📚 Core Knowledge Checklist for Year 9 SQA Chemistry | Year 9 SQA 化学核心知识点梳理
This article brings together the essential ideas you need to master in Year 9 SQA Chemistry. Each section pairs a short English explanation with a matching Chinese version so you can check your understanding in both languages. Use it as a final revision checklist or as a quick reference whenever you need to refresh a topic.
本文梳理了 Year 9 SQA 化学学科必须掌握的核心知识点。每个小节都先用英文阐述要点，再给出对应的中文解释，方便你进行双语自查。你可以把它当作考前复习清单，也可以在学习任何主题时快速查阅。
1. States of Matter and the Particle Model | 物质的状态与粒子模型
All substances are made of tiny particles. In solids the particles are arranged in a fixed, regular pattern and can only vibrate in place. In liquids the particles are still close together but can slide past each other. In gases the particles are far apart and move rapidly in all directions.
所有物质都由微小的粒子构成。固体粒子排列成固定、规则的图案，只能在原地振动。液体粒子仍然紧密聚集，但可以相互滑动。气体粒子彼此远离，朝各个方向快速运动。
Changes of state happen when particles gain or lose energy. Melting, boiling and evaporating are endothermic processes (energy is taken in), while freezing and condensing are exothermic (energy is given out). The melting point and boiling point are characteristic properties of a pure substance.
状态变化源于粒子获得或失去能量。熔化、沸腾和蒸发是吸热过程（吸收能量），凝固和冷凝是放热过程（释放能量）。熔点和沸点是纯物质的特征性质。
Sublimation is the change directly from solid to gas, e.g. dry ice (solid CO₂). Diffusion provides evidence that particles are moving randomly: a gas or a dissolved substance spreads from an area of high concentration to an area of low concentration.
升华是固体直接变成气体的过程，例如干冰（固态 CO₂）。扩散为粒子的无规则运动提供了证据：气体或溶解的物质会从高浓度区域向低浓度区域扩散。
2. Atoms, Elements and Compounds | 原子、元素与化合物
An atom is the smallest particle of an element that can take part in a chemical reaction. Elements contain only one type of atom and are listed on the Periodic Table. Around 100 different elements occur naturally.
原子是能参与化学反应的元素最小粒子。元素只包含一种类型的原子，均列在元素周期表中。自然界存在大约 100 种不同的元素。
Compounds are formed when atoms of two or more different elements are chemically bonded. A compound has properties completely different from the elements it contains. For example, sodium is a reactive metal, chlorine is a poisonous gas, but together they form sodium chloride (NaCl), ordinary table salt.
当两种或多种不同元素的原子通过化学键结合时就形成了化合物。化合物的性质与组成它的元素截然不同。例如，钠是活泼金属，氯是有毒气体，但它们结合形成氯化钠 (NaCl)，也就是普通的食盐。
Chemical symbols are one- or two-letter abbreviations for elements. The first letter is always capitalised. The formula of a compound shows the symbols of the elements and the ratio of atoms, e.g. H₂O means two hydrogen atoms bonded to one oxygen atom.
化学符号是代表元素的一个或两个字母的缩写，首字母必须大写。化合物的化学式表示所含元素的符号及原子个数比，例如 H₂O 表示两个氢原子与一个氧原子键合。
3. The Periodic Table | 元素周期表
The Periodic Table arranges elements in order of increasing atomic number (number of protons). 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 outer-shell electrons.
元素周期表按原子序数（质子数）递增的顺序排列元素。纵列称为族，横排称为周期。同一族的元素具有相似的化学性质，因为它们的最外层电子数相同。
Group 1 elements are the alkali metals: lithium, sodium, potassium, etc. They are soft, very reactive, and react vigorously with water to produce a metal hydroxide and hydrogen gas. Their reactivity increases down the group.
第 1 族元素是碱金属：锂、钠、钾等。它们质地柔软，非常活泼，能与水剧烈反应生成金属氢氧化物和氢气。活泼性沿族向下增强。
Group 7 elements are the halogens: fluorine, chlorine, bromine, iodine. They are non‑metals that exist as diatomic molecules (F₂, Cl₂, etc.). Reactivity decreases down the group. Group 0, the noble gases, are monatomic and very unreactive because they have a full outer shell of electrons.
第 7 族元素是卤素：氟、氯、溴、碘。它们是双原子分子（F₂, Cl₂ 等）的非金属，活泼性沿族向下减弱。第 0 族是稀有气体，它们以单原子存在，因最外层电子已满而极不活泼。
4. Writing Chemical Formulae and Equations | 化学式与化学方程式的书写
A chemical formula uses element symbols and small subscript numbers to show the number of each type of atom in a substance. For ionic compounds the total positive charge must balance the total negative charge. For example, magnesium chloride contains Mg²⁺ and Cl⁻, so its formula is MgCl₂.
化学式用元素符号和小数字下标表示物质中各原子的数量。离子化合物的正负电荷总数必须平衡。例如氯化镁含有 Mg²⁺ 和 Cl⁻，因此化学式为 MgCl₂。
equation shows the numbers of atoms, with coefficients before each formula so that the same number of each type of atom appears on both sides.
文字方程式列出反应物和生成物的名称：如 镁 + 氧气 → 氧化镁。配平的符号方程式则显示原子数目，通过在各化学式前添加系数使方程式两边每种原子的总数相等。
2Mg + O₂ → 2MgO
State symbols can be added: (s) solid, (l) liquid, (g) gas, (aq) aqueous solution. They tell you the physical state of each substance under the reaction conditions.
可添加状态符号：(s) 固态、(l) 液态、(g) 气态、(aq) 水溶液。它们表明各物质在反应条件下的物理状态。
5. Acids, Alkalis 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 laboratory acids include hydrochloric acid (HCl), sulfuric acid (H₂SO₄) and nitric acid (HNO₃). An alkali is a soluble base that releases hydroxide ions (OH⁻) in water.
酸是溶于水时释放氢离子（H⁺）的物质。实验室常见的酸有盐酸 (HCl)、硫酸 (H₂SO₄) 和硝酸 (HNO₃)。碱是溶于水时释放氢氧根离子（OH⁻）的可溶性碱。
The pH scale goes from 0 to 14. Acids have a pH less than 7; alkalis have a pH greater than 7. A pH of 7 is neutral. Universal indicator turns different colours over the full pH range, while litmus only distinguishes acid (red) from alkali (blue).
pH 标度范围为 0 到 14。酸的 pH 小于 7，碱的 pH 大于 7，pH 等于 7 为中性。通用指示剂在整个 pH 区间显示不同颜色，而石蕊只能区分酸（红色）和碱（蓝色）。
Strong acids and alkalis are fully ionised in water, while weak ones are only partially ionised. The concentration tells you how much acid or alkali is dissolved in a given volume of water; it is different from strength.
强酸和强碱在水中完全电离，弱酸和弱碱仅部分电离。浓度指的是在一定体积水中溶解了多少酸或碱，它与酸碱的强弱是不同的概念。
6. Neutralisation and Making Salts | 中和反应与制备盐
When an acid reacts with an alkali, a neutralisation reaction takes place. The H⁺ ions from the acid combine with the OH⁻ ions from the alkali to form water, while the other ions form a salt.
H⁺(aq) + OH⁻(aq) → H₂O(l)
酸与碱反应时发生中和反应。酸中的 H⁺ 与碱中的 OH⁻ 结合生成水，其余的离子形成盐。
ves nitrates. For example, sodium hydroxide + hydrochloric acid → sodium chloride + water.
盐的名称取决于所用的酸：盐酸产生氯化物，硫酸产生硫酸盐，硝酸产生硝酸盐。例如：氢氧化钠 + 盐酸 → 氯化钠 + 水。
Acids also react with metal oxides, metal hydroxides and metal carbonates to produce a salt and water (and carbon dioxide in the case of carbonates). Crystals of the salt can be obtained by neutralising the acid, then gently evaporating the solution.
酸也能与金属氧化物、金属氢氧化物和金属碳酸盐反应生成盐和水（碳酸盐还会放出二氧化碳）。可以用酸完全中和后，再通过缓慢蒸发溶液来得到盐的晶体。
7. Metals and Non‑metals | 金属与非金属
Metals are typically shiny, good conductors of heat and electricity, malleable and ductile. They tend to lose electrons and form positive ions. Non‑metals are usually dull, brittle (as solids), poor conductors, and they gain electrons to form negative ions or share electrons in covalent bonds.
金属通常有光泽，是热和电的良导体，具有延展性，容易失去电子形成阳离子。非金属一般无光泽，固态时质脆，导电导热性差，它们通过得到电子形成阴离子或通过共用电子形成共价键。
Most metals react with oxygen to form metal oxides, which are basic. Some metals, like iron, react slowly with oxygen and water to form rust (hydrated iron(III) oxide). Metals above hydrogen in the reactivity series react with dilute acids to produce a salt and hydrogen gas.
大多数金属与氧气反应生成碱性金属氧化物。有些金属，如铁，在水和氧气共同作用下缓慢生锈（水合氧化铁）。在活动性顺序中排在氢前的金属能与稀酸反应生成盐和氢气。
8. Reactivity Series and Displacement | 金属活动性顺序与置换反应
The reactivity series lists metals in order of their tendency to form positive ions. A typical order from most to least reactive is: potassium, sodium, calcium, magnesium, aluminium, zinc, iron, copper, silver, gold.
金属活动性顺序按照金属形成阳离子的倾向排列。从最活泼到最不活泼的常见顺序为：钾、钠、钙、镁、铝、锌、铁、铜、银、金。
: Mg(s) + CuSO₄(aq) → MgSO₄(aq) + Cu(s). This is a redox reaction; the more reactive metal is oxidised and the less reactive metal ion is reduced.
较活泼的金属能将较不活泼的金属从其化合物中置换出来。例如，镁可以从硫酸铜溶液中置换出铜：Mg(s) + CuSO₄(aq) → MgSO₄(aq) + Cu(s)。这是一个氧化还原反应，较活泼金属被氧化，较不活泼金属离子被还原。
The reactivity series also helps to explain how metals are extracted. Very reactive metals, like aluminium, are extracted by electrolysis; medium-reactive metals, like iron, are extracted by reduction with carbon; unreactive metals are found native.
活动性顺序也有助于解释金属的冶炼方法。极活泼的金属（如铝）用电解法冶炼；中等活泼的金属（如铁）用碳还原法冶炼；不活泼金属能以单质形态存在。
9. Rates of Reaction | 反应速率
The rate of a chemical reaction tells you how quickly reactants are used up or products are made. It can be measured by the volume of gas produced per unit time, the change in mass, or the time taken for a colour change or precipitate to appear.
化学反应速率表示反应物消耗或生成物产生的快慢。它可以通过测量单位时间产生的气体体积、质量变化，或颜色变化、出现沉淀所需的时间来测定。
Four main factors affect the rate: temperature, concentration (or pressure for gases), surface area of solids, and the use of a catalyst. Increasing temperature gives particles more kinetic energy, so they collide more frequently and with greater energy, increasing the number of successful collisions.
影响速率的四个主要因素是：温度、浓度（对气体则是压强）、固体的表面积以及催化剂。升高温度使粒子动能增大，碰撞更频繁且更有力，从而增加有效碰撞的次数。
Smaller solid pieces have a larger total surface area, which increases the frequency of collisions. A catalyst provides an alternative reaction pathway with a lower activation energy; it is not used up and can be recovered unchanged at the end.
固体颗粒越小，总表面积越大，碰撞频率就越高。催化剂提供了一条活化能较低的反应途径；它在反应中不被消耗，反应结束时可以原样回收。
10. Separation Techniques | 分离技术
Different separation methods are used depending on the physical properties of the components. Filtration separates an insoluble solid from a liquid, e.g. sand from water. The solid stays on the filter paper while the liquid (filtrate) passes through.
根据混合物中各组分的物理性质可选用不同的分离方法。过滤用于分离不溶性固体和液体，例如从水中分离沙子。固体留在滤纸上，液体（滤液）通过。
Evaporation is used to obtain a soluble salt from a solution, but crystallisation yields purer crystals by gently heating until crystals form on cooling. Distillation separates a solvent from a solution (simple distillation) or separates miscible liquids with different boiling points (fractional distillation).
蒸发可用于从溶液中获得可溶性盐，但结晶法通过缓慢加热再冷却析出晶体，能得到更纯的产物。蒸馏可以从溶液中分离溶剂（简单蒸馏），或分离沸点不同的互溶液体（分馏）。
Chromatography separates small amounts of dissolved substances, e.g. to separate the dyes in an ink. Each component travels a different distance up the paper, producing a chromatogram. An Rf value can be calculated to identify a substance.
色谱法用于分离少量溶解的物质，如分离墨水中的染料。各组分在纸上移动的距离不同，形成色谱图。可以通过计算 Rf 值来鉴别物质。
11. Earth's Atmosphere and Common Resources | 地球大气与常见资源
Air is a mixture of gases. The two main gases are nitrogen (about 78%) and oxygen (about 21%), with small amounts of argon (0.9%), carbon dioxide (0.04%) and water vapour. The test for oxygen is that it relights a glowing splint; carbon dioxide turns limewater milky.
空气是一种混合物，主要含氮气（约 78%）和氧气（约 21%），还有少量氩气 (0.9%)、二氧化碳 (0.04%) 和水蒸气。氧气的检验是能使带火星的木条复燃；二氧化碳能使石灰水变浑浊。
Burning fossil fuels releases carbon dioxide, a greenhouse gas that traps heat and contributes to climate change. Acid rain is caused by sulfur dioxide and nitrogen oxides dissolving in rainwater. These pollutants come mainly from burning fossil fuels in power stations and vehicles.
燃烧化石燃料释放二氧化碳，这是一种能捕获热量的温室气体，导致气候变化。酸雨由二氧化硫和氮氧化物溶于雨水形成，这些污染物主要来自发电站和汽车燃烧化石燃料。
The Earth provides many resources including minerals, ores and crude oil. Crude oil is a mixture of hydrocarbons that can be separated by fractional distillation. Renewable resources such as solar, wind and tidal energy are increasingly important.
地球提供了矿物、矿石和原油等多种资源。原油是碳氢化合物的混合物，可以通过分馏进行分离。太阳能、风能和潮汐能等可再生资源正变得日益重要。
12. Conservation of Mass and Simple Calculations | 质量守恒与简单计算
In a chemical reaction no atoms are created or destroyed; the total mass of the reactants equals the total mass of the products. This is the law of conservation of mass. In a closed system, the mass stays exactly the same. In an open system, a gas may escape, making it seem as though mass has been lost.
在化学反应中，原子既不会凭空产生也不会消失；反应物的总质量等于生成物的总质量，这就是质量守恒定律。在密闭系统中，质量完全不变。在开放系统中，气体可能逸出，使得质量看上去似乎减少了。
iron reacts with 3.2 g of sulfur, the mass of iron sulfide produced is 5.6 + 3.2 = 8.8 g.
如果已知反应中除一种物质外其他物质的质量，就可以利用质量守恒求出未知质量。例如，当 5.6 g 铁与 3.2 g 硫反应时，生成的硫化铁质量为 5.6 + 3.2 = 8.8 g。
Balanced equations also allow you to calculate reacting masses using relative atomic masses (Ar) and relative formula masses (Mr). At Year 9 level, you are expected to interpret simple mass relationships and show that atoms are rearranged, not lost.
配平的方程式还可以借助相对原子质量 (Ar) 和相对化学式质量 (Mr) 计算反应质量。Year 9 阶段要求能解释简单的质量关系，并说明原子只是重新组合，并未消失。
Published by TutorHao | Chemistry Revision Series | aleveler.com
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