Complete Chemistry for Cambridge Secondary Workbook | 剑桥初中化学练习册全攻略

📚 Complete Chemistry for Cambridge Secondary Workbook | 剑桥初中化学练习册全攻略

This article summarises the essential topics in the CIE Complete Chemistry for Cambridge Secondary Workbook. It is designed for students preparing for Cambridge Checkpoint or secondary chemistry assessments. The content covers key concepts, common equations and practical skills that often appear in exam papers.

本文总结 CIE 剑桥初中化学练习册的核心主题，适合准备剑桥 Checkpoint 或初中化学考试的学生复习使用。内容涵盖常考的核心概念、常见方程式和实验技能。

1. States of Matter | 物质的状态

Matter exists in three main states: solid, liquid and gas. The state depends on the arrangement and movement of particles. Changes between these states are known as physical changes because no new substance is formed.

物质主要以三种状态存在：固态、液态和气态。状态取决于粒子的排列方式和运动情况。这些状态之间的变化称为物理变化，因为没有新物质生成。

In solids, particles are closely packed in a regular pattern and vibrate in fixed positions. In liquids, particles are close together but can slide past each other, so liquids can flow and take the shape of their container. In gases, particles are far apart and move rapidly in all directions, so gases spread out to fill the whole container.

在固态中，粒子紧密排列成规则结构，并在固定位置振动；在液态中，粒子靠近但能相互滑动，因此液体可以流动并呈现容器的形状；在气态中，粒子相距很远并朝各个方向快速运动，因此气体会扩散并充满整个容器。

Changes of state include melting, freezing, evaporation, condensation and sublimation. For example, ice melts to water at 0 °C, and water boils to steam at 100 °C under normal atmospheric pressure.

状态变化包括熔化、凝固、蒸发、冷凝和升华。例如，在标准大气压下，冰在 0 °C 熔化成水，水在 100 °C 沸腾变成水蒸气。

Heating a substance gives particles more kinetic energy. During melting and boiling, the temperature stays constant even though energy is still being supplied. This energy is used to overcome the forces between particles rather than to raise the temperature.

加热物质会使粒子获得更多动能。在熔化和沸腾过程中，尽管持续供热，温度却保持不变。这些能量用于克服粒子之间的作用力，而不是用于升温。

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2. Particle Theory and Diffusion | 粒子理论与扩散

The particle theory states that all matter is made of tiny particles that are always moving. Heating increases particle energy and makes them move faster. This explains expansion, diffusion and changes of state.

粒子理论指出，所有物质都由不断运动的微小粒子组成。加热会增加粒子能量，使它们运动得更快。这可以解释膨胀、扩散和状态变化等现象。

Diffusion is the movement of particles from a region of higher concentration to a region of lower concentration. It occurs faster in gases than in liquids because gas particles move more quickly and have larger spaces between them.

扩散是粒子从高浓度区域向低浓度区域的运动。扩散在气体中比在液体中更快，因为气体粒子运动得更快，粒子之间的空隙更大。

For example, a drop of ink spreads through water, and the smell of perfume travels across a room. Diffusion is also important in living organisms, such as oxygen moving into cells.

例如，一滴墨水会在水中扩散，香水的味道会飘满整个房间。扩散在生物体中也十分重要，例如氧气进入细胞的过程。

The rate of diffusion increases with temperature because particles gain more kinetic energy. Smaller and lighter particles diffuse faster than larger and heavier particles at the same temperature.

扩散速率随温度升高而增大，因为粒子获得更多动能。在相同温度下，较小、较轻的粒子比较大、较重的粒子扩散得更快。

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3. 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. Atoms contain protons, neutrons and electrons. Protons have a positive charge, electrons have a negative charge, and neutrons have no charge.

原子是元素中能参与化学反应的最小粒子。原子由质子、中子和电子组成。质子带正电荷，电子带负电荷，中子不带电荷。

An element is a pure substance made of only one type of atom. A compound is a substance made of two or more different elements chemically joined together. Compounds have properties that are different from the elements they are made from.

元素是只由一种原子组成的纯净物。化合物是由两种或多种不同元素通过化学键结合而成的物质。化合物的性质与组成它的元素不同。

For example, oxygen (O₂) is an element, while water (H₂O) and carbon dioxide (CO₂) are compounds. A mixture contains different substances that are not chemically joined and can be separated by physical methods.

例如，氧气 (O₂) 是元素，而水 (H₂O) 和二氧化碳 (CO₂) 是化合物。混合物含有不同物质，它们没有通过化学键结合，可以用物理方法分离。

The atomic number is the number of protons in an atom. The mass number is the total number of protons and neutrons. In a neutral atom, the number of protons equals the number of electrons.

原子序数是原子中质子的数目。质量数是质子和中子的总数。在中性原子中，质子数等于电子数。

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4. The Periodic Table | 元素周期表

The periodic table arranges elements in order of increasing atomic number. Elements in the same group have similar chemical properties because they have the same number of electrons in their outer shell.

元素周期表按原子序数递增的顺序排列元素。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 metals are called alkali metals. They are reactive and react vigorously with water to form alkaline solutions and hydrogen gas. For example, sodium reacts with water to form sodium hydroxide and hydrogen.

第1族金属称为碱金属。它们很活泼，与水剧烈反应生成碱性溶液和氢气。例如，钠与水反应生成氢氧化钠和氢气。

Group 7 elements are called halogens. They are reactive non-metals with coloured vapours. Group 0 elements are called noble gases and are very unreactive because they have a full outer shell of electrons.

第7族元素称为卤素，是活泼的非金属，具有有颜色的蒸气。第0族元素称为稀有气体，非常不活泼，因为它们的最外层电子已经排满。

Metals are found on the left of the periodic table, and non-metals on the right. The zig-zag line separates metals from non-metals. Elements near this line, such as silicon, are called metalloids and have properties of both metals and non-metals.

金属位于周期表左侧，非金属位于右侧。锯齿线将金属和非金属分开。靠近这条线的元素，例如硅，称为类金属，同时具有金属和非金属的性质。

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5. Chemical Bonding Basics | 化学键基础

Atoms bond together to achieve a full outer shell of electrons, which makes them stable. The two main types of bonding are ionic and covalent. The type of bonding depends on the elements involved.

原子通过结合达到最外层电子满壳层，从而变得稳定。两种主要键型是离子键和共价键。键型取决于参与结合的元素。

Ionic bonding occurs between metals and non-metals. Electrons are transferred from the metal to the non-metal, forming positive and negative ions. The electrostatic attraction between oppositely charged ions holds the compound together.

离子键发生在金属和非金属之间。电子从金属转移到非金属，形成正离子和负离子。带相反电荷的离子之间的静电引力使化合物保持在一起。

Covalent bonding occurs between non-metal atoms. Electrons are shared between atoms to fill their outer shells. A molecule is a group of atoms held together by covalent bonds.

共价键发生在非金属原子之间。电子在原子之间共享，以填满最外层。分子是由共价键结合在一起的一组原子。

For example, sodium chloride (NaCl) has ionic bonding, while water (H₂O) and methane (CH₄) have covalent bonding. Ionic compounds often have high melting points, while simple covalent molecules usually have low melting points.

例如，氯化钠 (NaCl) 具有离子键，而水 (H₂O) 和甲烷 (CH₄) 具有共价键。离子化合物通常熔点较高，而简单共价分子通常熔点较低。

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6. Writing Chemical Equations | 书写化学方程式

A chemical equation shows the reactants and products in a reaction. The number of atoms of each element must be the same on both sides because mass is conserved in a chemical reaction.

化学方程式表示反应中的反应物和生成物。每种元素的原子数在两边必须相同，因为化学反应中质量守恒。

For example, the reaction between hydrogen and oxygen to form water is written as:

例如，氢气与氧气反应生成水的方程式写为：

2H₂ + O₂ → 2H₂O

State symbols are often added: (s) for solid, (l) for liquid, (g) for gas and (aq) for aqueous solution. For example, the complete equation for the reaction of magnesium with hydrochloric acid is:

通常还加上状态符号：(s) 表示固态，(l) 表示液态，(g) 表示气态，(aq) 表示水溶液。例如，镁与盐酸反应的完整方程式为：

Mg(s) + 2HCl(aq) → MgCl₂(aq) + H₂(g)

Balancing equations is an important skill. Start by counting the atoms of each element on both sides, then add coefficients in front of the formulas until the numbers are equal.

配平方程式是一项重要技能。先数出两边每种元素的原子数，然后在化学式前添加系数，直到两边原子数相等。

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7. Acids, Bases and Indicators | 酸、碱与指示剂

Acids are substances that release hydrogen ions (H⁺) in water. Common acids include hydrochloric acid (HCl), sulfuric acid (H₂SO₄) and nitric acid (HNO₃).

酸是在水中释放氢离子 (H⁺) 的物质。常见的酸包括盐酸 (HCl)、硫酸 (H₂SO₄) 和硝酸 (HNO₃)。

Bases are substances that neutralise acids. Alkalis are bases that dissolve in water and release hydroxide ions (OH⁻). Common alkalis include sodium hydroxide (NaOH) and potassium hydroxide (KOH).

碱是能中和酸的物质。可溶于水的碱称为可溶性碱，它们在水中释放氢氧根离子 (OH⁻)。常见的碱包括氢氧化钠 (NaOH) 和氢氧化钾 (KOH)。

Indicators change colour in acidic or alkaline solutions. Litmus turns red in acid and blue in alkali. Universal indicator shows a range of colours depending on pH, from red for strongly acidic to purple for strongly alkaline.

指示剂在酸性或碱性溶液中会变色。石蕊在酸中变红，在碱中变蓝。通用指示剂根据 pH 显示不同颜色，从强酸性的红色到强碱性的紫色

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