📚 Year 7 AQA Chemistry: Core Knowledge Review | 核心知识点梳理
Welcome to this comprehensive review of the key concepts in Year 7 AQA Chemistry. This article covers the essential topics that form the foundation of chemistry at KS3, including states of matter, the particle model, elements and compounds, chemical reactions, acids and alkalis, separation techniques, and the properties of metals and non-metals. Each section is designed to help you consolidate your understanding and prepare confidently for assessments.
欢迎阅读这篇 Year 7 AQA 化学核心知识点全面梳理。本文将涵盖构成 KS3 化学基础的重要主题，包括物质的状态、粒子模型、元素和化合物、化学反应、酸和碱、分离技术以及金属与非金属的性质。每个小节旨在帮助你巩固理解，并为评估做好充分准备。
1. States of Matter | 物质的状态
All matter exists in one of three main states: solid, liquid or gas. Solids have a fixed shape and a fixed volume. Their particles are held tightly in a regular pattern and can only vibrate in place.
所有物质都以三种主要状态之一存在：固态、液态或气态。固体有固定的形状和固定的体积。它们的粒子被紧紧地固定在规则的排列中，只能在原地振动。
Liquids have a fixed volume but take the shape of their container. The particles are still close together, but they can slide past one another, allowing liquids to flow.
液体有固定的体积，但形状随容器而改变。粒子仍然紧密排列，但可以彼此滑动，因此液体能够流动。
Gases have no fixed shape and no fixed volume. They completely fill the container they are in. Gas particles are far apart and move rapidly in all directions.
气体没有固定的形状，也没有固定的体积。它们会完全充满所在的容器。气体粒子相距很远，并向各个方向快速运动。
2. The Particle Model | 粒子模型
The particle model explains the behaviour of solids, liquids and gases. It states that all substances are made of tiny particles that are constantly moving. In solids, the particles are arranged regularly and only vibrate. In liquids, the particles are arranged randomly but remain close, moving around each other. In gases, the particles are far apart and move quickly at high speeds.
粒子模型解释了固体、液体和气体的行为。该模型指出，所有物质都由不断运动的微小粒子构成。在固体中，粒子排列规则，仅能振动。在液体中，粒子排列不规则，但仍然靠近，可以相互绕动。在气体中，粒子相距很远且高速运动。
When a substance is heated, its particles gain energy. This can cause a change of state: melting (solid to liquid), boiling or evaporation (liquid to gas), condensation (gas to liquid) and freezing (liquid to solid). Sublimation occurs when a solid turns directly into a gas, such as solid carbon dioxide (dry ice).
当物质受热时，其粒子获得能量，可能引发状态变化：熔化（固态到液态）、沸腾或蒸发（液态到气态）、凝结（气态到液态）和凝固（液态到固态）。升华指固体直接转变为气体，例如固体二氧化碳（干冰）。
3. Physical and Chemical Changes | 物理变化与化学变化
A physical change does not produce any new substances. The change is often reversible and involves changes in state, shape or form. Examples include melting ice, dissolving salt in water and cutting paper. The key feature is that no new chemical bonds are formed or broken.
物理变化不产生任何新物质。这种变化通常是可逆的，涉及状态、形状或形态的改变。例子包括冰的融化、食盐溶于水和剪纸。关键特征是没有任何新的化学键形成或断裂。
A chemical change results in the formation of one or more new substances. It is usually difficult or impossible to reverse. Signs of a chemical reaction include colour change, temperature change, bubbles of gas appearing (effervescence), a precipitate forming or light being produced. Burning magnesium, rusting iron and cooking an egg are all chemical changes.
化学变化会生成一种或多种新物质。这种变化通常很难或无法逆转。化学反应的标志包括颜色改变、温度变化、产生气泡（冒泡）、生成沉淀或发光。镁条燃烧、铁生锈和煮鸡蛋都属于化学变化。
4. Elements, Compounds and Mixtures | 元素、化合物和混合物
An element is a substance that consists of only one type of atom. Elements cannot be broken down into simpler substances by chemical methods. Examples include oxygen (O), iron (Fe) and gold (Au). All elements are listed in the periodic table.
元素是仅由一种类型的原子组成的物质。元素无法通过化学方法分解成更简单的物质。例子包括氧 (O)、铁 (Fe) 和金 (Au)。所有元素都列在周期表中。
A compound is a substance made from two or more different elements chemically bonded together in fixed proportions. The properties of a compound are different from the elements it contains. Water (H₂O) is a compound of hydrogen and oxygen; carbon dioxide (CO₂) is a compound of carbon and oxygen. Compounds can only be separated into their elements by chemical reactions.
化合物是由两种或多种不同元素以固定比例通过化学键结合而成的物质。化合物的性质与其组成元素不同。水 (H₂O) 是氢和氧的化合物；二氧化碳 (CO₂) 是碳和氧的化合物。化合物只能通过化学反应分解成其组成元素。
A mixture contains two or more substances that are not chemically combined. Each substance keeps its own properties. Mixtures can be separated by physical methods such as filtration, evaporation or chromatography. Air and sea water are common examples of mixtures.
混合物包含两种或多种未发生化学结合的物质。每种物质保持其自身性质。混合物可通过物理方法分离，如过滤、蒸发或色谱法。空气和海水是混合物的常见例子。
5. Atoms and the Periodic Table | 原子与周期表
Atoms are the smallest particles of an element that still have the properties of that element. Every atom contains a tiny nucleus surrounded by electrons. The nucleus contains protons and neutrons. All atoms of the same element have the same number of protons, which is called the atomic number.
原子是元素中仍保留该元素性质的最小粒子。每个原子都有一个微小的原子核，周围有电子环绕。原子核包含质子和中子。同种元素的所有原子具有相同数量的质子，这个数目称为原子序数。
The periodic table arranges all elements in order of increasing atomic number. Elements are placed in rows called periods and columns called groups. Elements in the same group have similar chemical properties. Metals are found on the left side and in the centre, while non-metals are on the right. You should become familiar with the symbols of common elements such as: hydrogen (H), helium (He), carbon (C), nitrogen (N), oxygen (O), sodium (Na), magnesium (Mg), aluminium (Al), silicon (Si), phosphorus (P), sulfur (S), chlorine (Cl), potassium (K), calcium (Ca), iron (Fe), copper (Cu), zinc (Zn) and silver (Ag).
周期表将所有元素按原子序数递增的顺序排列。元素被排成行（称为周期）和列（称为族）。同一族的元素具有相似的化学性质。金属位于周期表的左侧和中间，而非金属位于右侧。你需要熟悉常见元素的符号，例如：氢 (H)、氦 (He)、碳 (C)、氮 (N)、氧 (O)、钠 (Na)、镁 (Mg)、铝 (Al)、硅 (Si)、磷 (P)、硫 (S)、氯 (Cl)、钾 (K)、钙 (Ca)、铁 (Fe)、铜 (Cu)、锌 (Zn) 和银 (Ag)。
6. Chemical Reactions and Word Equations | 化学反应与字方程式
A chemical reaction involves the rearrangement of atoms to make new substances. The starting materials are called reactants, and the new substances formed are called products. We can represent a reaction using a word equation: reactant + reactant → product (+ product) hen magnesium burns in oxygen, the word equation is: magnesium + oxygen → magnesium oxide.
化学反应涉及原子的重新排列，从而生成新物质。起始物质称为反应物，生成的新物质称为产物。我们可以用字方程式来表示反应：反应物 + 反应物 → 产物（+ 产物）。例如，镁在氧气中燃烧的字方程式为：镁 + 氧气 → 氧化镁。
acid → calcium chloride + water + carbon dioxide; and zinc + hydrochloric acid → zinc chloride + hydrogen. During any chemical reaction, the total mass remains the same; atoms are conserved.
Year 7 中其他常见的字方程式包括：甲烷 + 氧气 → 二氧化碳 + 水（完全燃烧）；碳酸钙 + 盐酸 → 氯化钙 + 水 + 二氧化碳；以及锌 + 盐酸 → 氯化锌 + 氢气。在任何化学反应过程中，总质量保持不变；原子是守恒的。
7. Acids and Alkalis | 酸和碱
Acids are substances that have a sour taste (but never taste them in the lab!) and can be corrosive. Common laboratory acids include hydrochloric acid (HCl), sulfuric acid (H₂SO₄) and nitric acid (HNO₃). Acids release hydrogen ions (H⁺) when dissolved in water.
酸是具有酸味（但绝不能在实验室品尝！）并可能具有腐蚀性的物质。常见的实验室酸包括盐酸 (HCl)、硫酸 (H₂SO₄) 和硝酸 (HNO₃)。酸溶于水时会释放氢离子 (H⁺)。
Alkalis are soluble bases that feel soapy and can also be corrosive. They release hydroxide ions (OH⁻) in water. Common alkalis include sodium hydroxide (NaOH), potassium hydroxide (KOH) and calcium hydroxide (Ca(OH)₂). Many household cleaners contain alkalis.
碱是可溶的碱性物质，摸起来有滑腻感，也可能具有腐蚀性。它们在水中释放氢氧根离子 (OH⁻)。常见的碱包括氢氧化钠 (NaOH)、氢氧化钾 (KOH) 和氢氧化钙 (Ca(OH)₂)。许多家用清洁剂含有碱性物质。
8. The pH Scale and Neutralisation | pH 标度与中和
The pH scale measures how acidic or alkaline a solution is. It ranges from 0 to 14: values less than 7 are acidic, 7 is neutral, and values greater than 7 are alkaline. We use indicators, such as litmus paper, universal indicator and phenolphthalein, to estimate the pH. Universal indicator turns red in strongly acidic solutions, green in neutral and purple in strongly alkaline solutions.
pH 标度用于衡量溶液的酸碱性强弱，范围从 0 到 14：小于 7 为酸性，等于 7 为中性，大于 7 为碱性。我们使用指示剂，如石蕊试纸、通用指示剂和酚酞，来估计 pH 值。通用指示剂在强酸性溶液中呈红色，中性时呈绿色，强碱性时呈紫色。
r example, hydrochloric acid + sodium hydroxide → sodium chloride + water. Neutralisation is used in agriculture to treat acidic soils and in medicine to relieve indigestion.
中和是酸与碱反应生成盐和水的过程。一般字方程式为：酸 + 碱 → 盐 + 水。例如，盐酸 + 氢氧化钠 → 氯化钠 + 水。中和方法在农业中用于改良酸性土壤，在医学上用于缓解消化不良。
9. Separation Techniques: Filtration and Evaporation | 分离技术：过滤与蒸发
Filtration is used to separate an insoluble solid from a liquid. The mixture is poured through filter paper in a funnel. The solid particles are trapped as a residue on the filter paper, while the liquid (the filtrate) passes through. Sand and water can be separated this way.
过滤用于分离不溶性固体和液体。混合物被倒入漏斗中的滤纸上。固体颗粒作为残渣被截留在滤纸上，而液体（滤液）则通过滤纸。沙子和水可以用这种方法分离。
Evaporation is used to obtain a soluble solid from a solution. The solution is heated gently so that the solvent (usually water) evaporates, leaving the solid behind. For example, heating a salt solution causes the water to evaporate, leaving salt crystals. This method works well for substances like sodium chloride that do not decompose on heating.
蒸发用于从溶液中获取可溶性固体。溶液被缓慢加热，使溶剂（通常是水）蒸发，留下固体。例如，加热食盐溶液使水蒸发，留下食盐晶体。这种方法适用于像氯化钠这样加热不分解的物质。
10. Chromatography and Simple Distillation | 色谱法与简单蒸馏
Chromatography is used to separate mixtures of coloured substances, such as inks or food dyes. A spot of the mixture is placed on chromatography paper and dipped into a solvent. As the solvent moves up, the different components travel at different speeds, producing separated spots. This allows us to identify them by their retention factors (Rf values) and to check purity.
色谱法用于分离有色物质的混合物，如墨水或食用色素。将一滴混合物点在色谱纸上，并浸入溶剂中。随着溶剂向上移动，不同组分以不同速度移动，形成分离的色斑。这使我们能够通过它们的比移值 (Rf 值) 来鉴定物质，并检查纯度。
Simple distillation separates a pure liquid from a solution. The solution is heated until the liquid boils. The vapour passes into a condenser where it is cooled and turned back into a liquid (distillate), which is collected. The dissolved solid remains in the flask. This method is used to obtain pure water from salt water.
简单蒸馏用于从溶液中分离出纯净液体。将溶液加热至液体沸腾，蒸气进入冷凝管冷却后变回液体（馏出液），并被收集起来。溶解的固体留在烧瓶中。这种方法可用于从盐水中制取纯水。
11. Metals and Non-metals | 金属与非金属
Elements are broadly divided into metals and non-metals. Metals are usually shiny, hard (except mercury), malleable (can be hammered into shape), ductile (can be drawn into wires) and good conductors of heat and electricity. Examples include copper, iron and aluminium. Non-metals are often dull, brittle (if solid), and poor conductors of heat and electricity (except graphite, a form of carbon). Typical non-metals are oxygen, sulfur and chlorine.
元素大致分为金属和非金属。金属通常有光泽、坚硬（汞除外）、有延展性（能锤打成形状）、有韧性（可拉成丝），并且是热和电的良导体。例子包括铜、铁和铝。非金属通常黯淡无光、脆（如果是固体），且是热和电的不良导体（石墨除外，它是碳的一种形式）。典型的非金属有氧、硫和氯。
e + hydrogen. Metals also react with oxygen to form metal oxides; this is an oxidation reaction. Non-metals such as carbon and sulfur burn in oxygen to form acidic oxides like carbon dioxide and sulfur dioxide.
许多金属与酸反应生成盐和氢气。例如，锌 + 硫酸 → 硫酸锌 + 氢气。金属还与氧气反应生成金属氧化物，属于氧化反应。非金属如碳和硫在氧气中燃烧会生成酸性氧化物，如二氧化碳和二氧化硫。
Published by TutorHao | Chemistry Revision Series | aleveler.com
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