酸中的氢被金属取代后形成的化合物。“盐”不仅仅指食盐；食盐是氯化钠，但还有许多其他盐，如氯化锌、硫酸镁和硝酸钾。大多数盐在室温下是固体晶体，它们通常通过酸与金属、碱或碳酸盐反应制得。
2. The General Reaction: Acid + Metal | 一般反应：酸 + 金属
The general reaction between an acid and a metal can be written as:
酸与金属之间的一般反应可以写作：
acid + metal → salt + hydrogen
In this reaction the metal pushes out the hydrogen from the acid. For example, magnesium reacts with hydrochloric acid to make magnesium chloride and hydrogen gas. You see bubbles of hydrogen and the metal gets smaller. The test tube feels warm because the reaction also releases heat energy.
在这个反应中，金属把氢从酸中赶出来。例如，镁与盐酸反应生成氯化镁和氢气。你会看到氢气泡，金属逐渐变小。试管会感觉发热，因为反应还会释放热能。
The equation for this example is:
这个例子的化学方程式是：
Mg + 2HCl → MgCl₂ + H₂
Hydrogen gas is produced as bubbles, and the salt remains dissolved in the water from the acid. If you evaporate the water, the salt appears as solid crystals.
氢气以气泡形式产生，盐则溶解在酸的水中。如果蒸发水分，盐就会以固体晶体形式出现。
3. Word Equation Pattern | 文字方程式规律
The word equation follows a clear pattern. The first part of the salt name comes from the metal, and the second part comes from the acid. For hydrochloric acid the salt ends in 'chloride'; for sulfuric acid it ends in 'sulfate'; for nitric acid it ends in 'nitrate'.
文字方程式遵循清晰的规律。盐名称的前半部分来自金属，后半部分来自酸。盐酸生成的盐以“氯化”结尾；硫酸生成的盐以“硫酸”结尾；硝酸生成的盐以“硝酸”结尾。
You can think of the acid as carrying an ending that it gives to the salt. The metal simply keeps its own name at the front. So zinc and sulfuric acid make zinc sulfate, while zinc and hydrochloric acid make zinc chloride.
你可以把酸看成携带了一个结尾，并把这个结尾交给盐。金属只需把自己的名称放在前面。因此，锌和硫酸生成硫酸锌，而锌和盐酸生成氯化锌。
4. Choosing the Acid | 选择酸
The acid you choose decides the salt ending. Use the table below to predict the salt made in a reaction.
你选择的酸决定了盐的名称结尾。用下表预测反应生成的盐。
| Acid | 酸 | Salt ending | 盐名结尾 | Example salt | 示例盐 |
|---|---|---|
| Hydrochloric acid | 盐酸 | chloride | 氯化物 | sodium chloride | 氯化钠 |
| Sulfuric acid | 硫酸 | sulfate | 硫酸盐 | magnesium sulfate | 硫酸镁 |
| Nitric acid | 硝酸 | nitrate | 硝酸盐 | potassium nitrate | 硝酸钾 |
Remember: hydrochloric acid makes chloride salts, not chlorine salts. Sulfuric acid makes sulfate salts, not sulfur salts. This is a common naming pattern in chemistry.
记住：盐酸生成氯化物盐，而不是氯盐；硫酸生成硫酸盐，而不是硫盐。这是化学中常见的命名规律。
5. Which Metals React? | 哪些金属能反应？
Not all metals react with acids. Only metals that are more reactive than hydrogen will react with dilute acids. Reactive metals such as magnesium, zinc and iron fizz quickly and produce hydrogen. Copper and silver are less reactive than hydrogen, so they do not react with dilute acids. Gold does not react either.
并非所有金属都能与酸反应。只有比氢活泼的金属才会与稀酸反应。镁、锌和铁等活泼金属会迅速冒泡并产生氢气。铜和银的活泼性不如氢，因此不与稀酸反应。金也不反应。
Potassium, sodium and lithium are very reactive. They react explosively with acids, so schools do not use them for making salts. In the laboratory, safe metals such as magnesium, zinc and small pieces of iron are normally chosen.
钾、钠和锂非常活泼。它们与酸反应会爆炸，所以学校不用它们来制盐。在实验室中，通常选择镁、锌和小块铁等安全的金属。
The more reactive a metal is, the faster and more vigorous the reaction. Magnesium reacts very quickly with dilute hydrochloric acid, while iron reacts more slowly.
金属越活泼，反应越快、越剧烈。镁与稀盐酸反应非常快，而铁反应较慢。
6. Testing for Hydrogen Gas | 检验氢气
Hydrogen gas is formed in this reaction. To test for hydrogen, hold a lighted splint at the mouth of the test tube. Hydrogen burns quickly with oxygen in the air and makes a 'squeaky pop' sound. This test is used to confirm the gas is hydrogen, not carbon dioxide or oxygen.
这个反应会产生氢气。检验氢气时，把一根点燃的木条放在试管口。氢气与空气中的氧气迅速燃烧，发出“噗”的爆鸣声。这个测试用来确认气体是氢气，而不是二氧化碳或氧气。
The squeaky pop happens because hydrogen is a very flammable gas. When a small amount of hydrogen mixes with air and is lit, it explodes gently inside the test tube, producing the sound.
爆鸣声的产生是因为氢气是一种非常易燃的气体。少量氢气与空气混合后被点燃时，会在试管内轻微爆燃，从而发出声音。
7. Naming Salts | 盐的命名
acid → zinc chloride + hydrogen. Magnesium + sulfuric acid → magnesium sulfate + hydrogen.
命名盐时，先写金属名称，再加上酸的结尾。盐酸生成氯化物；硫酸生成硫酸盐；硝酸生成硝酸盐。例如，锌 + 盐酸 → 氯化锌 + 氢气。镁 + 硫酸 → 硫酸镁 + 氢气。
The same pattern works with symbol equations. Magnesium reacts with sulfuric acid as follows:
同样的规律也适用于化学方程式。镁与硫酸反应如下：
Mg + H₂SO₄ → MgSO₄ + H₂
Zinc reacts with hydrochloric acid as follows:
锌与盐酸反应如下：
Zn + 2HCl → ZnCl₂ + H₂
In each case, the salt formula contains the metal and the non-metal part from the acid. The hydrogen atoms pair up to form H₂ gas.
在每种情况下，盐的化学式都包含金属和来自酸的非金属部分。氢原子结合成对，形成氢气分子 H₂。
8. Worked Examples | 示例分析
chloride and hydrogen. Word equation: zinc + hydrochloric acid → zinc chloride + hydrogen.
示例 1：写出锌与盐酸反应的文字方程式。金属是锌，盐酸生成氯化物盐。产物是氯化锌和氢气。文字方程式：锌 + 盐酸 → 氯化锌 + 氢气。
ate and hydrogen. Word equation: magnesium + sulfuric acid → magnesium sulfate + hydrogen.
示例 2：写出镁与硫酸反应的文字方程式。金属是镁，硫酸生成硫酸盐。产物是硫酸镁和氢气。文字方程式：镁 + 硫酸 → 硫酸镁 + 氢气。
chloride and hydrogen. Word equation: iron + hydrochloric acid → iron chloride + hydrogen.
示例 3：写出铁与盐酸反应的文字方程式。金属是铁，盐酸生成氯化物盐。产物是氯化铁和氢气。文字方程式：铁 + 盐酸 → 氯化铁 + 氢气。
+ metal → salt + hydrogen. Once you know the metal and the acid, you can predict the salt.
请注意，每次都会出现相同的规律：酸 + 金属 → 盐 + 氢气。只要知道金属和酸，就能预测生成的盐。
9. Practical Method: Making a Salt | 实验方法：制盐
To make
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