📚 Year 9 CCEA Chemistry: Key Terms Quick Revision Guide | CCEA Year 9 化学：核心词汇速记指南
Mastering the specific vocabulary of chemistry is the first and most important step toward success in your Year 9 CCEA Science exam. This guide is designed to help you quickly learn, understand and recall the essential chemistry terms you will meet in class, in your textbook and in test questions. We have grouped the words into ten clear sections, each with a simple English explanation immediately followed by a Chinese translation. Use this page to revise, test yourself and build your confidence with scientific language.
掌握化学学科中的专门词汇，是你在Year 9 CCEA科学考试中取得好成绩的第一步，也是最重要的一步。这份指南旨在帮助你快速学习、理解并牢记在课堂、教材和试题中会遇到的化学核心术语。我们将词汇分为十个清晰的板块，每个术语都配有简明的英文解释，并紧随其后附上对应的中文翻译。使用本页内容进行复习、自我测试，在白话科学语言中建立信心。
1. Fundamentals of Chemistry: Matter and Particles | 化学基础：物质与粒子
Matter is anything that has mass and takes up space (volume). All the 'stuff' around you — air, water, iron, plastic — is matter.
物质是任何具有质量并占据空间（体积）的东西。你周围所有的“东西”——空气、水、铁、塑料——都是物质。
A substance is a type of matter with a fixed composition and specific properties. Chemistry often distinguishes between pure substances and mixtures.
一种具有固定组成和特定性质的材料被称为物质。化学中常区分纯净物与混合物。
Atoms are the smallest neutral particles of an element that can take part in a chemical reaction. An atom of gold is still gold, no matter how many times you cut it (in theory).
原子是元素中能够参加化学反应的最小中性粒子。理论上，一个金原子无论如何被切割，它仍然是金。
Molecules are groups of two or more atoms chemically bonded together. They can be elements (like O₂) or compounds (like H₂O).
分子是由两个或两个以上原子通过化学键结合在一起的粒子团。它们可以是单质分子（如O₂），也可以是化合物分子（如H₂O）。
An element is a pure substance made of only one type of atom. All elements are listed on the Periodic Table, for example carbon (C) and oxygen (O).
元素是由同一种原子组成的纯净物。所有元素都列在元素周期表中，例如碳（C）和氧（O）。
A compound is a pure substance made of two or more different types of atom chemically combined in fixed proportions. Water (H₂O) and carbon dioxide (CO₂) are compounds.
化合物是由两种或两种以上不同种类的原子通过化学方式以固定比例结合而成的纯净物。水（H₂O）和二氧化碳（CO₂）都是化合物。
A mixture consists of two or more substances (elements or compounds) that are physically mixed but not chemically combined. Air is a mixture of nitrogen, oxygen and other gases.
混合物由两种或更多物质（元素或化合物）物理混合而成，它们之间没有发生化学结合。空气就是氮气、氧气和其他气体的混合物。
A physical change alters the form or appearance of a substance but not its chemical identity. Melting ice into water is a physical change.
物理变化改变物质的形式或外观，但不改变其化学身份。冰融化成水就是一种物理变化。
A chemical change produces new substances with different properties from the starting materials. Burning wood or rusting iron are chemical changes.
化学变化产生性质不同于初始物质的新的物质。燃烧木材或铁生锈都是化学变化。
2. Atomic Structure and Key Terms | 原子结构与核心术语
Atoms contain a tiny, dense nucleus at the centre, which holds positively charged protons and neutral neutrons. Almost the entire mass of an atom is concentrated in the nucleus.
原子中心有一个微小而致密的原子核，其中含有带正电的质子和不带电的中子。原子的几乎全部质量都集中在原子核上。
Protons are sub-atomic particles with a relative charge of +1 and a relative mass of 1. The number of protons defines the element: this is the atomic number.
质子是相对电荷为+1、相对质量为1的亚原子粒子。质子的数目决定了元素的种类，这个数目称为原子序数。
Neutrons have no electric charge (neutral) and a relative mass of 1. They help to hold the nucleus together and add to the mass number.
中子不带电荷（中性），相对质量为1。它们帮助维持原子核的稳定，并贡献质量数。
Electrons are tiny, negatively charged particles (charge −1) that orbit the nucleus in energy levels or shells. Their mass is almost negligible compared to protons and neutrons.
电子是微小的、带负电荷的粒子（电荷为−1），它们在电子层或电子壳中绕原子核运动。电子的质量与质子和中子相比几乎可以忽略不计。
The mass number (or nucleon number) is the total number of protons and neutrons in the nucleus. An atom can be represented as: mass number above, atomic number below, followed by the symbol.
质量数（或称核子数）是原子核中质子数与中子数的总和。一个原子可以表示为：质量数在上，原子序数在下，后跟元素符号。
An ion is a charged particle formed when an atom, or group of atoms, loses or gains electrons. Losing electrons makes a positive ion (cation); gaining electrons makes a negative ion (anion).
离子是原子或原子团因失去或获得电子而形成的带电粒子。失去电子形成阳离子；得到电子形成阴离子。
Electron shells (or energy levels) are arranged around the nucleus. The first shell can hold up to 2 electrons, the second up to 8, and the third also up to 8 (at Year 9 level). The way electrons are arranged determines how the element reacts.
电子层（或能级）围绕原子核排列。第一层最多容纳2个电子，第二层最多8个，第三层也是最多8个（在Year 9阶段）。电子的排布方式决定了元素的化学性质。
3. Elements, Compounds and Mixtures – Quick Distinctions | 单质、化合物和混合物 – 快速辨析
A pure substance has a fixed, unchanging composition and sharp melting and boiling points. Pure water boils at exactly 100 °C at standard pressure.
纯净物具有固定不变的组成以及明确的熔点和沸点。在标准气压下，纯水恰好在100 °C沸腾。
An element cannot be broken down into simpler substances by chemical means. Iron (Fe), sulfur (S) and chlorine (Cl₂) are all elements.
元素不能通过化学方法被分解成更简单的物质。铁（Fe）、硫（S）和氯气（Cl₂）都是元素。
Compounds have properties that are completely different from the elements they are made from. Sodium is a reactive metal; chlorine is a toxic gas, but sodium chloride is safe table salt.
化合物的性质与组成它们的元素的性质完全不同。钠是一种活泼金属，氯是有毒气体，但氯化钠是可安全食用的食盐。
In a mixture, each component keeps its own properties. Mixtures can be separated by physical techniques like filtration or distillation because there is no chemical bond between the parts.
在混合物中，每一种组分都保持其自身的性质。混合物可通过过滤或蒸馏等物理方法分离，因为各组分之间不存在化学键。
An alloy is a mixture of a metal with other elements, usually other metals. Steel is an alloy of iron and carbon. Alloys often have more useful properties than pure metals.
合金是金属与其他元素（通常为其他金属）的混合物。钢是铁和碳的合金。合金通常比纯金属具有更实用的性质。
4. The Periodic Table Unpacked | 元素周期表解析
The Periodic Table arranges all known elements in order of increasing atomic number. The vertical columns are called groups; the horizontal rows are called periods.
元素周期表按照原子序数递增的顺序排列所有已知元素。纵列称为族，横行称为周期。
Elements in the same group have the same number of electrons in their outermost shell and therefore similar chemical properties. Group 1 elements are all very reactive metals.
同一族的元素最外层电子数相同，因此具有相似的化学性质。第I族元素都是非常活泼的金属。
Group 1 are the alkali metals: they are soft, shiny when freshly cut, and react violently with water producing an alkaline solution and hydrogen gas.
第I族是碱金属：它们质地柔软，刚切开时有光泽，与水剧烈反应生成碱性溶液和氢气。
Group 7 are the halogens: very reactive non‑metals that exist as diatomic molecules, e.g., F₂, Cl₂. Halogens can form salts when they react with metals.
第VII族是卤素：非常活泼的非金属，以双原子分子形式存在，如F₂、Cl₂。卤素与金属反应会生成盐。
Group 0 (or Group 8) are the noble gases: helium, neon, argon, etc. They have full outer shells and are extremely unreactive.
第0族（或第VIII族）是稀有气体：氦、氖、氩等。它们具有满电子外层，因此极其不活泼。
Metals are found on the left and centre of the table; they are generally shiny, conduct electricity and heat, and are malleable. Non‑metals are on the right, mostly gases or brittle solids.
金属位于周期表的左侧和中部，通常有光泽、导电导热、具有延展性。非金属位于右侧，多为气体或脆性固体。
5. Chemical Reactions and Equations | 化学反应与化学方程式
A chemical reaction is a process in which one or more substances, the reactants, are converted into one or more different substances, the products.
化学反应是一种过程，在这个过程中一种或多种物质（反应物）转变为一种或多种不同的物质（生成物）。
actants and products to describe a reaction. Example: magnesium + oxygen → magnesium oxide
文字表达式用反应物和生成物的名称来描述一个反应。例如：镁 + 氧气 → 氧化镁
A symbol equation uses chemical symbols and formulas to show the reaction. To follow the law of conservation of mass, symbol equations must be balanced.
符号方程式用化学符号和化学式来表示反应。为了遵循质量守恒定律，符号方程式必须配平。
The law of conservation of mass states that atoms are not created or destroyed in a chemical reaction, only rearranged. The total mass of reactants equals the total mass of products.
质量守恒定律指出，在化学反应中原子既不会被创造也不会被消灭，只是重新排列。反应物的总质量等于生成物的总质量。
State symbols are often added in brackets after each formula: (s) for solid, (l) for liquid, (g) for gas and (aq) for aqueous (dissolved in water).
状态符号常被写在每个化学式的括号中：（s）表示固体，（l）表示液体，（g）表示气体，（aq）表示溶液（溶于水）。
A precipitate is an insoluble solid that forms when two solutions are mixed together. For example, mixing lead nitrate and potassium iodide solutions produces a yellow precipitate of lead iodide.
沉淀是两种溶液混合时生成的不溶性固体。例如混合硝酸铅溶液和碘化钾溶液会产生黄色的碘化铅沉淀。
A catalyst is a substance that speeds up a chemical reaction without being used up itself. Enzymes are biological catalysts; manganese dioxide can catalyse the decomposition of hydrogen peroxide.
催化剂是一种能加快化学反应速率而自身在反应中不被消耗的物质。酶是生物催化剂；二氧化锰可以催化过氧化氢的分解。
6. Acids, Bases and the pH Scale | 酸、碱与pH标度
An acid is a substance that releases hydrogen ions (H⁺) when dissolved in water. Common lab acids include hydrochloric acid (HCl), sulfuric acid (H₂SO₄) and nitric acid (HNO₃).
酸是一种溶于水时会释放氢离子（H⁺）的物质。常见的实验室酸包括盐酸（HCl）、硫酸（H₂SO₄）和硝酸（HNO₃）。
A base is a substance that can neutralise an acid. Alkalis are bases that dissolve in water to produce hydroxide ions (OH⁻). Sodium hydroxide (NaOH) is a common alkali.
碱是能够中和酸的物质。碱如果溶于水产生氢氧根离子（OH⁻），就称为可溶性碱（alkali）。常见的可溶性碱有氢氧化钠（NaOH）。
en an acid and a base to produce a salt and water. In general: acid + base → salt + water.
中和是酸与碱反应生成盐和水的过程。通式为：酸 + 碱 → 盐 + 水。
The pH scale measures how acidic or alkaline a solution is. It runs from 0 (very acidic) to 14 (very alkaline), with 7 being neutral (pure water).
pH标度用于衡量溶液的酸碱程度。范围从0（强酸性）到14（强碱性），7为中性（纯水）。
Indicators are substances that change colour depending on the pH. Litmus paper turns red in acid and blue in alkali. Universal indicator changes through a range of colours, from red in strong acid to purple in strong alkali.
指示剂是根据pH值改变颜色的物质。石蕊试纸遇酸变红，遇碱变蓝。通用指示剂会随着pH值变化呈现从强酸性时的红色到强碱性时的紫色的完整色谱。
A salt is the metal compound formed when the hydrogen of an acid is replaced by a metal. The salt of hydrochloric acid is a chloride; the salt of sulfuric acid is a sulfate.
盐是酸中的氢被金属取代后生成的金属化合物。盐酸对应的盐是氯化物；硫酸对应的盐是硫酸盐。
7. Separating Techniques in the Lab | 实验室中的分离技术
Filtration is used to separate an insoluble solid from a liquid. The solid left on the filter paper is called the residue; the liquid that passes through is the filtrate.
过滤用于将不溶性固体从液体中分离出来。留在滤纸上的固体称为残渣；通过滤纸的液体称为滤液。
Evaporation is a method to separate a soluble solid from a solution by evaporating the solvent. The solid remains as crystals, but this method may not preserve the crystalline shape perfectly.
蒸发是一种通过蒸发溶剂从溶液中分离可溶性固体的方法。固体以结晶状残留，但该方法可能无法完美地保存晶体形状。
Crystallisation is a gentler technique than simple evaporation. The solution is heated to evaporate some solvent, then allowed to cool slowly, forming large, well‑shaped crystals.
结晶是一种比简单蒸发更温和的技术。将溶液加热蒸发一部分溶剂，然后让其慢慢冷却，形成大颗粒、形状良好的晶体。
Distillation separates a solvent from a solution, or separates two liquids with different boiling points. In simple distillation, the liquid with the lower boiling point evaporates first, then condenses back into a liquid and is collected as the distillate.
蒸馏用于将溶剂从溶液中分离，或分离两种沸点不同的液体。在简单蒸馏中，沸点较低的液体首先蒸发，然后冷凝回液态，作为馏出液被收集。
Chromatography is a technique used to separate mixtures of coloured substances, such as inks or food dyes. The different components spread up the paper at different rates.
色谱法是一种用于分离混合物中有色物质（如墨水或食用色素）的技术。不同组分在纸上以不同的速率向上扩散。
Key terms: a solute is the solid that dissolves; a solvent is the liquid that does the dissolving; the resulting mixture is called a solution. Soluble means 'can dissolve'; insoluble means 'cannot dissolve'.
关键术语：溶质是溶解的固体；溶剂是进行溶解的液体；形成的混合物称为溶液。可溶表示“能够溶解”；不溶表示“不能溶解”。
8. Energy Changes in Chemical Reactions | 化学反应中的能量变化
An exothermic reaction releases energy to the surroundings, usually as heat. The temperature of the surroundings rises. Combustion and neutralisation are exothermic.
放热反应向周围环境释放能量，通常以热能的形式。周围环境温度升高。燃烧和中和反应都是放热反应。
An endothermic reaction takes in energy from the surroundings, usually as heat. The temperature of the surroundings drops. Thermal decomposition and photosynthesis are endothermic processes.
吸热反应从周围环境吸收能量，通常以热能的形式。周围环境温度下降。热分解和光合作用都是吸热过程。
Activation energy is the minimum energy that reacting particles must have for a reaction to occur. Catalysts lower the activation energy, making the reaction faster without being consumed.
活化能是反应粒子为了发生反应所必须具备的最低能量。催化剂可以降低活化能，从而加速反应而自身不被消耗。
The overall energy change in a reaction is the difference between the energy needed to break bonds in the reactants and the energy released when new bonds form in the products. Bond breaking is endothermic; bond making is exothermic.
反应的总能量变化等于断裂反应物中的化学键所需能量与生成物中新化学键形成时释放的能量之间的差值。断键吸热，成键放热。
A reaction profile is a simple graph that shows the energy of reactants and products and the activation energy 'hill'. The shape tells you if a reaction is exothermic or endothermic.
反应曲线图是显示反应物和生成物能量以及活化能“小山”的简单图像。曲线的形状能告诉你反应是放热还是吸热。
9. Essential Laboratory Vocabulary | 实验室基本词汇
A beaker is a wide glass container used for mixing, heating and stirring liquids. It is often used alongside a conical flask, which has a narrow neck to prevent splashes during swirling.
烧杯是一种宽口的玻璃容器，用于混合、加热和搅拌液体。它常与锥形瓶（圆锥瓶）配合使用，后者有细颈，用于在摇动时防止液体飞溅。
A test tube is a small glass tube used to hold small amounts of chemicals for observation or heating. A boiling tube is a larger, thicker‑walled version that can be heated directly.
试管是一种小型玻璃管，用于盛放少量化学试剂以便观察或加热。沸腾管是一种更大、壁更厚的试管，可以直接加热。
A Bunsen burner provides a single, hot flame. The safety flame (yellow) is visible, while the blue 'roaring' flame is hotter and used for intense heating.
本生灯提供单一的炽热火焰。安全火焰（黄色）可见度高，而蓝色的“强火”温度更高，用于需要强力加热的场合。
A pipette is used to measure and transfer a fixed volume of liquid very accurately, while a burette allows the controlled release of variable volumes, often in titrations.
移液管用于非常精确地量取和转移固定体积的液体；而滴定管则允许可控地释放可变的液体体积，常用于滴定实验。
A graduated cylinder (measuring cylinder) is used to measure approximate volumes of liquids. It is more accurate than a beaker but less precise than a volumetric flask.
量筒（刻度量筒）用于量取近似体积的液体。它比烧杯精确，但不及容量瓶精密。
Safety equipment: goggles protect eyes; a heatproof mat protects the bench; tongs or a test tube holder prevent burns when handling hot glassware.
安全设备：护目镜保护眼睛；隔热垫保护实验台；坩埚钳或试管夹可在夹取热的玻璃仪器时防止烫伤。
10. Mnemonics and Memory Hacks for Chemistry | 化学的记忆术与记忆窍门
To remember diatomic elements (elements that exist as two‑atom molecules), use the mnemonic: Have No Fear Of Ice Cold Beer — Hydrogen (H₂), Nitrogen (N₂), Fluorine (F₂), Oxygen (O₂), Iodine (I₂), Chlorine (Cl₂), Bromine (Br₂).
要记住双原子分子元素（以双原子分子形式存在的元素），可以使用助记句：“Have No Fear Of Ice Cold Beer” ——氢气（H₂）、氮气（N₂）、氟气（F₂）、氧气（O₂）、碘（I₂）、氯气（Cl₂）、溴（Br₂）。
The order of reactivity for common metals can be recalled with: Please Stop Calling Me A Zebra In The Library — Potassium, Sodium, Calcium, Magnesium, Aluminium, Zinc, Iron, Tin, Lead, plus add Copper, Silver, Gold. Remember that more reactive metals displace less reactive ones from compounds.
常见金属的活动性顺序可用助记句记忆：“Please Stop Calling Me A Zebra In The Library” ——钾（K）、钠（Na）、钙（Ca）、镁（Mg）、铝（Al）、锌（Zn）、铁（Fe）、锡（Sn）、铅（Pb），还要加上铜（Cu）、银（Ag）、金（Au）。记住，活动性强的金属能把活动性弱的金属从其化合物中置换出来。
To recall the colours of universal indicator solutions, associate: Red = Raging Acid (pH 1‑3), Orange/ Yellow = Still Sour (pH 4‑6), Green = Neutral (pH 7), Blue = Basic but Gentle (pH 8‑11), Purple = Powerful Alkali (pH 12‑14).
要记住通用指示剂的颜色，可以联想：红色 = 剧烈的酸（pH 1‑3），橙色/黄色 = 仍然酸（pH 4‑6），绿色 = 中性（pH 7），蓝色 = 温和的碱（pH 8‑11），紫色 = 强碱（pH 12‑14）。
When balancing equations, always count the number of each type of atom on the left (reactants) and right (products). Balance by changing only the large numbers in front of formulas, never the small subscripts. Think: “Balance big, never sub.”
配平方程式时，永远先数清左侧（反应物）和右侧（生成物）每一种原子的数目。只改变化学式前的大数字（系数），绝不要改动右下角的小数字。牢记：“只能改大数，永远不改下标。”
The difference between physical and chemical change is like folding paper (physical) versus burning paper (chemical). If the substance’s molecules stay the same, it is physical. If new substances with new properties form, it is chemical.
物理变化和化学变化的区别就像折纸（物理变化）与烧纸（化学变化）。如果物质的分子保持不变，就是物理变化；如果产生了具有新性质的新物质，就是化学变化。
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