📚 Reactions of Metals with Acids: KS3 CIE Mark Scheme Guide | 金属与酸反应：KS3 CIE 评分标准指南
Understanding how metals react with acids is a core KS3 CIE Chemistry topic. This guide explains exactly what the mark scheme expects, from word equations and observations to the hydrogen gas test and common errors. Use it alongside past-paper questions to sharpen your answers.
理解金属与酸的反应是 KS3 CIE 化学的核心主题。本指南从文字方程式、实验现象到氢气检验和常见错误，详细说明评分标准的要求。配合历年真题使用，可以让你的答案更加精准。
1. What the Mark Scheme Rewards | 评分标准的给分点
In CIE KS3 mark schemes, examiners look for clear evidence that you can identify the products, describe observations accurately, and link reaction speed to the reactivity series. Most questions award one mark for naming the salt, one mark for naming hydrogen, and one mark for a valid observation such as fizzing or the metal dissolving.
在 CIE KS3 评分标准中，考官会看你能否清楚地识别生成物、准确描述现象，并把反应快慢与金属活动性顺序联系起来。大多数题目会给命名盐 1 分、命名氢气 1 分，以及写出合理现象（如冒泡或金属溶解）1 分。
Mark schemes also reward correct use of the word “effervescence” instead of vague terms like “gas comes out”. If the question asks for a test, you must say “lighted splint” and “squeaky pop” – simply saying “hydrogen” is usually not enough for the test mark.
评分标准还鼓励使用 “effervescence（冒泡/起泡）” 这类准确词汇，而不是 “有气体出来” 这样的模糊说法。如果题目要求检验方法，你必须写出 “点燃的木条” 和 “发出尖锐爆鸣声”——只写 “氢气” 通常拿不到检验这一分。
2. Core Word Equation | 核心文字方程式
The general word equation for a metal reacting with an acid is:
金属与酸反应的一般文字方程式是：
metal + acid → salt + hydrogen
This equation is the backbone of almost every mark scheme. You must be able to write it from memory and then replace “metal”, “acid” and “salt” with the specific substances in the question.
这个方程式是几乎所有评分标准的基础。你必须能够默写它，然后把 “金属”、”酸” 和 “盐” 替换成题目中具体的物质。
For example, with magnesium and hydrochloric acid, the word equation becomes:
例如，镁和盐酸反应时，文字方程式变为：
magnesium + hydrochloric acid → magnesium chloride + hydrogen
Notice that the salt takes its name from the metal and the acid: hydrochloric acid gives a chloride, sulfuric acid gives a sulfate, and nitric acid gives a nitrate.
注意盐的名称来自金属和酸：盐酸生成氯化物，硫酸生成硫酸盐，硝酸生成硝酸盐。
3. Using the Reactivity Series | 使用金属活动性顺序
Mark schemes expect you to use the reactivity series to predict whether a reaction will happen and how fast it will be. More reactive metals, such as magnesium, react vigorously with dilute acids, while less reactive metals, such as iron or zinc, react more slowly.
评分标准要求你使用金属活动性顺序来预测反应是否会发生以及反应的快慢。较活泼的金属（如镁）与稀酸反应剧烈，而较不活泼的金属（如铁或锌）反应较慢。
A common KS3 order you should know is: potassium, sodium, calcium, magnesium, aluminium, zinc, iron, lead, copper, silver, gold. Copper, silver and gold are below hydrogen in the series, so they do not react with dilute acids to produce hydrogen.
你需要掌握 KS3 常见的活动性顺序：钾、钠、钙、镁、铝、锌、铁、铅、铜、银、金。铜、银和金在顺序中位于氢之后，因此它们不能与稀酸反应生成氢气。
In a mark scheme, saying “copper does not react because it is less reactive than hydrogen” scores full marks. Saying “copper is too unreactive” may only score partial marks unless you compare it to hydrogen.
在评分标准中，回答 “铜不反应，因为它的活动性弱于氢” 可以得满分。如果只回答 “铜太不活泼” 但没有与氢比较，通常只能得部分分数。
4. Observations to Describe | 需要描述的实验现象
When a reactive metal is added to dilute acid, the mark scheme accepts several key observations: bubbles of gas, the metal becoming smaller or dissolving, the mixture getting warmer, and sometimes a colour change in the solution.
当把活泼金属加入稀酸时，评分标准接受以下关键现象：有气泡冒出、金属变小或溶解、混合物温度升高，有时溶液颜色发生变化。
Use the phrase “effervescence” to describe rapid bubbling. For magnesium with dilute hydrochloric acid, a high-level answer would say: “vigorous effervescence, magnesium dissolves, colourless solution remains, and the test tube feels warm.”
用 “effervescence” 来描述快速冒泡。对于镁与稀盐酸的反应，高水平答案会写：”剧烈冒泡，镁溶解，溶液保持无色，试管摸起来发热。”
Do not say “a gas is produced” as your only observation unless the question specifically asks for a product. The observation mark is about what you see or feel, not the chemical name of the gas.
不要把 “产生了气体” 作为唯一的实验现象，除非题目明确问的是生成物。现象分考的是你看到或感觉到什么，而不是气体的化学名称。
5. Testing for Hydrogen Gas | 氢气的检验
The test for hydrogen gas is a common one-mark or two-mark question. You must state that a lighted splint is held at the mouth of the test tube and that the gas burns with a squeaky pop.
氢气的检验是常见的 1 分或 2 分题。你必须回答：将点燃的木条放在试管口，气体会燃烧并发出尖锐的爆鸣声。
Mark schemes usually award one mark for “lighted splint” and one for “squeaky pop”. If
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