📚 Year 9 CCEA Chemistry: Vocabulary & Terminology Quick Memorisation Guide | CCEA 9年级化学：词汇术语速记指南
Mastering the language of chemistry is one of the most powerful ways to unlock success in Year 9 CCEA Science. This guide breaks down essential vocabulary into clear, bite-sized explanations, linking each term to memorable imagery and practical examples. Use it as a quick-reference glossary and a revision companion to build confidence with the key concepts you will meet in class, from atomic structure and the periodic table to chemical reactions and energy changes.
掌握化学语言是打开CCEA 9年级科学成功之门的最有力方式之一。本指南将核心词汇分解为清晰、易消化的解释，并将每个术语与好记的图像和实际例子联系起来。你可以把它当作快速参考词汇表与复习伙伴，用它来建立信心，从容应对课堂上从原子结构、元素周期表到化学反应与能量变化的关键概念。
1. Atoms, Elements and Compounds | 原子、元素与化合物
Atom: The smallest particle of an element that can still take part in a chemical reaction. Atoms are the fundamental building blocks of all matter.
原子：元素中能够参与化学反应的最小粒子。原子是所有物质的基本构建单元。
Element: A pure substance made up of only one type of atom. Examples include oxygen (O₂), iron (Fe) and gold (Au). An element cannot be broken down into simpler substances by chemical means.
元素：由同一种原子组成的纯物质。例如氧气（O₂）、铁（Fe）和金（Au）。元素无法通过化学方法分解为更简单的物质。
Compound: A substance formed when two or more different elements are chemically joined in fixed proportions. Compounds have properties that are different from their constituent elements. Water (H₂O) is a compound of hydrogen and oxygen.
化合物：当两种或多种不同元素以固定比例通过化学方式结合而成的物质。化合物的性质与其组成元素不同。水（H₂O）是氢和氧的化合物。
Mixture: Two or more substances that are physically combined but not chemically bonded. Mixtures can be separated by physical techniques. Air is a mixture of gases, and salt water is a mixture of salt and water.
混合物：两种或多种物质通过物理方式混合，没有发生化学结合。混合物可以通过物理技术分离。空气是气体的混合物，盐水是盐和水的混合物。
A quick way to remember the difference: elements are single letters in the alphabet of matter, compounds are fixed words built from those letters, and mixtures are loose sentences that can be pulled apart again without breaking anything.
记住区别的简便方法：元素是物质字母表中的单个字母，化合物是用这些字母拼出的固定单词，而混合物则是松散组合的句子，可以再次拆开而不会破坏任何东西。
| Term | Joined chemically? | Fixed ratio? | Example |
| Element | No | Single atom type | Fe, O₂, Au |
| Compound | Yes | Yes | H₂O, CO₂ |
| Mixture | No | No | Air, salt water |
2. Atomic Structure and Sub-atomic Particles | 原子结构与亚原子粒子
Proton: A positively charged particle found in the nucleus of an atom. Its relative charge is +1 and its relative mass is 1. The number of protons defines which element an atom is.
质子：位于原子核内、带正电的粒子。它的相对电荷为 +1，相对质量为 1。质子的数量决定了一个原子属于哪种元素。
Neutron: A neutral particle found in the nucleus. Its relative charge is 0 and its relative mass is 1. Neutrons hold the nucleus together and create different isotopes of the same element.
中子：位于原子核内、不带电的粒子。它的相对电荷为 0，相对质量为 1。中子将原子核维系在一起，并形成同一种元素的不同同位素。
Electron: A negatively charged particle that orbits the nucleus in shells or energy levels. Its relative charge is -1 and its relative mass is about 1/1840, so we usually treat it as negligible.
电子：带负电、在原子核外的电子层或能级上运动的粒子。它的相对电荷为 -1，相对质量约为 1/1840，因此通常忽略不计。
Atomic number: The number of protons in an atom. In a neutral atom, it also equals the number of electrons. Atomic number is the true identity card of an element.
原子序数：原子中质子的数量。在中性原子中，它也等于电子数。原子序数是一种元素真正的身份证。
Mass number: The total number of protons plus neutrons in an atom. Electrons are ignored because their mass is so small.
质量数：原子中质子与中子的总数。电子因质量极小而被忽略。
Mass number = protons + neutrons
质量数 = 质子数 + 中子数
Isotopes: Atoms of the same element with the same number of protons but different numbers of neutrons. Chlorine-35 and chlorine-37 are isotopes, which is why the relative atomic mass of chlorine is 35.5 rather than a whole number.
同位素：同一种元素的原子，质子数相同但中子数不同。氯-35和氯-37就是同位素，这也是为什么氯的相对原子质量是 35.5 而非整数。
3. The Periodic Table | 元素周期表
Periodic table: A chart in which all known elements are arranged in order of increasing atomic number, so that elements with similar properties line up in the same column.
元素周期表：一张将所有已知元素按原子序数递增排列的图表，使性质相似的元素排在同一列中。
Group: A vertical column in the periodic table. Elements in the same group have the same number of electrons in their outer shell, so they react in similar ways. Group 1 elements all have one outer electron.
族：元素周期表中的竖列。同一族的元素最外层电子数相同，因此反应方式相似。第 1 族元素都只有 1 个最外层电子。
Period: A horizontal row in the periodic table. The period number tells you how many electron shells an atom has. Sodium is in Period 3, so it has three occupied shells.
周期：元素周期表中的横行。周期数告诉你原子有几个电子层。钠位于第 3 周期，因此它有 3 个被占用的电子层。
Metals and non-metals: Most elements on the left and centre are metals, which are shiny, malleable, ductile and good conductors. Non-metals sit towards the top right and are usually dull, brittle and poor conductors.
金属与非金属：左侧和中部的大多数元素是金属，具有光泽、可延展、可拉丝并且导电导热良好。非金属位于右上方，通常暗淡、易碎且导电性差。
Alkali metals, halogens and noble gases: Group 1 metals react vigorously with water, Group 7 halogens are reactive non-metals used in disinfectants, and Group 0 noble gases such as helium and neon are unreactive because their outer shells are full.
碱金属、卤素与稀有气体：第 1 族碱金属与水剧烈反应，第 7 族卤素是用于消毒剂的活泼非金属，而第 0 族稀有气体如氦和氖因最外层电子已满而十分稳定。
4. Chemical Symbols, Formulae and Equations | 化学符号、化学式与方程式
Chemical symbol: A one- or two-letter code for an element, such as C for carbon, Ca for calcium or Na for sodium. The first letter is always a capital and the second is always lower case.
化学符号：表示元素的 1 至 2 个字母代码，例如碳是 C、钙是 Ca、钠是 Na。第一个字母必须大写，第二个字母必须小写。
Chemical formula: A shorthand way of showing the atoms in a substance using symbols and subscripts, such as CO₂, H₂SO₄ or CaCO₃. A subscript tells you how many atoms of that element are present.
化学式：用符号和下标表示物质中原子构成的简写方式，例如 CO₂、H₂SO₄ 或 CaCO₃。下标告诉你该元素原子的数量。
Word equation: ing an arrow to mean changes into, for example: methane + oxygen → carbon dioxide + water.
文字方程式：用文字书写的反应式，用箭头表示生成，例如：甲烷 + 氧气 → 二氧化碳 + 水。
Symbol equation: numbers in front are called coefficients and they count whole particles, not single atoms.
符号方程式：用化学式写出的同一反应：CH₄ + 2O₂ → CO₂ + 2H₂O。前面的大数字称为系数，它们计数的是整个粒子而不是单个原子。
Balanced equation: An equation in which the number of atoms of each element is the same on both sides, because mass is conserved in a chemical reaction. You balance equations by changing coefficients only, never subscripts.
配平方程式：反应前后每种元素原子数完全相同的方程式，因为化学反应中质量守恒。配平时只能改变系数，绝不能修改下标。
State symbols: Letters in brackets that show the physical state of each substance: (s) for solid, (l) for liquid, (g) for gas and (aq) for aqueous, meaning dissolved in water.
状态符号：括号中的字母表示各物质的物理状态：(s) 固体、(l) 液体、(g) 气体、(aq) 水溶液，即溶解在水中。
5. Chemical Reactions and Reaction Types | 化学反应与反应类型
Chemical reaction: A change in which new substances are formed, usually with an observable sign such as a gas being produced, a colour change, a temperature change or a solid precipitate appearing.
化学反应：生成新物质的变化，通常伴随可观察的现象，例如产生气体、颜色变化、温度变化或出现固体沉淀。
Reactants and products: Reactants are the starting substances on the left of the arrow; products are the new substances formed on the right. In a closed system, the total mass of reactants equals the total mass of products.
反应物与生成物：反应物是箭头左侧的起始物质；生成物是右侧生成的新物质。在封闭体系中，反应物总质量等于生成物总质量。
Combustion: Burning a fuel in oxygen, releasing energy. Complete combustion of a hydrocarbon produces carbon dioxide and water, while incomplete combustion can also produce carbon monoxide and soot.
燃烧：燃料在氧气中燃烧并释放能量。烃完全燃烧生成二氧化碳和水，不完全燃烧则还可能产生一氧化碳和烟灰。
Oxidation and reduction: Oxidation is the gain of oxygen or the loss of electrons; reduction is the loss of oxygen or the gain of electrons. The two always happen together.
氧化与还原：氧化是得到氧或失去电子；还原是失去氧或得到电子。两者总是同时发生。
Thermal decomposition: Breaking down a compound using heat, for example heating calcium carbonate to form calcium oxide and carbon dioxide.
热分解：利用加热使化合物分解，例如加热碳酸钙生成氧化钙和二氧化碳。
Displacement: A more reactive element pushing out a less reactive one from its compound. A classic example is iron nails in copper sulfate solution turning orange-brown as copper is deposited.
置换反应：较活泼的元素把较不活泼的元素从其化合物中排挤出来。经典例子是铁钉放入硫酸铜溶液后表面析出铜而变成橙褐色。
6. Acids, Bases, Alkalis and pH | 酸、碱、碱液与 pH
Acid: A substance that produces hydrogen ions (H⁺) in aqueous solution, has a pH below 7 and turns blue litmus paper red. Examples are hydrochloric acid and sulfuric acid.
酸：在水溶液中产生氢离子（H⁺）的物质，pH 低于 7，能使蓝色石蕊试纸变红。例如盐酸和硫酸。
Base: A substance that can neutralise an acid to form a salt and water. A base that is soluble in water is called an alkali.
碱：能夠与酸中和生成盐和水的物质。能溶于水的碱称为碱液。
Alkali: A soluble base that produces hydroxide ions (OH⁻) in solution, has a pH above 7 and turns red litmus paper blue. Examples are sodium hydroxide and ammonia solution.
碱液：可溶的碱，在溶液中产生氢氧根离子（OH⁻），pH 高于 7，能使红色石蕊试纸变蓝。例如氢氧化钠和氨水。
Indicator: A substance that changes colour to show whether a solution is acidic or alkaline. Litmus and universal indicator are the standard examples, while phenolphthalein is colourless in acid and pink in alkali.
指示剂：通过颜色变化显示溶液是酸性还是碱性的物质。石蕊和万能指示剂是标准例子，而酚酞在酸中无色、在碱中呈粉红色。
pH < 7 → acidic | pH = 7 → neutral | pH > 7 → alkaline
pH < 7 → 酸性 | pH = 7 → 中性 | pH > 7 → 碱性
Neutralisation: d water: acid + base → salt + water. Antacid tablets work this way to relieve indigestion.
中和反应：酸与碱反应生成盐和水：酸 + 碱 → 盐 + 水。抗酸药片正是通过这种方式缓解胃部不适。
Salt: The compound formed when the hydrogen of an acid is replaced by a metal or ammonium ion. Hydrochloric acid makes chlorides, sulfuric acid makes sulfates and nitric acid makes nitrates.
盐：酸中的氢被金属离子或铵根离子取代后生成的化合物。盐酸生成氯化物，硫酸生成硫酸盐，硝酸生成硝酸盐。
7. Energy Changes in Reactions | 反应中的能量变化
Exothermic reaction: A reaction that transfers energy to the surroundings, usually as heat, so the temperature rises. Combustion and neutralisation are classic exothermic reactions.
放热反应：向环境释放能量（通常为热能）的反应，因此温度升高。燃烧和中和都是典型的放热反应。
Endothermic reaction: A reaction that takes energy in from the surroundings, so the temperature falls. Thermal decomposition and photosynthesis are endothermic processes.
吸热反应：从环境吸收能量的反应，因此温度下降。热分解和光合作用是吸热过程。
Activation energy: The minimum energy that colliding particles need in order for a reaction to start. It is often drawn as the hump at the start of an energy profile diagram.
活化能：碰撞粒子开始反应所需的最低能量。在能量变化图上通常画成起点的能量峰。
Bond breaking = energy in | Bond making = energy out
断键 = 吸收能量 | 成键 = 放出能量
Bond energy: The energy needed to break one mole of a particular bond, or released when it forms. If more energy is released in bond making than taken in by bond breaking, the overall reaction is exothermic.
键能：断裂 1 摩尔某种化学键所需的能量，或形成该键时释放的能量。如果成键释放的能量多于断键吸收的能量，整体反应就是放热的。
Energy profile diagram: A graph plotting energy against the progress of a reaction. Reactants start on the left, products finish on the right, and the shape of the curve shows whether energy is released or absorbed overall.
能量变化图：以能量对反应进程作图的曲线图。反应物从左侧开始，生成物在右侧结束，曲线的形状显示整体上是释放还是吸收能量。
8. Mixtures and Separation Techniques | 混合物与分离技术
Solution: A mixture formed when a solute dissolves in a solvent, producing a transparent liquid that will not separate on standing. Salt dissolved in water is a solution.
溶液：溶质溶解在溶剂中形成的混合物，得到静置也不会分层的透明液体。盐溶于水就是溶液。
Solute and solvent: The solute is the substance that dissolves, usually present in the smaller amount; the solvent is the liquid that does the dissolving, usually present in the larger amount.
溶质与溶剂：溶质是溶解的物质，通常量较少；溶剂是进行溶解的液体，通常量较多。
Filtration: Separating an insoluble solid from a liquid using filter paper and a funnel. It works because the paper traps the larger solid particles while the liquid passes through.
过滤：使用滤纸和漏斗将不溶性固体与液体分离。其原理是滤纸截留较大的固体颗粒，而液体得以通过。
Evaporation and crystallisation: Separating a dissolved solid from its solution by heating gently to drive off the solvent, leaving crystals behind. This is how salt is obtained from salt water.
蒸发与结晶：通过温和加热使溶剂挥发，从而把溶解的固体从其溶液中分离出来，留下晶体。海水晒盐就是这一原理。
Simple distillation: Separating a solvent from a solution by boiling it off and condensing the vapour back into a liquid, using a condenser.
简单蒸馏：通过加热使溶剂汽化，再用冷凝管将蒸气冷凝回液体，从而把溶剂从溶液中分离出来。
Fractional distillation: Separating a mixture of liquids with different boiling points, such as the gases in air or the fractions of crude oil. The liquid with the lowest boiling point distils over first.
分馏：分离沸点不同的液体混合物，例如空气的组成气体或原油的各馏分。沸点最低的液体最先蒸馏出来。
Chromatography: Separating coloured substances using a solvent moving up paper. The most soluble substance travels furthest up the paper. It can also be used to test the purity of a substance.
色谱法：利用溶剂在纸上向上移动来分离有色物质。溶解度最大的物质在纸上移动得最远。它也可用于检验物质的纯度。
9. Rates of Reaction and Catalysts | 反应速率与催化剂
Rate of reaction: How fast reactants are used up or products are formed. It can be measured by gas volume produced, mass lost or the time taken for a cross to disappear.
反应速率：反应物被消耗或生成物生成的快慢。可通过产生的气体体积、质量损失或十字标记消失的时间来测量。
Collision theory: For a reaction to happen, particles must collide with at least the activation energy. Anything that increases the frequency or energy of successful collisions increases the rate.
碰撞理论：反应发生的前提是粒子碰撞时至少具有活化能。任何增加有效碰撞频率或能量的因素都会提高反应速率。
Factors affecting rate: Temperature, concentration, pressure of gases, surface area of solids and the presence of a catalyst all change the rate of a reaction.
影响速率的因素：温度、浓度、气体压强、固体的表面积以及是否有催化剂，都会改变反应速率。
Surface area: Breaking a solid into smaller pieces exposes more particles to attack by the other reactant. Powdered marble reacts much faster with acid than a single large chip.
表面积：把固体打碎成小块会使更多粒子暴露出来与另一反应物接触。粉末状大理石与酸反应的速度远快于一整块大理石。
Catalyst: A substance that speeds up a reaction without being used up itself. It lowers the activation energy by providing an alternative pathway, and it does not change the products formed.
催化剂：能加快反应而本身不被消耗的物质。它通过提供另一条反应路径降低活化能，并且不改变生成物。
10. Quantitative Chemistry Basics | 定量化学基础
Conservation of mass: In a chemical reaction, the total mass of the reactants equals the total mass of the products, provided the system is closed. This is why equations must be balanced.
质量守恒：在封闭体系中，化学反应中反应物的总质量等于生成物的总质量。这正是方程式必须配平的原因。
Relative atomic mass (Aᵣ): The average mass of the atoms of an element compared with 1/12 of the mass of a carbon-12 atom. It is the number usually shown above the symbol in the periodic table.
相对原子质量（Aᵣ）：元素原子的平均质量与碳-12 原子质量 1/12 的比值。通常是周期表元素符号上方的数字。
Relative formula mass (Mᵣ): e relative atomic masses of all the atoms in a formula. For water: Mᵣ = (2 × 1) + 16 = 18.
相对分子质量（Mᵣ）：化学式中所有原子的相对原子质量之和。对水而言：Mᵣ = (2 × 1) + 16 = 18。
Mᵣ = Σ (Aᵣ of each atom × number of atoms)
Mᵣ = Σ（各原子 Aᵣ × 原子个数）
Mole: The amount of substance that contains 6.02 × 10²³ particles, known as Avogadro's number. One mole of carbon has a mass of 12 g.
摩尔：含有 6.02 × 10²³ 个粒子的物质的量，该常数称为阿伏加德罗常数。1 摩尔碳的质量为 12 g。
moles (n) = mass (m) ÷ molar mass (M)
物质的量 (n) = 质量 (m) ÷ 摩尔质量 (M)
Concentration: The amount of solute dissolved in a given volume of solution, usually measured in g/dm³ or mol/dm³. Adding water decreases the concentration without changing the number of moles.
浓度：一定体积溶液中溶解的溶质量，通常以 g/dm³ 或 mol/dm³ 表示。加水会降低浓度，但不会改变溶质的物质的量。
Percentage yield: The actual mass of product obtained divided by the theoretical mass, multiplied by 100. Yields are always below 100 percent because of incomplete reactions and losses during transfer.
产率：实际得到的产物质量除以理论质量再乘以 100。由于反应不完全和转移过程损失，产率总是低于 100%。
11. Memory Techniques for Chemistry Vocabulary | 化学词汇记忆技巧
Use word roots: Many terms hide their meaning in prefixes and suffixes. Mono- means one, di- means two, poly- means many, -ide means a compound of two elements, and -ate often means a compound containing oxygen.
善用词根：许多术语的含义藏在前后缀里。mono- 表示一，di- 表示二，poly- 表示多，-ide 表示两种元素组成的化合物，-ate 通常表示含氧化合物。
Chunk the list: Do not try to learn sixty words in one sitting. Group them by topic, such as atoms, acids
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