📚 Year 8 Cambridge Chemistry: Vocabulary & Terminology Quick-Reference Guide | Year 8 Cambridge 化学：词汇术语速记指南
Building a strong chemistry vocabulary is the key to understanding experiments, equations and results. This guide covers the essential terms you will meet in Year 8 Cambridge Chemistry, with clear explanations in both English and Chinese. It is designed to help you remember tricky words and use them confidently in tests and practical work.
掌握化学词汇是理解实验、方程式和结果的关键。这份指南涵盖你在 Year 8 Cambridge 化学课程中会遇到的必学术语，并提供清晰的中英文解释。它专为帮助你在考试和实验中自信地使用这些词汇而设计。
1. States of Matter | 物质的三态
All substances are made of tiny particles. The way these particles are arranged and move determines whether the substance is a solid, a liquid or a gas.
所有物质都由微小粒子构成。粒子的排列方式和运动方式决定了物质是固体、液体还是气体。
Solid – Fixed shape, fixed volume, particles packed closely in a regular pattern and only vibrating in place.
固体 – 形状固定，体积固定，粒子紧密排列成规则图案，只能原地振动。
Liquid – Takes the shape of its container, fixed volume, particles close together but can slide past each other.
液体 – 形状随容器而变，体积固定，粒子彼此靠近但可以相互滑动。
Gas – No fixed shape or volume, particles widely spread and moving rapidly in all directions.
气体 – 无固定形状和体积，粒子分散，在各个方向上快速运动。
2. Changes of State | 物态变化
Changing temperature can make a substance change its state. These physical changes are reversible and do not produce new substances.
温度变化可以使物质改变状态。这些物理变化是可逆的，不会产生新物质。
| Change | From → To | 中文 |
|---|---|---|
| Melting | Solid → Liquid | 熔化 |
| Freezing | Liquid → Solid | 凝固 |
| Boiling / Evaporation | Liquid → Gas | 沸腾 / 蒸发 |
| Condensation | Gas → Liquid | 冷凝 |
| Sublimation | Solid → Gas (no liquid stage) | 升华 |
| Deposition | Gas → Solid (no liquid stage) | 凝华 |
The melting point is the temperature at which a solid turns into a liquid; the boiling point is the temperature at which a liquid turns into a gas.
熔点是固体变为液体的温度；沸点是液体变为气体的温度。
3. Atoms, Elements, Compounds and Mixtures | 原子、元素、化合物与混合物
Everything in chemistry builds up from atoms. It is extremely important not to confuse these four terms.
化学中的一切都是由原子构成的。这四种术语绝对不能混淆。
Atom – The smallest particle of an element that can take part in a chemical reaction.
原子 – 能参与化学反应的元素最小粒子。
Element – A pure substance made of only one type of atom. It cannot be broken down into simpler substances by chemical means.
元素 – 由同一种原子组成的纯净物，不能用化学方法分解成更简单的物质。
Compound – A pure substance made of two or more different types of atoms chemically bonded together in a fixed ratio.
化合物 – 由两种或两种以上不同原子以固定比例通过化学键结合而成的纯净物。
Mixture – Two or more substances (elements or compounds) that are physically mixed but not chemically joined. They can be separated easily.
混合物 – 两种或两种以上物质（元素或化合物）物理混合在一起，没有化学结合，容易被分离。
4. The Periodic Table and Symbols | 周期表与元素符号
The Periodic Table lists all known elements in order of increasing atomic number. Each element has a unique chemical symbol, usually one or two letters.
元素周期表按原子序数递增的顺序排列所有已知元素。每种元素都有一个独特的化学符号，通常为一或两个字母。
- Hydrogen – H (the lightest element) / 氢（最轻的元素）
- Oxygen – O (essential for combustion) / 氧（燃烧必需）
- Carbon – C (found in all living things) / 碳（所有生物中都含有）
- Iron – Fe (from Latin 'ferrum') / 铁（符号源自拉丁文）
- Copper – Cu (from Latin 'cuprum') / 铜（符号源自拉丁文）
- Sodium – Na (from Latin 'natrium') / 钠（符号源自拉丁文）
Remember: The first letter of a chemical symbol is always capitalised, and the second letter, if present, is always lowercase.
请记住：元素符号的第一个字母始终大写，如果有第二个字母，则一定小写。
5. Properties of Metals and Non-metals | 金属与非金属的性质
Elements can be broadly divided into metals and non-metals. Their physical and chemical properties are almost opposite.
元素可以大致分为金属和非金属。它们的物理性质和化学性质几乎完全相反。
Metals are usually shiny, good conductors of heat and electricity, malleable (can be beaten into sheets) and ductile (can be drawn into wires). Most are solid at room temperature (except mercury).
金属 通常有光泽，是热和电的良导体，具有延展性（可锤打成薄片）和延性（可拉成丝线）。大多数在室温下是固体（汞除外）。
Non-metals are often dull, poor conductors (insulators), brittle when solid, and have lower melting and boiling points. Many are gases at room temperature.
非金属 通常暗淡无光，是热和电的不良导体（绝缘体），固体时易碎，熔点和沸点较低。许多在室温下是气体。
Metals form positive ions, while non-metals tend to form negative ions or share electrons in reactions.
金属形成阳离子，而非金属在反应中倾向于形成阴离子或共用电子。
6. Chemical Reactions and Equations | 化学反应与方程式
A chemical reaction happens when new substances are made. Reactants turn into products, and the process is shown by a word equation or a symbol equation.
当生成新物质时就发生了化学反应。反应物转变为生成物，这一过程用文字方程式或符号方程式表示。
Reactant – A substance you start with in a reaction. / 反应物 – 反应开始时存在的物质。
Product – A substance formed in the reaction. / 生成物 – 反应中生成的物质。
A simple word equation format: sodium + water → sodium hydroxide + hydrogen
一个简单的文字方程式格式：钠 + 水 → 氢氧化钠 + 氢气
Signs of a chemical reaction include colour change, fizzing (gas production), temperature change and formation of a precipitate (solid from two liquids).
化学反应的标志包括颜色变化、冒气泡（产生气体）、温度变化以及生成沉淀（两种液体混合产生固体）。
7. Acids, Alkalis and Indicators | 酸、碱与指示剂
Acids and alkalis are common in the lab and at home. Indicators help us test whether a solution is acidic or alkaline.
酸和碱在实验室和家庭中都很常见。指示剂帮助我们检测溶液是酸性还是碱性。
Acid – A substance that releases hydrogen ions (H⁺) in water. It tastes sour and turns blue litmus paper red. Examples: hydrochloric acid (HCl), sulfuric acid (H₂SO₄), citric acid.
酸 – 在水中释放氢离子（H⁺）的物质。有酸味，能使蓝色石蕊试纸变红。例如：盐酸（HCl）、硫酸（H₂SO₄）、柠檬酸。
Alkali – A soluble base that releases hydroxide ions (OH⁻) in water. It feels soapy and turns red litmus paper blue. Examples: sodium hydroxide (NaOH), potassium hydroxide (KOH).
碱 – 可溶性的碱，在水中释放氢氧根离子（OH⁻）。手感滑腻，能使红色石蕊试纸变蓝。例如：氢氧化钠（NaOH）、氢氧化钾（KOH）。
Indicator – A substance that changes colour depending on pH. Litmus, universal indicator and red cabbage juice are common examples.
指示剂 – 随pH值而变色的物质。石蕊、通用指示剂和红甘蓝汁是常见例子。
8. pH Scale and Neutralization | pH 值与中和反应
The pH scale measures how acidic or alkaline a solution is. It ranges from 0 to 14.
pH 标度用于衡量溶液的酸碱度，范围从 0 到 14。
- pH less than 7: acidic / 酸性
- pH exactly 7: neutral / 中性 (纯水 pure water)
- pH greater than 7: alkaline / 碱性
Neutralization is the reaction between an acid and an alkali (or base) to form a salt and water. The equation is: acid + alkali → salt + water
中和反应 是酸与碱（或碱性物质）反应生成盐和水。通式为：酸 + 碱 → 盐 + 水
For example: hydrochloric acid + sodium hydroxide → sodium chloride + water (HCl + NaOH → NaCl + H₂O)
例如：盐酸 + 氢氧化钠 → 氯化钠 + 水（HCl + NaOH → NaCl + H₂O）
9. Separation Techniques | 分离技术
Mixtures can be separated using physical methods. Choosing the correct method depends on the components of the mixture.
混合物可以通过物理方法进行分离。选择正确的方法取决于混合物的成分。
| Technique | Separates | 中文 |
|---|---|---|
| Filtration | Insoluble solid from a liquid | 过滤 |
| Evaporation | Soluble solid from a solution (heat to dryness) | 蒸发 |
| Crystallisation | Soluble solid from a solution (gentle heating) | 结晶 |
| Simple Distillation | Solvent from a solution (liquid-liquid) | 简单蒸馏 |
| Fractional Distillation | Miscible liquids with different boiling points | 分馏 |
| Chromatography | Coloured substances dissolved in a solvent | 色谱法 |
When describing separation diagrams in exams, always name the apparatus (e.g. filter funnel, condenser, beaker) and the property being used (e.g. particle size, boiling point).
在考试中描述分离装置图时，一定要说出仪器名称（如漏斗、冷凝管、烧杯）和所利用的性质（如粒径、沸点）。
10. Key Verbs in Chemistry | 化学常用动词
Command words in questions tell you exactly what to do. Misunderstanding them can lose you marks.
题目中的指令词明确告诉你要做什么，理解错误会失分。
Describe: Say what you see or what happens, without explaining why. / 描述：说出你看到或发生了什么，不要解释原因。
Explain: Give reasons why something happens. Always use 'because'. / 解释：给出某事发生的原因，必须用到“因为”。
Compare: Point out similarities and differences. / 比较：指出相同点和不同点。
Evaluate: Look at advantages and disadvantages and make a judgement. / 评价：分析优点和缺点并做出判断。
Predict: Suggest what will happen based on evidence or a pattern. / 预测：根据证据或规律推测会发生什么。
Calculate: Work out a numerical answer, showing your steps. / 计算：求出数值答案，并展示解题步骤。
11. Hazards and Safety Symbols | 危险品与安全标志
You must be able to recognise hazard symbols in the lab. They warn you about risks of chemicals and equipment.
你必须能在实验室认出危险标志。它们提醒你化学品和设备的潜在风险。
- Flammable – catches fire easily / 易燃 – 容易着火
- Corrosive – damages skin, eyes and metals / 腐蚀性 – 会损伤皮肤、眼睛和金属
- Toxic – poisonous if swallowed or inhaled / 有毒 – 吞食或吸入会中毒
- Oxidising – provides oxygen to make other substances burn more fiercely / 助燃 – 提供氧气使其他物质燃烧更剧烈
- Harmful/Irritant – can cause skin irritation or harm if not handled carefully / 有害/刺激性 – 可能引起皮肤刺激，不小心处理会有害
Always wear safety goggles and a lab coat. Know the location of the fire extinguisher, first aid kit and emergency exit.
始终佩戴护目镜和实验服。知道灭火器、急救箱和紧急出口的位置。
12. Prefixes and Quantitative Terms | 前缀与数量术语
In chemistry, prefixes help you understand numbers of atoms or measure quantities. These appear in names and equations.
在化学中，前缀有助于你理解原子数目或测量数量。它们会出现在名称和方程式中。
- Mono- (1), di- (2), tri- (3), tetra- (4) – used in naming compounds (e.g. carbon dioxide CO₂, phosphorus trichloride PCl₃).
- Mono- (1)、di- (2)、tri- (3)、tetra- (4) – 用于命名化合物（如二氧化碳 CO₂，三氯化磷 PCl₃）。
- Mass, volume, concentration – mass is measured in grams (g); volume in cm³ or dm³; concentration is the amount of solute per unit volume of solution.
- 质量、体积、浓度 – 质量以克（g）为单位；体积以 cm³ 或 dm³ 为单位；浓度是单位体积溶液中溶质的量。
- Solute, solvent, solution – solute dissolves in solvent to make a solution. / 溶质、溶剂、溶液 – 溶质溶解在溶剂中形成溶液。
Practise drawing particle diagrams to show the difference between dilute and concentrated solutions: more solute particles in the same volume means higher concentration.
练习画粒子图来表示稀溶液和浓溶液的区别：相同体积内溶质粒子越多，浓度越高。
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