Year 8 CAIE Chemistry: Vocabulary & Terminology Quick Memorization Guide | Year 8 CAIE 化学：词汇术语速记指南

📚 Year 8 CAIE Chemistry: Vocabulary & Terminology Quick Memorization Guide | Year 8 CAIE 化学：词汇术语速记指南

Mastering the language of chemistry is half the battle won. This guide breaks down the essential Year 8 CAIE terminology into logical groups and provides simple memory hooks, root-word clues, and clear definitions to help you learn faster and retain longer.

掌握化学的语言是成功的一半。这份指南将Year 8 CAIE必学的核心术语分解为逻辑清晰的分组，并通过词根线索、联想口诀和清晰的定义，帮助你学得更快、记得更牢。

1. States of Matter & Phase Changes | 物质状态与相变

The three familiar states are solid, liquid and gas. A solid has a fixed shape and volume because its particles are packed tightly in a regular pattern.

常见的三种状态是固态、液态和气态。固体有固定的形状和体积，因为其粒子紧密且规则地排列。

Liquid means the particles are still close but can slide past each other, so a liquid takes the shape of its container but has a fixed volume.

液体的粒子仍然靠近但可以相互滑动，因此液体会呈现容器的形状，但体积固定不变。

Gas particles are far apart and move quickly in all directions, so a gas fills the whole container and has no fixed shape or volume.

气体的粒子间距很大，朝各个方向快速运动，因此气体会充满整个容器，没有固定的形状和体积。

Melting / Fusion – solid → liquid (think of ice melting)
熔化 – 固态→液态（想象冰融化）
Freezing – liquid → solid
凝固 – 液态→固态
Boiling / Vaporisation – liquid → gas throughout the liquid (bubbles form)
沸腾 / 汽化 – 整个液体内部转化为气体（产生气泡）
Evaporation – liquid → gas only at the surface, at any temperature below boiling point.
蒸发 – 仅在液体表面发生的液态→气态过程，可在低于沸点的任何温度下进行。
Condensation – gas → liquid
冷凝 – 气态→液态
Sublimation – solid → gas directly (e.g., dry ice, iodine)
升华 – 固态直接变为气态（例如干冰、碘）
Deposition – gas → solid directly (e.g., frost forming on a cold surface)
凝华 – 气态直接变为固态（例如寒冷表面上的霜）

Memory tip: For sublimation, think “sub-lime” – the solid skips the liquid stage just like a lime wedge vanishes without turning into juice.

记忆技巧：sublimation（升华），联想”跳过液(skip-liquid)”，固体跳过液态直接变成气体。

2. The Particle Model & Diffusion | 粒子模型与扩散

All matter is made of tiny, constantly moving particles. In a warmer substance, particles move faster, which is why heating speeds up processes like diffusion.

所有物质都由微小的、不断运动的粒子构成。温度升高时粒子运动加快，因此加热会加速扩散等过程。

Diffusion is the movement of particles from a region of higher concentration to a region of lower concentration, until they are evenly spread. It happens faster in gases than in liquids because gas particles move more freely.

扩散是粒子从高浓度区域向低浓度区域运动，直到均匀分布的过程。气体中的扩散比液体中快，因为气体粒子运动更自由。

Brownian motion is the random, jerky movement of visible particles (like smoke or pollen) caused by collisions with much smaller, invisible particles of liquid or gas. It provides evidence for the particle model.

布朗运动是可见微粒（如烟雾或花粉）因受到更小的、看不见的液体或气体粒子的碰撞而产生的随机、不规则的抖动。它为粒子模型提供了证据。

Root helper: “Fuse” in diffusion comes from Latin fundere “to pour”. Think of particles pouring outwards. “Brownian” is named after Robert Brown, who observed pollen grains jiggling in water.

词根助手：diffusion 中的”fuse”来自拉丁语 fundere”倾倒”，想象粒子向外倾倒。Brownian 以罗伯特·布朗命名，他观察到花粉粒在水中抖动。

3. Elements, Compounds & Mixtures | 元素、化合物与混合物

An element is a pure substance made of only one type of atom. It cannot be broken down into anything simpler by chemical reactions. Examples: oxygen (O), iron (Fe), gold (Au).

元素是由同一种原子组成的纯净物，无法通过化学反应分解成更简单的物质。例如：氧 (O)、铁 (Fe)、金 (Au)。

A compound is a pure substance formed when two or more different elements are chemically bonded together in a fixed ratio. The properties of a compound are different from the elements that form it. For instance, water (H₂O) is a liquid, while hydrogen and oxygen are gases.

化合物是由两种或多种不同元素通过化学键按固定比例结合而成的纯净物。化合物的性质不同于组成它的元素。例如水 (H₂O) 是液体，而氢和氧是气体。

A mixture consists of two or more substances (elements or compounds) that are not chemically joined. They can be separated by physical methods like filtration, distillation or chromatography. Air is a mixture of gases; salt water is a mixture of salt and water.

混合物由两种或多种未发生化学结合的物质（元素或化合物）组成，可通过过滤、蒸馏、色谱等物理方法分离。空气是气体混合物；盐水是盐和水的混合物。

Quick memory: Element = single type of atom; Compound = fixed combination; Mixture = physical blend.

快速记忆：元素 = 同种原子；化合物 = 固定组合；混合物 = 物理混杂。

4. Atomic Structure & Subatomic Particles | 原子结构与亚原子粒子

An atom is the smallest particle of an element that retains its chemical properties. It contains a central nucleus made of protons and neutrons, surrounded by electrons moving in shells.

原子是保持元素化学性质的最小粒子。它包含一个由质子和中子组成的中央原子核，以及围绕原子核在电子层中运动的电子。

Particle 粒子	Relative Charge 相对电荷	Relative Mass 相对质量	Location in Atom 位置
Proton 质子	+1	1	Nucleus 原子核
Neutron 中子	0	1	Nucleus 原子核
Electron 电子	-1	1/1836 (negligible 可忽略)	Shells around nucleus 核外电子层

An atom is electrically neutral because the number of protons equals the number of electrons. The atomic number (proton number) defines the element; the mass number is the sum of protons and neutrons.

原子呈电中性，因为质子数等于电子数。原子序数（质子数）决定了元素的种类；质量数是质子数和中子数之和。

Memory aid: Protons = Positive (both start with ‘P’). Neutrons = Neutral (both start with ‘N’). Electrons are the lightweight movers. Imagine the nucleus as a heavy football stadium with electrons as tiny bees buzzing in the outer stands.

记忆窍门：质子 (Proton) 带正电 (Positive)，都以 P 开头。中子 (Neutron) 不带电 (Neutral)，都以 N 开头。电子是轻量的运动者。把原子核想象成沉重的足球场，电子就像外场看台上嗡嗡飞舞的小蜜蜂。

5. The Periodic Table & Element Families | 周期表与元素家族

The Periodic Table arranges elements in order of increasing atomic number. Vertical columns are called groups; horizontal rows are called periods. Elements in the same group have similar chemical properties because they have the same number of electrons in their outer shell.

周期表按原子序数递增的顺序排列元素。纵列称为族；横行称为周期。同一族的元素化学性质相似，因为它们的最外层电子数相同。

Key groups to remember (Year 8 focus):

需要记牢的关键族（Year 8 重点）：

Group 1 – Alkali metals: lithium (Li), sodium (Na), potassium (K). They are soft, shiny, reactive metals that react vigorously with water to form an alkaline solution and hydrogen gas. Reactivity increases down the group.
第1族 – 碱金属：锂 (Li)、钠 (Na)、钾 (K)。它们是质地柔软、有光泽的活泼金属，与水剧烈反应生成碱性溶液和氢气。反应活性自上而下递增。
Group 7 – Halogens: fluorine (F), chlorine (Cl), bromine (Br), iodine (I). They are non-metal elements that exist as diatomic molecules (F₂, Cl₂, etc.) and become darker and less reactive down the group.
第7族 – 卤族元素（卤素）：氟 (F)、氯 (Cl)、溴 (Br)、碘 (I)。它们是非金属元素，以双原子分子 (F₂, Cl₂ 等) 形式存在，从上到下颜色逐渐加深、反应活性减弱。
Group 0/8 – Noble gases: helium (He), neon (Ne), argon (Ar). They are monatomic, colourless, unreactive gases because they have a full outer shell of electrons.
第0/8族 – 惰性气体（稀有气体）：氦 (He)、氖 (Ne)、氩 (Ar)。它们是单原子、无色、化学性质不活泼的气体，因为它们的最外层电子已满。

Word-play memory: “Alkali” sounds like “Alka-line” – these metals make an alkaline line in water. “Halogens” comes from Greek hals (salt) + gen (producer); they form salts with metals (e.g., sodium chloride). Noble gases are “noble” because they don’t mix with the common elements.

文字游戏记忆：“Alkali”听起来像“Alka-line”（碱线），这些金属遇水形成一条碱性线。“Halogens”源于希腊语 hals（盐）+ gen（产生者），它们与金属生成盐（如氯化钠）。Noble gases“贵”在不与普通元素混在一起。

6. Physical vs Chemical Changes & Reactions | 物理变化与化学变化及反应

A physical change alters the form or appearance of a substance but does not produce a new substance. Examples include melting, freezing, dissolving salt in water, and cutting paper. These changes are usually reversible.

物理变化改变物质的形式或外观，但不产生新物质。例如熔化、凝固、把盐溶于水、剪纸。这些变化通常是可逆的。

A chemical change (chemical reaction) produces one or more new substances with different properties. Signs include a colour change, temperature change, formation of gas (bubbles), formation of a precipitate (solid from two liquids), or an odour being produced. Combustion and rusting are chemical changes.

化学变化（化学反应）会产生一种或多种性质不同的新物质。迹象包括颜色变化、温度变化、气体生成（气泡）、沉淀生成（由两种液体产生固体）或有气味产生。燃烧和生锈是化学变化。

Reactants are the starting substances; products are the new substances formed. In the word equation magnesium + oxygen → magnesium oxide, magnesium and oxygen are reactants and magnesium oxide is the product.

反应物是起始物质；生成物是形成的新物质。在文字方程式镁 + 氧气 → 氧化镁中，镁和氧气是反应物，氧化镁是生成物。

Mnemonics: Think of “Chemical” as “Changes Create Entirely New Identities”. Physical = “Physique” – only appearance changes.

记忆法：把“Chemical”想成“变化创造出全新的身份 (Changes Create Entirely New Identities)”。Physical（物理的）类似体型 (Physique) – 只有外观改变。

7. Types of Chemical Reactions | 化学反应类型

Combustion is a reaction with oxygen that releases energy as heat and light. Complete combustion of a hydrocarbon fuel produces carbon dioxide and water. Incomplete combustion can produce carbon monoxide (toxic) or carbon (soot).

燃烧是与氧气发生的放出热和光的反应。碳氢燃料的完全燃烧生成二氧化碳和水。不完全燃烧会产生一氧化碳（有毒）或碳（炭黑）。

Oxidation is the gain of oxygen by a substance. The substance that provides the oxygen is the oxidising agent. When iron rusts, it gains oxygen and water forms hydrated iron(III) oxide – a slow oxidation reaction.

氧化是物质得到氧的过程。提供氧的物质是氧化剂。铁生锈时，铁与氧和水反应生成水合氧化铁 – 一种缓慢的氧化反应。

Thermal decomposition is the breakdown of a compound by heating. Example: calcium carbonate → calcium oxide + carbon dioxide. You can remember it as “heat + decomposition”.

热分解是通过加热使化合物分解。例如：碳酸钙 → 氧化钙 + 二氧化碳。可记为“加热+分解”。

Displacement reaction occurs when a more reactive element takes the place of a less reactive element in a compound. Zinc displacing copper from copper sulfate solution: zinc + copper sulfate → zinc sulfate + copper.

置换反应发生在较活泼的元素将化合物中较不活泼的元素取代出来时。锌从硫酸铜溶液中置换出铜：锌 + 硫酸铜 → 硫酸锌 + 铜。

Neutralisation is the reaction between an acid and a base to produce salt and water. acid + base → salt + water. (Covered in detail next.)

中和反应是酸和碱反应生成盐和水的过程。酸 + 碱 → 盐 + 水。（下一节详述）

Memorisation chant: Combustion needs O₂, oxidation gains O, thermal decomposition breaks by heat, displacement swaps places.

记忆口诀：Combustion 需要 O₂，Oxidation 得到 O，Thermal decomposition 加热分解，Displacement 相互置换。

8. Acids, Bases, Alkalis & the pH Scale | 酸、碱、可溶碱与pH标度

An acid is a substance that releases hydrogen ions (H⁺) in water. Common lab acids: hydrochloric acid (HCl), sulfuric acid (H₂SO₄), nitric acid (HNO₃). Acids taste sour (but never taste in a lab!), turn blue litmus red, and have pH less than 7.

酸是在水中释放氢离子 (H⁺) 的物质。常见的实验室酸：盐酸 (HCl)、硫酸 (H₂SO₄)、硝酸 (HNO₃)。酸有酸味（切勿在实验室品尝！），使蓝色石蕊试纸变红，pH 小于 7。

A base is a substance that neutralises an acid. An alkali is a soluble base that releases hydroxide ions (OH⁻) in water. Common alkalis: sodium hydroxide (NaOH), potassium hydroxide (KOH). Alkalis feel soapy, turn red litmus blue, and have pH greater than 7.

碱是能中和酸的物质。可溶碱 (alkali) 是指在水中能溶解并释放氢氧根离子 (OH⁻) 的碱。常见的可溶碱：氢氧化钠 (NaOH)、氢氧化钾 (KOH)。碱有滑腻感，使红色石蕊试纸变蓝，pH 大于 7。

The pH scale ranges from 0 to 14. 7 is neutral; 0–6 is acidic (lower = stronger acid); 8–14 is alkaline (higher = stronger alkali). Universal indicator shows a range of colours depending on pH.

pH 标度范围从 0 到 14。7 为中性；0–6 为酸性（数字越小酸性越强）；8–14 为碱性（数字越大碱性越强）。通用指示剂根据 pH 值呈现不同颜色。

A salt is the ionic compound formed when the hydrogen of an acid is replaced by a metal ion (or ammonium). For hydrochloric acid, salts are chlorides; for sulfuric acid, sulfates; for nitric acid, nitrates.

盐是酸中的氢被金属离子（或铵根）取代后形成的离子化合物。盐酸产生氯化物盐；硫酸产生硫酸盐；硝酸产生硝酸盐。

Memory: “Acid on blue litmus = Red” – think of a warning sign; “Alkali on red = Blue” – think of the sky getting bluer. Neutralisation: acid + base → “salt water” (salt + water) – easily remembered as “salt water”.

记忆：“酸遇蓝石蕊变红”——想象成警告标志；“碱遇红石蕊变蓝”——想象天空更蓝。中和反应：酸 + 碱 → “盐水”（盐 + 水）——轻松记为“salt water”。

9. Separation Techniques & Lab Terminology | 分离技术与实验室术语

Filtration separates an insoluble solid from a liquid using filter paper. The solid trapped is the residue; the liquid that passes through is the filtrate.

过滤用滤纸从液体中分离出不溶性固体。被截留的固体称为滤渣；穿过滤纸的液体称为滤液。

Evaporation & Crystallisation: evaporation quickly obtains the dissolved solid from a solution by heating, but can decompose some salts. Crystallisation is slower – the solution is gently heated to form a saturated solution, then cooled to form crystals.

蒸发与结晶：蒸发通过加热从溶液中快速得到溶解的固体，但可能使某些盐分解。结晶较慢——将溶液微热浓缩成饱和溶液，再冷却形成晶体。

Distillation: simple distillation separates a solvent from a solution by boiling the mixture and condensing the vapour. The pure liquid collected is the distillate. Fractional distillation separates two or more miscible liquids with different boiling points using a fractionating column.

蒸馏：简单蒸馏通过煮沸混合物并冷凝蒸汽来分离溶剂和溶液。收集到的纯净液体称为馏出液。分馏使用分馏柱分离两种或多种沸点不同的互溶液体。

Chromatography separates small amounts of dissolved substances based on their different solubilities. A solvent moves up the paper carrying components at different speeds. The more soluble a substance, the further it travels.

色谱法（层析）根据溶解度的差异分离少量已溶解的物质。溶剂沿滤纸上升，以不同速度携带各组分。物质的溶解度越大，移动距离越远。

Useful labware names: beaker (容器), conical flask (锥形瓶), measuring cylinder (量筒), pipette (移液管), burette (滴定管), test tube (试管), tripod (三脚架), Bunsen burner (本生灯), evaporating dish (蒸发皿).

常用实验器材名称：beaker (烧杯), conical flask (锥形瓶), measuring cylinder (量筒), pipette (移液管), burette (滴定管), test tube (试管), tripod (三脚架), Bunsen burner (本生灯), evaporating dish (蒸发皿)。

Root tip: “Chromatography” – chroma means colour (originally used for plant pigments). “Filtrate” and “filtrum” relate to a felt used to strain liquids.

词根提示：“Chromatography”中 chroma 意为颜色（最初用于植物色素）。“Filtrate”和 filrum 与用来过滤液体的毛毡有关。

10. Energy Changes in Reactions & Reaction Rate | 反应中的能量变化与反应速率

Exothermic reactions release energy to the surroundings, usually as heat, causing an increase in temperature. Examples: combustion, neutralisation, respiration. The container feels warmer.

放热反应向环境释放能量（通常为热能），导致温度升高。例如：燃烧、中和反应、呼吸作用。容器摸起来变热。

Endothermic reactions absorb energy from the surroundings, causing a temperature decrease. Examples: photosynthesis, dissolving ammonium nitrate in water. The container feels cooler.

吸热反应从环境中吸收能量，导致温度下降。例如：光合作用、将硝酸铵溶于水。容器摸起来变冷。

Memory: “Exit” = exothermic, energy exits. “En” = endothermic, energy enters.

记忆：“Exit”（出去）→ exothermic，能量出去。“En”（进入）→ endothermic，能量进入。

The rate of reaction is the speed at which reactants are used up or products are formed. It can be increased by:

反应速率是反应物消耗或生成物形成的快慢。可通过以下方法提高：

Increasing temperature (particles move faster, collide more often and with more energy)
升高温度（粒子运动更快，碰撞更频繁且能量更高）
Increasing concentration of a solution or pressure of a gas (more particles in the same space, so more collisions)
增大溶液的浓度或气体的压强（同空间内更多粒子，碰撞更多）
Increasing surface area of a solid (breaking into smaller pieces exposes more reactant particles)
增大固体的表面积（分成小块暴露出更多反应粒子）
Using a catalyst (a substance that speeds up the reaction without being chemically changed itself).
使用催化剂（一种能加快反应速率而自身化学性质不变的物质）。

A quick analogy: Imagine a dance floor – higher temperature = faster music and more energetic dancers; higher concentration = more dancers in the same space; larger surface area = more entrances for dancers to meet.

快速类比：想象一个舞池 – 升高温度 = 音乐更快，舞者更有活力；增大浓度 = 同个空间里更多舞者；增大表面积 = 更多入口供舞者相遇。

11. Word Equations & Chemical Formulae Basics | 文字方程式与化学式基础

A word equation shows the names of reactants and products, linked by an arrow (→) meaning ‘reacts to form’. Example: methane + oxygen → carbon dioxide + water.

文字方程式用物质名称表示反应物和生成物，箭头 (→) 表示“反应生成”。例如：甲烷 + 氧气 → 二氧化碳 + 水。

Chemical symbols represent elements; chemical formulae show the types and ratios of atoms in a compound. A subscript number indicates how many atoms of that element are present. E.g., H₂O: 2 hydrogen atoms, 1 oxygen atom; CO₂: 1 carbon, 2 oxygens.

化学符号代表元素；化学式表示化合物中原子的种类和原子数比例。下标数字表示该元素的原子个数。例如 H₂O：2 个氢原子，1 个氧原子；CO₂：1 个碳原子，2 个氧原子。

Some compounds have radicals (groups of atoms acting as a single charged unit), like hydroxide OH⁻, sulfate SO₄²⁻, nitrate NO₃⁻, carbonate CO₃²⁻. When writing formulae with radicals, use brackets if more than one radical is needed, e.g., Ca(OH)₂.

一些化合物含有原子团（根），即作为一个带电单元的一组原子，如氢氧根 OH⁻、硫酸根 SO₄²⁻、硝酸根 NO₃⁻、碳酸根 CO₃²⁻。写化学式时，若需要多个原子团，需使用括号，如 Ca(OH)₂。

Learning tip: Practise translating word equations into simple formula equations: sodium + chlorine → sodium chloride becomes Na + Cl₂ → NaCl (balanced later). For Year 8, focus on naming salts correctly: hydrochloric acid → chloride, sulfuric acid → sulfate, nitric acid → nitrate.

学习技巧：练习将文字方程式转化为简单的符号方程式：钠 + 氯 → 氯化钠变为 Na + Cl₂ → NaCl（暂不考虑配平）。Year 8 阶段重点掌握正确命名盐类：盐酸 → 氯化某，硫酸 → 硫酸某，硝酸 → 硝酸某。

12. Common Exam Words Decoded | 考试指令词解码

CAIE exam questions often use specific command words. Knowing what they ask for saves time and helps you pick up marks.

CAIE 考试题目常使用特定的指令词。理解它们的要求能节省时间并帮你得分。

State / Name / Give – recall a fact, word or short phrase. No explanation needed.
State / Name / Give（陈述/命名/给出） – 回想一个事实、单词或短语，无需解释。
Describe – say what happens or what you see, step by step, without giving reasons.
Describe（描述） – 讲述发生什么或看到什么，按步骤说明，不解释原因。
Explain – give reasons, using scientific ideas (such as particle theory or energy changes).
Explain（解释） – 运用科学概念（如粒子理论或能量变化）给出理由。
Compare – note similarities and differences. Often use “whereas” or “both”.
Compare（比较） – 指出相同点和不同点。常用“而”、“二者都”。
Calculate / Determine – work out a numerical answer, showing your working.
Calculate / Determine（计算/测定） – 算出数值答案，写清楚计算过程。
Predict – use patterns or data to suggest what will happen, often with a reason.
Predict（预测） – 利用规律或数据推测将会发生什么，通常要写出理由。
Suggest – think of a possible reason or interpretation when you are not told the exact answer.
Suggest（建议/提出） – 在没有确切答案的情况下，给出一个可能的原因或解释。

Top tip: Underline the command word in the question and note how many marks are given – one mark per point or step.

高分技巧：在读题时圈出指令词，并注意分值——通常每一点或每一步得一分。

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Year 8 CAIE Chemistry: Vocabulary & Terminology Quick Memorization Guide | Year 8 CAIE 化学：词汇术语速记指南