📚 Year 7 Edexcel Chemistry: Transition Guide | Year 7 Edexcel 化学：升学衔接指南
Starting Year 7 is a big step – you move from general primary science into subject-specific chemistry. This transition guide will walk you through everything you need to know for Edexcel Key Stage 3 Chemistry, from lab safety and particles to simple reactions. By the end, you will feel confident, curious, and ready to excel.
从小学升入七年级是一个重要的跨越——你将从综合科学进入分科化学的学习。这份衔接指南将带你了解 Edexcel Key Stage 3 化学所需掌握的全部内容，从实验室安全、粒子模型到简单的化学反应。读完之后，你将充满信心与好奇，为学好化学做好充分准备。
1. Welcome to the World of Chemistry | 欢迎进入化学世界
Chemistry is the study of matter – what everything is made of, how substances behave, and how they change into new materials. In Year 7, you will discover why ice melts, how metals rust, and what happens when you bake a cake. The Edexcel course builds on your KS2 science, introducing more advanced concepts and practical skills that will stay with you throughout secondary school.
化学是研究物质的科学——研究一切由什么构成、物质如何表现、以及它们如何变成新的材料。在七年级，你将探索冰为什么会融化、金属怎样生锈、以及烤蛋糕时发生了什么。Edexcel 课程在你小学科学的基础上，提出了更深层的概念和实验技能，这些将伴随你整个中学阶段。
2. Lab Safety and Essential Equipment | 实验室安全与必备器材
Safety is always the first rule in a chemistry lab. You must learn how to work responsibly to protect yourself and others. Below are the key safety rules you must follow every time you enter the lab.
在化学实验室里，安全永远是第一规则。你必须学会负责任地操作，保护自己和他人。以下是每次进入实验室都必须遵守的关键安全规则。
Always wear safety goggles to shield your eyes from splashes and fumes.
始终佩戴护目镜，防止液体溅射和气体刺激眼睛。
Tie back long hair and tuck in loose clothing or ties.
将长发束起，并将宽松衣物或领带塞好。
Know the location of the fire extinguisher, fire blanket, and eyewash station before starting any experiment.
开始实验前，务必知道灭火器、灭火毯和洗眼器的位置。
Never eat, drink, or run in the laboratory.
严禁在实验室饮食或奔跑。
Always listen to your teacher's instructions and read labels carefully.
始终听从老师的指导并仔细阅读标签。
You will also use a range of equipment. Familiarising yourself with their names and functions will make practical lessons much smoother.
你还会用到一系列器材。熟悉它们的名称和用途会让实验课顺利得多。
Beaker – a wide glass container for mixing, heating, and holding liquids.
烧杯 – 宽口玻璃容器，用于混合、加热和盛放液体。
Conical flask – a narrow-necked glass container used when swirling liquids to mix them, reducing the risk of splashes.
锥形瓶 – 细颈玻璃容器，用于摇荡液体进行混合，可减少液体飞溅的风险。
Test tube – a small glass tube ideal for observing reactions on a small scale.
试管 – 小号玻璃管，非常适合小量反应观察。
Bunsen burner – used for heating; can produce a luminous yellow safety flame or a roaring blue heating flame.
本生灯 – 用于加热；可产生可见的黄色安全火焰或炽热的蓝色加热火焰。
Measuring cylinder – measures approximate volumes of liquids.
量筒 – 用于测量液体的大致体积。
3. Scientific Enquiry Skills | 科学探究技能
In Edexcel Chemistry, you do not just learn facts – you learn to think like a scientist. You will plan investigations, identify variables, and record data accurately.
在 Edexcel 化学课程中，你不仅要学习知识，还要学着像科学家一样思考。你将设计探究方案、识别变量并准确记录数据。
Independent variable – the factor you change on purpose.
自变量 – 你故意改变的因素。
Dependent variable – the factor you measure or observe as a result.
因变量 – 你测量或观察到的结果因素。
Control variables – all the factors that must be kept the same to ensure a fair test.
控制变量 – 所有必须保持不变的因素，以保证实验的公平性。
You will also learn to write a clear prediction, record results in tables, plot graphs, and write conclusions. These skills are essential not only in chemistry but across all sciences.
你还将学会写出清晰的预测、用表格记录结果、绘制图表并撰写结论。这些技能不仅在化学中至关重要，在所有科学科目中都是如此。
4. States of Matter and the Particle Model | 物质的三态与粒子模型
Everything around you is made of tiny particles. The arrangement and movement of these particles determine whether a substance is a solid, a liquid, or a gas.
你周围的一切都由微小粒子构成。这些粒子的排列方式和运动状态决定了物质是固态、液态还是气态。
In solids, particles are packed tightly in a regular pattern and can only vibrate in fixed positions. Solids have a fixed shape and a fixed volume.
在固态中，粒子紧密堆积成规则的模式，只能在固定位置上振动。固体有固定的形状和固定的体积。
In liquids, particles are close together but not in a fixed arrangement; they can slide past each other. Liquids have a fixed volume but take the shape of the bottom part of their container.
在液态中，粒子彼此靠近但没有固定的排列方式；它们可以相互滑动。液体有固定的体积，但会呈现容器底部的形状。
In gases, particles are far apart and move randomly at high speed. Gases have no fixed shape or volume and will spread out to fill any container.
在气态中，粒子相距很远，并高速随机运动。气体没有固定的形状或体积，会扩散并充满整个容器。
When you heat a substance, particles gain energy and move more vigorously. This explains melting, boiling, and expansion. The reverse happens on cooling.
当你加热物质时，粒子获得能量，运动更剧烈。这就解释了熔化、沸腾和膨胀。冷却时则发生相反的过程。
5. Atoms, Elements and the Periodic Table | 原子、元素与元素周期表入门
An atom is the smallest part of an element that can take part in a chemical reaction. An element is a substance made of only one type of atom. All known elements are arranged in the Periodic Table.
原子是能参与化学反应的元素最小粒子。元素是仅由一种原子组成的物质。所有已知元素都被排列在元素周期表中。
In Year 7, you will learn the symbols of the first 20 elements and recognise that metals are on the left and non‑metals on the right of the table. Here are some key elements to remember:
在七年级，你将学习前 20 号元素的符号，并认识金属在表的左边、非金属在右边。下面是一些需要记住的关键元素：
Hydrogen (H) – the lightest element, a colourless gas.
氢 (H) – 最轻的元素，一种无色气体。
Carbon (C) – found in all living things; can be graphite or diamond.
碳 (C) – 存在于所有生物体内；可以是石墨或金刚石。
Oxygen (O) – a gas vital for respiration and combustion.
氧 (O) – 对呼吸和燃烧至关重要的气体。
Sodium (Na) – a soft, highly reactive metal stored under oil.
钠 (Na) – 一种柔软的、高度活泼的金属，需保存在油中。
Chlorine (Cl) – a poisonous greenish gas used in water treatment.
氯 (Cl) – 一种有毒的浅绿色气体，用于水处理。
Iron (Fe) – a strong magnetic metal used in construction.
铁 (Fe) – 一种有磁性的坚固金属，用于建筑。
6. Compounds and Chemical Formulae | 化合物与化学式
When two or more different elements chemically combine, they form a compound. The properties of a compound are completely different from the elements that make it. For example, sodium is a reactive metal, chlorine is a toxic gas, but together they make sodium chloride – table salt, which is safe to eat.
当两种或多种不同元素通过化学方式结合时，就形成了化合物。化合物的性质与其组成元素完全不同。例如，钠是一种活泼金属，氯是有毒气体，但两者结合生成氯化钠——食盐，可以安全食用。
A chemical formula uses symbols and small subscript numbers to show the types and ratios of atoms in a compound. For instance:
化学式使用元素符号和小下标数字表示化合物中原子的种类和个数比。例如：
Water: H₂O (2 hydrogen atoms, 1 oxygen atom)
水：H₂O（2 个氢原子，1 个氧原子）
Carbon dioxide: CO₂ (1 carbon, 2 oxygens)
二氧化碳：CO₂（1 个碳原子，2 个氧原子）
Sulfuric acid: H₂SO₄ (2 H, 1 S, 4 O)
硫酸：H₂SO₄（2 个氢原子，1 个硫原子，4 个氧原子）
You will practise writing simple formulae and interpreting what they tell you about the particles present.
你将练习书写简单的化学式，并诠释它们所包含的粒子信息。
7. Physical and Chemical Changes | 物理变化与化学变化
One of the most important distinctions in chemistry is between physical and chemical changes. A physical change alters the state or appearance of a substance but does not produce a new substance. Examples include melting ice, tearing paper, or dissolving sugar in water. These changes are usually easy to reverse.
化学中最重要的区别之一就是物理变化和化学变化。物理变化改变物质的状态或外观，但不产生新物质，例如冰融化、撕纸或糖溶在水里。这些变化通常容易逆转。
A chemical change, however, creates one or more new substances with different properties. It is often accompanied by signs such as a colour change, a temperature change (without heating/cooling), bubbles of gas appearing, or a solid precipitate forming. Examples include frying an egg, rusting iron, or burning wood. Most chemical changes are not easily reversed.
而化学变化则会生成一种或多种性质不同的新物质。它常常伴有以下现象：颜色改变、温度自发变化（非加热或冷却所致）、产生气泡或形成固体沉淀。例如煎鸡蛋、铁生锈或木头燃烧。大多数化学变化不易逆转。
Word equation: Iron + Oxygen → Iron oxide (rust)
文字方程式：铁 + 氧气 → 氧化铁（铁锈）
8. Pure Substances and Mixtures | 纯净物与混合物
A pure substance consists of only one type of element or compound, and has a fixed melting point and boiling point. A mixture, on the other hand, contains two or more different substances that are not chemically joined. Mixtures can be separated into their components by physical methods.
纯净物只由一种元素或化合物组成，具有固定的熔点和沸点。而混合物则包含两种或多种未通过化学键结合的不同物质，可以通过物理方法将其分离成各个组分。
In the lab, distilled water is a pure substance (it boils at exactly 100 °C), while seawater or ink is a mixture. Understanding this difference is crucial for you when you start using separation techniques.
在实验室中，蒸馏水是纯净物（恰好在 100 °C 沸腾），而海水或墨水是混合物。理解这一区别对你之后学习分离技术至关重要。
9. Introduction to Separation Techniques | 分离技术简介
Since mixtures can be separated physically, chemists use a range of separation techniques depending on the type of mixture. In Year 7, you will explore some of the most common ones.
由于混合物可通过物理手段分离，化学家根据混合物类型使用一系列分离技术。七年级，你将探索其中最常用的几种。
Filtration – separates an insoluble solid from a liquid. The liquid passes through filter paper, leaving the solid behind.
过滤 – 将不溶性固体从液体中分离出来。液体透过滤纸，留下固体。
Evaporation – removes a solvent (usually water) by heating, leaving dissolved solid behind. Used to obtain salt from saltwater.
蒸发 – 通过加热除去溶剂（通常是水），留下溶解的固体。用于从盐水中获取食盐。
Distillation – separates a solvent from a solution by boiling and then condensing the vapour. It collects the pure liquid and leaves the solute behind.
蒸馏 – 通过煮沸溶液再冷凝蒸汽来分离溶剂与溶质。它能收集纯液体并将溶质留在烧瓶中。
Chromatography – separates dissolved substances that have different solubilities. You will often use paper chromatography to separate the dyes in ink.
色谱法 – 分离溶解度不同的溶解物质。你经常会用纸色谱法分离墨水中的染料。
10. Acids and Alkalis – A First Look | 酸与碱初探
Acids and alkalis are two important families of chemicals. Acids have a sour taste (you must never taste them in the lab!) and turn blue litmus paper red. Common laboratory acids include hydrochloric acid (HCl), sulfuric acid (H₂SO₄), and nitric acid (HNO₃).
酸和碱是两大重要的化学物质家族。酸有酸味（绝不能在实验室品尝！），能使蓝色石蕊试纸变红。实验室常见的酸包括盐酸 (HCl)、硫酸 (H₂SO₄) 和硝酸 (HNO₃)。
Alkalis are soluble bases. They feel soapy and turn red litmus paper blue. Sodium hydroxide (NaOH) and potassium hydroxide (KOH) are typical alkalis.
碱是可溶的碱性物质，摸起来有滑腻感，能使红色石蕊试纸变蓝。氢氧化钠 (NaOH) 和氢氧化钾 (KOH) 是典型的碱。
The pH scale shows how acidic or alkaline a solution is, ranging from 0 (strongly acidic) to 14 (strongly alkaline), with 7 being neutral (like pure water). You will use universal indicator or pH paper to estimate pH values.
pH 标度表示溶液的酸碱性，范围从 0（强酸）到 14（强碱），7 为中性（如纯水）。你将使用通用指示剂或 pH 试纸估算 pH 值。
Neutralisation: Acid + Alkali → Salt + Water
中和反应：酸 + 碱 → 盐 + 水
