📚 KS3 CIE Word Equations: Answers | KS3 CIE 文字方程式答案
Word equations are a simple way to describe chemical reactions using the names of substances instead of formulas. This revision guide gives you clear answers, worked examples, complete answer sets and the common CIE KS3 question styles, so you can check your understanding, correct your mistakes and improve your exam answers.
文字方程式是用物质名称（而不是化学式）描述化学反应的简单方法。本复习指南为你提供清晰的答案、解题示例、完整的答案清单以及常见的 CIE KS3 题型，帮助你检查理解、纠正错误并提高考试答题质量。
1. What Is a Word Equation? | 什么是文字方程式
A word equation is a summary of a chemical reaction. It uses the names of the chemicals instead of formulas or symbols.
文字方程式是化学反应的概括。它使用化学物质的名称，而不是化学式或符号。
In every word equation, the starting chemicals are called reactants. The chemicals made at the end are called products.
在每个文字方程式中，起始的化学物质称为反应物。最后生成的化学物质称为生成物。
The reactants are written on the left of an arrow, and the products are written on the right. The arrow means 'reacts to form' or 'produces'.
反应物写在箭头的左边，生成物写在箭头的右边。箭头表示"反应生成"或"产生"。
mple: copper + oxygen → copper oxide. Reactants: copper and oxygen. Product: copper oxide.
示例：铜 + 氧气 → 氧化铜。反应物：铜和氧气。生成物：氧化铜。
A word equation does not show how many atoms or molecules take part. It only shows which substances are used up and which new substances are made.
文字方程式不显示参与反应的原子或分子数量。它只说明哪些物质被消耗、哪些新物质被生成。
2. Key Rules for Writing Word Equations | 书写文字方程式的关键规则
Always use chemical names in word equations, not symbols such as Cu or O₂, unless the question asks for a symbol equation.
在文字方程式中始终使用化学名称，而不是像 Cu 或 O₂ 这样的符号，除非题目要求写符号方程式。
Write the reactants before the arrow. If there are two reactants, separate them with a plus sign. Do the same for two or more products.
将反应物写在箭头之前。如果有两种反应物，用加号隔开。两种或更多生成物也同样处理。
Keep the same names on both sides of the arrow. Do not try to balance a word equation by changing a name or adding numbers.
箭头两边保持相同的名称。不要试图通过改变名称或添加数字来配平文字方程式。
gen chloride. The plus sign separates the reactants, and the arrow shows the direction of change.
示例：氢气 + 氯气 → 氯化氢。加号将反应物隔开，箭头表示变化的方向。
Use the standard English names that appear in your CIE textbook, and check the spelling of longer names such as 'hydrochloric acid' and 'carbon dioxide'.
使用 CIE 教材中的标准英文名称，并检查较长名称的拼写，例如 "hydrochloric acid"（盐酸）和 "carbon dioxide"（二氧化碳）。
- Reactants on the left, products on the right | 反应物在左，生成物在右
- Plus signs between separate substances | 不同物质之间用加号
- Names only, never formulas | 只用名称，绝不用化学式
- No balancing numbers at KS3 | KS3 阶段不写配平数字
3. Reading the Arrow, Plus Signs and Conditions | 如何读箭头、加号和反应条件
The arrow is read as 'reacts to form' or 'produces'. It always points from reactants to products, never backwards.
箭头读作"反应生成"或"产生"。它始终由反应物指向生成物，绝不反向。
A plus sign on the left means the substances react together. A plus sign on the right means more than one product is made.
左边的加号表示这些物质一起反应。右边的加号表示生成了不止一种物质。
Reaction conditions are written above or below the arrow. Common conditions are heat, light, a catalyst or electricity.
反应条件写在箭头的上方或下方。常见条件有加热、光照、催化剂或通电。
State symbols may be added in brackets after each name: (s) for solid, (l) for liquid, (g) for gas and (aq) for aqueous solution.
可在每个名称后用括号加注状态符号：(s) 表示固体，(l) 表示液体，(g) 表示气体，(aq) 表示水溶液。
Example: calcium carbonate (s) → calcium oxide (s) + carbon dioxide (g), with 'heat' written above the arrow.
示例：碳酸钙 (s) → 氧化钙 (s) + 二氧化碳 (g)，"heat"（加热）写在箭头上方。
If a question says 'dilute hydrochloric acid', write the full name including 'dilute' only when the mark scheme requires it; otherwise 'hydrochloric acid' is enough.
如果题目写"稀盐酸"，只有在评分标准要求时才需写出 "dilute"；否则写 "hydrochloric acid" 即可。
4. Common Word Equations with Answers (Set 1) | 常见文字方程式及答案（第一组）
Below are common CIE KS3 word equations. Check each answer and practise writing it from memory until you can recall it quickly.
以下是 CIE KS3 常见的文字方程式。检查每个答案，并练习默写，直到你能快速回忆出来。
Answer 1: hydrogen + oxygen → water.
答案 1：氢气 + 氧气 → 水。
Answer 2: magnesium + oxygen → magnesium oxide.
答案 2：镁 + 氧气 → 氧化镁。
Answer 3: carbon + oxygen → carbon dioxide.
答案 3：碳 + 氧气 → 二氧化碳。
Answer 4: iron + sulfur → iron sulfide (heated).
答案 4：铁 + 硫 → 硫化亚铁（需加热）。
Answer 5: hydrogen + chlorine → hydrogen chloride.
答案 5：氢气 + 氯气 → 氯化氢。
| Reaction | 反应 | Word equation | 文字方程式 |
| Burning hydrogen | 氢气燃烧 | hydrogen + oxygen → water |
| Burning magnesium | 镁燃烧 | magnesium + oxygen → magnesium oxide |
| Burning carbon | 碳燃烧 | carbon + oxygen → carbon dioxide |
| Heating iron and sulfur | 加热铁与硫 | iron + sulfur → iron sulfide |
5. Common Word Equations with Answers (Set 2) | 常见文字方程式及答案（第二组）
Acids, carbonates and salts appear in almost every KS3 paper. Learn these answers as a set, because the same patterns repeat.
酸、碳酸盐和盐几乎出现在每一份 KS3 试卷中。请成组记忆这些答案，因为相同的规律会反复出现。
Answer 6: magnesium + hydrochloric acid → magnesium chloride + hydrogen.
答案 6：镁 + 盐酸 → 氯化镁 + 氢气。
Answer 7: zinc + sulfuric acid → zinc sulfate + hydrogen.
答案 7：锌 + 硫酸 → 硫酸锌 + 氢气。
Answer 8: sodium hydroxide + hydrochloric acid → sodium chloride + water.
答案 8：氢氧化钠 + 盐酸 → 氯化钠 + 水。
swer 9: calcium carbonate + hydrochloric acid → calcium chloride + water + carbon dioxide.
答案 9：碳酸钙 + 盐酸 → 氯化钙 + 水 + 二氧化碳。
Answer 10: copper oxide + sulfuric acid → copper sulfate + water.
答案 10：氧化铜 + 硫酸 → 硫酸铜 + 水。
- Metal + acid → salt + hydrogen | 金属 + 酸 → 盐 + 氢气
- Acid + alkali → salt + water | 酸 + 碱 → 盐 + 水
- Acid + metal oxide → salt + water | 酸 + 金属氧化物 → 盐 + 水
- Acid + metal carbonate → salt + water + carbon dioxide | 酸 + 金属碳酸盐 → 盐 + 水 + 二氧化碳
6. Metals with Oxygen and Acids | 金属与氧气、酸的反应
xygen, a metal oxide is formed. The general word equation is metal + oxygen → metal oxide.
金属燃烧或与氧气反应时生成金属氧化物。一般文字方程式为：金属 + 氧气 → 金属氧化物。
When a reactive metal reacts with a dilute acid, a salt and hydrogen gas are produced.
活泼金属与稀酸反应时，生成一种盐和氢气。
The name of the salt comes from the metal and the acid: hydrochloric acid gives chlorides, sulfuric acid gives sulfates and nitric acid gives nitrates.
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。
Not every metal reacts. Magnesium, zinc and iron react with dilute acids and produce bubbles of hydrogen, but copper does not react with dilute hydrochloric acid.
并非所有金属都反应。镁、锌和铁与稀酸反应并产生氢气气泡，但铜不与稀盐酸反应。
Example: magnesium + sulfuric acid → magnesium sulfate + hydrogen.
示例：镁 + 硫酸 → 硫酸镁 + 氢气。
A test for hydrogen: the gas burns with a squeaky pop when a lighted splint is held at the mouth of the tube.
氢气的检验方法：将点燃的木条放在试管口，气体燃烧时发出"爆鸣声"。
7. Neutralisation and Salt Formation | 中和反应与盐的生成
Neutralisation happens when an acid reacts with an alkali (a soluble base). The products are always a salt and water.
中和反应发生在酸与碱（可溶性碱）之间。生成物始终是盐和水。
General word equation: acid + alkali → salt + water.
一般文字方程式：酸 + 碱 → 盐 + 水。
The same idea works for insoluble bases such as metal oxides and metal hydroxides.
同样的规律也适用于不溶性碱，例如金属氧化物和金属氢氧化物。
Indicators such as litmus or universal indicator can show when the acid has been exactly neutralised, because the pH moves towards 7.
石蕊或通用指示剂可以显示酸何时被恰好中和，因为 pH 值趋向 7。
Example: potassium hydroxide + nitric acid → potassium nitrate + water.
示例：氢氧化钾 + 硝酸 → 硝酸钾 + 水。
In an exam, a common question gives you the names of the acid and alkali and asks you to write the word equation. First find the two parts of the salt name, then add water as the second product.
考试中常见题目给出酸和碱的名称，要求你写出文字方程式。先确定盐的名称的两个部分，再加上第二种生成物——水。
8. Thermal Decomposition | 热分解反应
Thermal decomposition means breaking a compound down by heating it. The word 'thermal' means heat, and 'decomposition' means breaking down.
热分解是指通过加热使化合物分解。"thermal" 意为热，"decomposition" 意为分解。
Most metal carbonates decompose when heated to give a metal oxide and carbon dioxide.
大多数金属碳酸盐受热分解，生成金属氧化物和二氧化碳。
General word equation: metal carbonate → metal oxide + carbon dioxide.
一般文字方程式：金属碳酸盐 → 金属氧化物 + 二氧化碳。
Example 1: copper carbonate → copper oxide + carbon dioxide.
示例 1：碳酸铜 → 氧化铜 + 二氧化碳。
Example 2: calcium carbonate → calcium oxide + carbon dioxide.
示例 2：碳酸钙 → 氧化钙 + 二氧化碳。
Some other compounds decompose too. Hydrogen peroxide breaks down into water and oxygen, and this reaction is sped up by a manganese dioxide catalyst.
其他一些化合物也会分解。过氧化氢分解为水和氧气，二氧化锰催化剂可加快这一反应。
Hydrogen peroxide → water + oxygen.
过氧化氢 → 水 + 氧气。
9. Combustion, Respiration and Photosynthesis | 燃烧、呼吸作用与光合作用
Burning a fuel in plenty of oxygen is called complete combustion. The products are carbon dioxide and water.
燃料在充足氧气中燃烧称为完全燃烧。生成物是二氧化碳和水。
Example: methane + oxygen → carbon dioxide + water.
示例：甲烷 + 氧气 → 二氧化碳 + 水。
Respiration in cells gives out energy and produces carbon dioxide and water from glucose and oxygen.
细胞呼吸释放能量，并由葡萄糖和氧气生成二氧化碳和水。
Glucose + oxygen → carbon dioxide + water.
葡萄糖 + 氧气 → 二氧化碳 + 水。
Photosynthesis is the reverse process. Plants use light energy, carbon dioxide and water to make glucose and release oxygen.
光合作用是相反的过程。植物利用光能、二氧化碳和水制造葡萄糖并释放氧气。
Carbon dioxide + water → glucose + oxygen (light and chlorophyll needed).
二氧化碳 + 水 → 葡萄糖 + 氧气（需要光和叶绿素）。
Notice that the same substances appear on different sides of the arrow in respiration and photosynthesis. Always check the direction of the arrow before you answer.
注意呼吸作用与光合作用中相同的物质出现在箭头的不同侧。答题前务必确认箭头的方向。
10. Common Mistakes and How to Avoid Them | 常见错误与避免方法
Mistake 1: using formulas instead of names. 'H₂ + O₂ → H₂O' is a symbol equation, not a word equation.
错误 1：用化学式代替名称。"H₂ + O₂ → H₂O" 是符号方程式，不是文字方程式。
Mistake 2: putting the products on the left. The arrow must always point from reactants to products.
错误 2：把生成物写在左边。箭头必须始终由反应物指向生成物。
Mistake 3: leaving out one product. Reactions with acids often give two or three products, such as salt, water and carbon dioxide.
错误 3：漏写一种生成物。与酸的反应常常生成两种或三种产物，例如盐、水和二氧化碳。
Mistake 4: trying to balance the equation with numbers. Word equations are never balanced at KS3.
错误 4：试图用数字配平方程式。KS3 阶段文字方程式从不配平。
Mistake 5: spelling errors in chemical names, such as 'magnesium' written as 'magnisium'.
错误 5：化学名称拼写错误，例如把 "magnesium" 写成 "magnisium"。
Mistake 6: forgetting the reaction condition, such as heat or a catalyst, when the question asks for it.
错误 6：当题目要求时，忘记写出反应条件，例如加热或催化剂。
11. Exam Question Styles and Mark Scheme Tips | 考试题型与评分要点
Style 1: complete the equation. You are given one side and must fill in the missing names.
题型 1：补全方程式。题目给出其中一侧，你需填入缺失的名称。
Style 2: write the word equation from a description. For example, 'zinc reacts with dilute hydrochloric acid'.
题型 2：根据描述写文字方程式。例如"锌与稀盐酸反应"。
Style 3: name the reactants or products. You are given an equation and asked to identify each part.
题型 3：写出反应物或生成物的名称。题目给出方程式，要求你辨认各部分。
Style 4: link the equation to observations, such as bubbles, a colour change or a white solid forming.
题型 4：把方程式与实验现象联系，例如气泡、颜色变化或白色固体生成。
Mark scheme tips: one mark is usually given for the correct reactants, one for the correct products, and sometimes one for the arrow or the condition.
评分要点：通常反应物正确得 1 分，生成物正确得 1 分，有时箭头或反应条件再得 1 分。
Write the arrow clearly. If you write '→' as a dash or forget it completely, you may lose a mark even when the names are right.
箭头要写清楚。如果你把 "→" 写成一条短横线或完全漏写，即使名称正确也可能失分。
12. Practice Questions with Answers | 练习题及答案
Try each question first, then check the answer below it. Covering the answers with a sheet of paper works well.
先自己做每道题，再看下面的答案。用一张纸遮住答案效果很好。
the word equation for burning sulfur in oxygen. Answer: sulfur + oxygen → sulfur dioxide.
题 1：写出硫在氧气中燃烧的文字方程式。答案：硫 + 氧气 → 二氧化硫。
zinc reacting with sulfuric acid. Answer: zinc + sulfuric acid → zinc sulfate + hydrogen.
题 2：写出锌与硫酸反应的文字方程式。答案：锌 + 硫酸 → 硫酸锌 + 氢气。
for heating calcium carbonate. Answer: calcium carbonate → calcium oxide + carbon dioxide.
题 3：写出加热碳酸钙的文字方程式。答案：碳酸钙 → 氧化钙 + 二氧化碳。
ing with sulfuric acid. Answer: sodium hydroxide + sulfuric acid → sodium sulfate + water.
题 4：写出氢氧化钠与硫酸反应的文字方程式。答案：氢氧化钠 + 硫酸 → 硫酸钠 + 水。
cting with copper sulfate solution. Answer: iron + copper sulfate → iron sulfate + copper.
题 5：写出铁与硫酸铜溶液反应的文字方程式。答案：铁 + 硫酸铜 → 硫酸亚铁 + 铜。
Q6: Name the products when methane burns in oxygen. Answer: carbon dioxide and water.
题 6：写出甲烷在氧气中燃烧的生成物。答案：二氧化碳和水。
r the reaction between magnesium and oxygen. Answer: magnesium + oxygen → magnesium oxide.
题 7：写出镁与氧气反应的文字方程式。答案：镁 + 氧气 → 氧化镁。
en peroxide with a manganese dioxide catalyst. Answer: hydrogen peroxide → water + oxygen.
题 8：写出在二氧化锰催化下过氧化氢分解的文字方程式。答案：过氧化氢 → 水 + 氧气。
Q9: A gas turns limewater milky. Which product does this show? Answer: carbon dioxide.
题 9：一种气体使石灰水变浑浊，这说明生成了哪种物质？答案：二氧化碳。
e the word equation for photosynthesis. Answer: carbon dioxide + water → glucose + oxygen.
题 10：写出光合作用的文字方程式。答案：二氧化碳 + 水 → 葡萄糖 + 氧气。
common patterns, such as metal + acid → salt + hydrogen, appear in your mind immediately.
如果你能凭记忆答出这十道题，说明你已经准备好应对 CIE KS3 的文字方程式题目。持续练习，直到像"金属 + 酸 → 盐 + 氢气"这样的常见规律能立刻浮现在脑海中。
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