📚 Year 7 SQA Chemistry: Core Knowledge Review | Year 7 SQA 化学：核心知识点梳理
Welcome to your comprehensive review of Year 7 Chemistry under the Scottish Curriculum for Excellence (SQA). This guide covers the essential topics you will encounter at S1 level, including the particle model, elements and compounds, simple chemical reactions, acids and alkalis, and practical separation techniques. Let us build a strong foundation for your scientific journey.
欢迎来到 Year 7 SQA 化学核心知识点梳理。本指南依据苏格兰卓越课程（SQA）编写，涵盖 S1 阶段所学的关键内容：粒子模型、元素与化合物、基础化学反应、酸碱以及常用的分离方法。让我们一起为科学学习打下扎实的基础。
1. The Particle Model | 粒子模型
All substances are made up of extremely tiny particles that are in constant motion. The way these particles are arranged and how they move determines the state of the matter – solid, liquid or gas.
所有物质都由极其微小且不断运动的粒子构成。粒子的排列方式和运动状态决定了物质是固体、液体还是气体。
In a solid, particles are packed closely together in a fixed, regular pattern. They can only vibrate in their positions, which gives solids a definite shape and a fixed volume.
在固体中，粒子紧密排列成固定的规则结构，只能在自己的位置上振动，因此固体有确定的形状和固定的体积。
In a liquid, particles are still close together but are not held in a rigid pattern. They can slide past each other, so liquids have a fixed volume but no fixed shape – they take the shape of the bottom of their container.
在液体中，粒子仍然彼此靠近，但没有刚性结构。它们能够相互滑动，因此液体有固定的体积但没有固定的形状——它们会随容器底部改变形状。
In a gas, particles are far apart and move rapidly in all directions. Gases have no fixed shape and no fixed volume; they spread out to fill any space available.
在气体中，粒子相距很远，并向各个方向高速运动。气体没有固定的形状和体积，会扩散并充满整个可用空间。
2. Changes of State | 状态变化
Matter can change from one state to another when heat energy is added or removed. The main changes of state are melting (solid to liquid), freezing (liquid to solid), boiling/evaporation (liquid to gas), condensation (gas to liquid) and sublimation (solid directly to gas).
当热量被吸收或释放时，物质会从一种状态转变为另一种状态。主要的状态变化包括熔化（固态→液态）、凝固（液态→固态）、沸腾/蒸发（液态→气态）、冷凝（气态→液态）和升华（固态直接变为气态）。
During a change of state, the temperature of the substance does not change until the change is complete. For example, when ice melts, its temperature stays at 0 °C until all the ice has turned into water.
在状态变化过程中，物质的温度在变化完成之前保持不变。例如，冰融化时温度停留在 0 °C，直到所有冰都变成水。
Evaporation is different from boiling: evaporation happens only at the surface of a liquid and can occur at any temperature, while boiling occurs throughout the liquid at a specific temperature called the boiling point.
蒸发与沸腾不同：蒸发只发生在液体表面，可以在任何温度下进行；而沸腾在整个液体内部发生，需要达到特定的温度，即沸点。
3. Elements, Compounds and Mixtures | 元素、化合物与混合物
An element is a pure substance made up of only one type of atom. All atoms of a given element have the same number of protons. Examples include oxygen (O), iron (Fe) and gold (Au).
元素是由同种原子组成的纯物质。同种元素的所有原子具有相同的质子数。例如氧（O）、铁（Fe）和金（Au）。
A compound is a pure substance formed when two or more different elements are chemically bonded together in a fixed ratio. A compound has properties very different from the elements it contains. Water (H₂O) and carbon dioxide (CO₂) are common compounds.
化合物是两种或多种不同元素按照固定比例通过化学键结合而成的纯物质。化合物的性质与组成它的元素性质大不相同。水（H₂O）和二氧化碳（CO₂）是常见的化合物。
A mixture consists of two or more substances (elements or compounds) that are physically combined but not chemically bonded. The components in a mixture keep their own properties and can be separated by physical methods such as filtration or distillation. Air is a mixture of gases.
混合物由两种或多种物质（元素或化合物）物理混合而成，各组分之间没有化学键。混合物中各组分会保持自身性质，可通过过滤或蒸馏等物理方法分离。空气就是一种气体混合物。
4. The Periodic Table | 元素周期表
The Periodic Table is a chart that organises all known elements in order of increasing atomic number. Elements are arranged in rows called periods and columns called groups. Elements in the same group have similar chemical properties because they have the same number of electrons in their outermost shell.
元素周期表是一种将所有已知元素按原子序数递增顺序排列的图表。元素排成横行（周期）和纵列（族）。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。
Metals are found on the left side and in the centre of the Periodic Table; they are usually shiny, good conductors of heat and electricity, and can be hammered into shape. Non-metals are on the right side; they are often dull and poor conductors. A zig-zag line separates the two groups.
金属位于周期表左侧和中部；它们通常有光泽，是热和电的良导体，可被锤打成形。非金属位于右侧，通常暗淡无光，导电导热性能差。一条锯齿形斜线将金属和非金属分开。
5. Chemical Reactions | 化学反应
A chemical reaction is a process where substances (reactants) are changed into new substances (products). Signs of a chemical reaction include a colour change, temperature change, gas being given off (bubbles) or a precipitate (solid) forming.
化学反应是物质（反应物）转变为新物质（生成物）的过程。发生化学反应的迹象包括颜色变化、温度变化、气体（气泡）放出或沉淀（固体）生成。
ns using word equations: reactant + reactant → product. For example, magnesium + oxygen → magnesium oxide.
在化学反应中，原子发生了重新组合，但原子既未被创造也未被消灭，这就是质量守恒定律。我们可以用文字方程式表示反应：反应物 + 反应物 → 生成物。例如：镁 + 氧气 → 氧化镁。
Physical changes, like melting or dissolving sugar in water, are not chemical reactions because no new substances are made and the process is usually reversible without breaking chemical bonds.
物理变化，例如熔化或将糖溶于水，不属于化学反应，因为没有新物质生成，且过程通常可逆，不需要破坏化学键。
6. Acids and Alkalis | 酸和碱
Acids are substances that release hydrogen ions (H⁺) when dissolved in water. They have a sour taste, turn blue litmus paper red, and have a pH less than 7. Common laboratory acids include hydrochloric acid and sulfuric acid.
酸是溶于水时释放氢离子（H⁺）的物质。它们有酸味，能使蓝色石蕊试纸变红，pH 值小于 7。实验室常见的酸有盐酸和硫酸。
Alkalis are soluble bases that release hydroxide ions (OH⁻) in water. They feel soapy, turn red litmus paper blue, and have a pH greater than 7. Sodium hydroxide and potassium hydroxide are typical alkalis.
碱是可溶性碱类，在水中释放氢氧根离子（OH⁻）。它们有滑腻感，能使红色石蕊试纸变蓝，pH 值大于 7。氢氧化钠和氢氧化钾是典型的碱。
The pH scale goes from 0 to 14 and measures how acidic or alkaline a solution is. A neutral substance (pH 7) is neither acidic nor alkaline – pure water is neutral. Universal indicator turns different colours across the pH range, from red in strong acid to purple in strong alkali.
pH 标度范围为 0 至 14，衡量溶液的酸碱度。中性物质（pH = 7）既非酸性也非碱性——纯水就是中性。通用指示剂在不同 pH 值下显示不同颜色，强酸中呈红色，强碱中呈紫色。
ter. This reaction is very useful in treating acid spills and in making everyday products.
酸与碱反应生成盐和水的反应称为中和反应。通用的文字方程式是：酸 + 碱 → 盐 + 水。中和反应在处理酸泄漏以及制造日常用品中非常有用。
7. Separation Techniques | 分离技术
Chemists use several techniques to separate mixtures into their components. The choice of method depends on the physical properties of the substances in the mixture, such as particle size, boiling point or solubility.
化学家使用多种技术将混合物分离为各组分。方法的选择取决于混合物中物质的物理性质，如粒径、沸点或溶解度。
Filtration is used to separate an insoluble solid from a liquid. The mixture is poured through filter paper; the solid stays on the paper (the residue) and the liquid passes through (the filtrate).
过滤用于分离不溶性固体和液体。混合物倒入滤纸，固体留在滤纸上（称为残渣），液体通过滤纸（称为滤液）。
Evaporation and crystallisation can separate a soluble solid from a solution. By heating the solution, the solvent evaporates and leaves the solid behind. If we evaporate slowly, larger crystals can form.
蒸发和结晶可用于从溶液中分离可溶性固体。加热溶液时，溶剂蒸发留下固体。如果缓慢蒸发，可得到较大的晶体。
Distillation separates a solvent from a solution by boiling the liquid and then condensing the vapour back into a liquid in a different container. It allows us to obtain pure water from salt water.
蒸馏是通过煮沸液体然后将蒸气冷凝到另一容器中来分离溶剂和溶液的方法。利用蒸馏可以从盐水中获得纯水。
Chromatography can separate mixtures of dissolved coloured substances, such as inks. As the solvent moves up the chromatography paper, different substances travel at different speeds, allowing them to be seen as separate spots.
色谱法可以分离溶解的有色物质混合物，例如墨水。当溶剂沿着色谱纸向上移动时，不同物质以不同速度移动，从而形成独立的色斑。
8. Earth's Atmosphere and Combustion | 地球大气与燃烧
The Earth's atmosphere today is composed mainly of nitrogen (about 78%) and oxygen (about 21%), with small amounts of argon, carbon dioxide and water vapour. This composition supports life and is essential for combustion and respiration.
今天的地球大气主要由氮气（约 78%）和氧气（约 21%）组成，还有少量氩气、二氧化碳和水蒸气。这一组成维持着生命，也是燃烧和呼吸所必需的。
Combustion is a chemical reaction in which a fuel reacts with oxygen to release energy as heat and light. For burning to happen, three things are needed: a fuel, oxygen and heat (the fire triangle). Removing any one of these extinguishes the fire.
燃烧是燃料与氧气发生反应并以热和光的形式释放能量的化学过程。燃烧发生需要三个条件：燃料、氧气和热量（即火三角）。移去任何一项，火就会熄灭。
Complete combustion of a hydrocarbon fuel produces carbon dioxide and water vapour. Incomplete combustion occurs when the oxygen supply is limited, producing carbon monoxide (a toxic gas) and carbon (soot).
碳氢燃料的完全燃烧生成二氧化碳和水蒸气。当氧气不足时发生不完全燃烧，会生成一氧化碳（一种有毒气体）和碳（黑烟灰）。
Fossil fuels like coal, oil and natural gas are non-renewable resources. Burning them releases carbon dioxide, a greenhouse gas that contributes to global warming.
煤、石油和天然气等化石燃料是不可再生资源。燃烧它们会释放二氧化碳，这是一种导致全球变暖的温室气体。
9. Pure and Impure Substances | 纯净物与不纯物
In chemistry, a pure substance contains only one type of element or compound and has fixed melting and boiling points. For example, pure water melts at exactly 0 °C and boils at exactly 100 °C at standard pressure.
在化学中，纯净物只含一种元素或化合物，具有固定的熔点和沸点。例如，纯水在标准大气压下准确地在 0 °C 熔化和 100 °C 沸腾。
An impure substance is a mixture. Impurities lower the melting point and raise the boiling point of a substance. The greater the amount of impurity, the bigger the change, and the substance melts or boils over a range of temperatures rather than at a single point.
不纯物就是混合物。杂质会降低物质的熔点并提高沸点。杂质越多，温度改变越大，且物质会在一个温度区间内熔化或沸腾，而不是在一个精确的温度点。
We can use melting and boiling points to check the purity of a sample. A sample that melts sharply at the expected temperature is likely very pure; if it melts over a wide range, it contains impurities.
我们可以利用熔点和沸点来检验样品的纯度。若样品在预期温度下急剧熔化，很可能非常纯净；若在一个较宽的范围内熔化，则含有杂质。
10. Chemistry in Everyday Life | 生活中的化学
Chemistry is not just in the laboratory – it is everywhere in our daily lives. Baking soda (sodium hydrogen carbonate) is an alkali used in baking; when heated, it releases carbon dioxide gas, helping cakes rise.
化学不仅存在于实验室，也贯穿于我们的日常生活。小苏打（碳酸氢钠）是一种用于烘焙的碱；加热时会放出二氧化碳气体，帮助蛋糕膨胀。
Vinegar contains ethanoic acid, a weak acid used in food preparation and as a natural cleaning agent. Lemon juice contains citric acid, while many household cleaning products contain alkalis to dissolve grease.
食醋中含有乙酸，是一种用于食物调味和天然清洁的弱酸。柠檬汁含有柠檬酸，而许多家用清洁剂含有碱性物质以溶解油脂。
Fermentation is a chemical process where microorganisms like yeast convert sugar into ethanol and carbon dioxide. This reaction is used to make bread and alcoholic drinks.
发酵是利用酵母等微生物将糖转化为乙醇和二氧化碳的化学过程。这种反应被用于制作面包和酒精饮料。
Understanding the chemistry of everyday materials helps us use them safely and sustainably – for example, avoiding mixing certain cleaning products that could release harmful gases.
理解日常材料的化学性质有助于我们安全、可持续地使用它们——例如，避免混合可能释放有害气体的某些清洁产品。
Published by TutorHao | Chemistry Revision Series | aleveler.com
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