📚 IB OCR Chemistry: Final Term Revision Guide | IB OCR 化学：期末复习提纲
This revision guide is designed to help you consolidate the major themes in IB and OCR Chemistry courses. It covers atomic structure, bonding, energetics, kinetics, equilibrium, acids & bases, redox, and organic chemistry. Use it as a checklist to identify key knowledge points, equations, and typical examination questions before your end-of-term assessment.
本复习提纲旨在帮助你巩固 IB 和 OCR 化学课程中的核心主题。内容涵盖原子结构、化学键、能量学、动力学、平衡、酸碱、氧化还原以及有机化学。你可以把它当作一份清单，用于在期末考试前查漏补缺，回顾重要知识点、方程式和常见考题类型。
1. Atomic Structure and Electron Configuration | 原子结构与电子排布
The atom consists of a nucleus containing protons and neutrons, surrounded by electrons arranged in energy levels (shells) and sublevels (subshells). For IB and OCR, you must be able to write electron configurations using s, p, d notation and understand orbital diagrams.
原子由包含质子和中子的原子核以及核外分层排布的电子构成。在 IB 和 OCR 考试中，你需要能用 s、p、d 符号书写电子排布式，并理解轨道示意图。
Remember the order of filling: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, etc. Exceptions such as chromium (Cr) and copper (Cu) arise due to the extra stability of half-filled and fully filled d-subshells.
记住填充顺序：1s、2s、2p、3s、3p、4s、3d、4p 等。铬（Cr）和铜（Cu）等例外情况是由于半满和全满 d 亚层额外稳定性导致的。
First ionisation energy is the energy required to remove one mole of electrons from one mole of gaseous atoms. Trends across a period increase due to greater nuclear charge and similar shielding; trends down a group decrease with increased atomic radius and shielding.
第一电离能是指从气态原子中移除一摩尔电子所需的能量。同一周期从左到右，核电荷增加而屏蔽效应相似，电离能总体升高；同一族从上到下，原子半径和屏蔽效应增大，电离能降低。
Mass spectrometry data can be used to determine the relative atomic mass of an element from isotopic abundances. The equation is: Aᵣ = Σ (isotopic mass × % abundance) / 100.
质谱数据可用于根据同位素丰度计算元素的相对原子质量。计算公式为：Aᵣ = Σ (同位素质量 × 丰度%) / 100。
2. Periodicity and Trends | 周期性与元素周期律
The periodic table is arranged by increasing atomic number. Elements in the same group have the same number of outer electrons, leading to similar chemical properties. Period 3 elements (Na to Ar) are particularly important for OCR and IB comparison of properties.
元素周期表按原子序数递增排列。同一主族元素具有相同的外层电子数，因此化学性质相似。第 3 周期元素（Na 至 Ar）在 OCR 和 IB 考试中常用于比较性质。
Atomic radius decreases across a period and increases down a group. Ionic radius follows similar trends, but cations are smaller than parent atoms while anions are larger. Melting points for Period 3 rise from Na to Si (giant structures), then drop sharply for simple molecular P₄, S₈, Cl₂, and remain low for Ar.
原子半径在同一周期内递减，同一族内递增。离子半径规律类似，但阳离子比母体原子小，阴离子更大。第 3 周期熔点从 Na 到 Si 上升（巨型结构），然后对简单分子 P₄、S₈、Cl₂ 急剧下降，Ar 保持很低。
Electronegativity increases across a period and decreases down a group. You should be able to predict bond polarity using electronegativity values. Oxides of Period 3 show clear trends from basic (Na₂O, MgO) to amphoteric (Al₂O₃) to acidic (SiO₂, P₄O₁₀, SO₂, SO₃).
电负性在同一周期内递增，同一族内递减。应能使用电负性值预测键的极性。第 3 周期氧化物从碱性（Na₂O、MgO）到两性（Al₂O₃）再到酸性（SiO₂、P₄O₁₀、SO₂、SO₃）呈现清晰趋势。
3. Chemical Bonding and Structure | 化学键与结构
Ionic bonding occurs between metals and non-metals via electron transfer, forming a giant ionic lattice. Key properties include high melting point, brittleness, and electrical conductivity when molten or dissolved.
离子键通过电子转移在金属和非金属之间形成，构成巨型离子晶格。主要性质包括高熔点、脆性，以及在熔融或溶解状态下的导电性。
Covalent bonding involves sharing of electron pairs. Simple molecular substances (I₂, H₂O, CO₂) have low melting points and poor conductivity. Giant covalent structures (diamond, graphite, SiO₂) have very high melting points. Graphite conducts electricity due to delocalised electrons between layers.
共价键涉及电子对的共享。简单分子物质（I₂、H₂O、CO₂）熔点和沸点低，导电性差。巨型共价结构（金刚石、石墨、SiO₂）熔点极高。石墨因层间存在离域电子而导电。
Use VSEPR theory to predict shapes: linear (2 bond pairs), trigonal planar (3 bp), tetrahedral (4 bp), trigonal bipyramidal (5 bp), octahedral (6 bp). The presence of lone pairs distorts bond angles, for example NH₃ is trigonal pyramidal, H₂O is bent.
运用 VSEPR 理论预测分子形状：直线形（2 个成键电子对）、平面三角形（3 对）、四面体形（4 对）、三角双锥形（5 对）、八面体形（6 对）。孤对电子的存在会压缩键角，例如 NH₃ 为三角锥形，H₂O 为 V 形。
Metallic bonding is the attraction between metal cations and a sea of delocalised electrons. It explains malleability, ductility, and electrical conductivity. Alloys often have different properties due to disrupted lattice arrangements.
金属键是金属阳离子与离域电子海之间的吸引力。这可以解释金属的展性、延展性和导电性。合金由于晶格排列被扰乱，性质常发生变化。
4. Stoichiometry and the Mole Concept | 化学计量与摩尔概念
The mole links mass, number of particles, and volume of gases. Avogadro’s constant is 6.02 × 10²³ mol⁻¹. The equation n = m / M is fundamental for converting mass to moles.
摩尔将质量、粒子数和气体体积联系起来。阿伏伽德罗常数为 6.02 × 10²³ mol⁻¹。公式 n = m / M 是实现质量和摩尔数转换的基础。
Empirical formula is the simplest whole-number ratio of atoms in a compound; molecular formula gives the actual number. Combustion analysis data or percentage composition is often used to calculate these.
实验式是化合物中各元素原子的最简整数比；分子式则表示实际原子个数。常通过燃烧分析数据或元素质量分数来计算实验式和分子式。
Reacting mass calculations require a balanced equation. Determine the limiting reactant to find theoretical yield. Percentage yield = (actual yield / theoretical yield) × 100%. Atom economy = (molar mass of desired product / sum of molar masses of all products) × 100%.
反应质量计算需要配平方程式。通过确定限制反应物来求出理论产量。产率 = (实际产量 / 理论产量) × 100%。原子经济性 = (目标产物摩尔质量 / 所有产物摩尔质量总和) × 100%。
For gases, molar volume at RTP (room temperature and pressure) is approximately 24 dm³ mol⁻¹ or 24 000 cm³ mol⁻¹. Ideal gas equation pV = nRT may also be needed for non-standard conditions (R = 8.31 J K⁻¹ mol⁻¹).
对于气体，室温常压下的摩尔体积约为 24 dm³ mol⁻¹ 或 24 000 cm³ mol⁻¹。在非标准条件下可能需要使用理想气体状态方程 pV = nRT（R = 8.31 J K⁻¹ mol⁻¹）。
5. Energetics and Thermochemistry | 能量学与热化学
Enthalpy change (ΔH) is the heat energy transferred in a reaction at constant pressure. Exothermic reactions release energy (ΔH negative), endothermic reactions absorb energy (ΔH positive). Standard conditions are 100 kPa and 298 K.
焓变（ΔH）是恒压条件下反应吸收或放出的热量。放热反应释放能量（ΔH 为负），吸热反应吸收能量（ΔH 为正）。标准条件为 100 kPa 和 298 K。
Common enthalpy changes include: standard enthalpy of combustion (ΔH꜀⦵), standard enthalpy of formation (ΔH꜀⦵), and standard enthalpy of neutralisation (ΔH꜀ₙₑᵤₜ⦵). Use q = mcΔT for calorimetry experiments, where q is heat energy, m is mass, c is specific heat capacity, and ΔT is temperature change.
常见焓变包括：标准燃烧焓（ΔH꜀⦵）、标准生成焓（ΔH꜀⦵）和标准中和焓（ΔH꜀ₙₑᵤₜ⦵）。量热实验中使用 q = mcΔT，其中 q 为热量，m 为质量，c 为比热容，ΔT 为温度变化。
Hess’s Law states that the total enthalpy change for a reaction is independent of the route taken. Construct enthalpy cycles or use standard enthalpies of formation and combustion to calculate unknown ΔH values. Remember: ΔH reaction = ΣΔH꜀⦵(products) – ΣΔH꜀⦵(reactants).
赫斯定律指出，一个反应的总焓变与所经途径无关。可以构建焓循环或利用标准生成焓与燃烧焓来计算未知的 ΔH。记住：反应 ΔH = ΣΔH꜀⦵（产物）– ΣΔH꜀⦵（反应物）。
Average bond enthalpies can estimate ΔH, but they are less accurate because they are averages over many different molecules. ΔH = Σ(bond enthalpies of bonds broken) – Σ(bond enthalpies of bonds formed).
平均键焓可用于估算 ΔH，但准确性较低，因为它们是多种分子中的平均值。ΔH = Σ（断裂键的键焓）– Σ（形成键的键焓）。
6. Chemical Kinetics | 化学动力学
The rate of reaction is the change in concentration of a reactant or product per unit time. Factors affecting rate include concentration, pressure (for gases), temperature, surface area, and catalysts.
反应速率是指单位时间内反应物或生成物浓度的变化量。影响速率的因素有浓度、压强（对气体而言）、温度、表面积和催化剂。
Collision theory states that particles must collide with sufficient energy (activation energy, Eₐ) and correct orientation for a reaction to occur. The Maxwell–Boltzmann distribution shows the range of kinetic energies of particles; increasing temperature shifts the curve to higher energies and increases the fraction of particles with E ≥ Eₐ.
碰撞理论认为，粒子必须发生碰撞且能量不低于活化能（Eₐ）并取向合适，反应才能发生。麦克斯韦-玻尔兹曼分布曲线展示粒子动能分布；升高温度使曲线右移，增大能量不低于 Eₐ 的粒子比例。
For OCR and IB, you may encounter rate equations of the form: rate = k[A]ᵐ[B]ⁿ, where m and n are orders of reaction. The overall order is m + n. The rate constant k is only affected by temperature. Determine orders from initial rates data or concentration–time graphs.
在 OCR 和 IB 中，可能遇到速率方程形式如 rate = k[A]ᵐ[B]ⁿ，其中 m 和 n 为反应级数。总级数为 m + n。速率常数 k 仅受温度影响。需通过初始速率数据或浓度-时间图确定级数。
Mechanisms include rate-determining step. The species in the rate equation must appear in or before the slow step. Catalysts provide an alternative pathway with lower activation energy; they appear unchanged at the end of a reaction.
反应机理中包含决速步骤。速率方程中出现的物种必定出现在慢步骤或其前续步骤中。催化剂通过提供活化能较低的新路径起作用，反应结束后本身保持不变。
7. Chemical Equilibrium | 化学平衡
Dynamic equilibrium occurs in a closed system when the rate of the forward reaction equals the rate of the backward reaction. Concentrations of reactants and products remain constant, but reactions are still proceeding.
在封闭体系中，正反应速率与逆反应速率相等时达到动态平衡。反应物和产物的浓度保持不变，但正逆反应仍在进行。
Le Chatelier’s principle predicts the effect of changes in concentration, pressure, and temperature on the equilibrium position. Increasing concentration of a reactant shifts equilibrium to the product side. For gaseous reactions, increasing pressure favours the side with fewer moles of gas. For exothermic reactions, increasing temperature shifts equilibrium towards reactants.
勒夏特列原理可用于预测浓度、压强和温度变化对平衡位置的影响。增加反应物浓度使平衡向产物方向移动。对于气体反应，增加压强有利于气体分子总数较少的一侧。对于放热反应，升高温度使平衡向反应物方向移动。
Catalysts do not affect the equilibrium position; they only allow equilibrium to be reached more quickly. This is because they lower activation energy for both forward and backward reactions equally.
催化剂不影响平衡位置，只缩短达到平衡所需的时间，因为它同等程度降低正逆反应活化能。
The equilibrium constant K꜀ is expressed in terms of concentration. For aA + bB ⇌ cC + dD, K꜀ = [C]ᵏ[D]ᵈ / [A]ᵃ[B]ᵇ. K꜀ is constant only at a given temperature. Large K꜀ means products favoured. You must use equilibrium concentrations, not initial values.
平衡常数 K꜀ 以浓度表示。对于反应 aA + bB ⇌ cC + dD，K꜀ = [C]ᵏ[D]ᵈ / [A]ᵃ[B]ᵇ。K꜀ 仅在特定温度下为定值。K꜀ 值大表示产物占优势。必须使用平衡浓度，而非初始浓度。
8. Acids, Bases and pH | 酸、碱与 pH
A Brønsted–Lowry acid is a proton donor, and a base is a proton acceptor. Strong acids (HCl, HNO₃, H₂SO₄) dissociate completely; weak acids (CH₃COOH, H₂CO₃) only partially dissociate. The same applies to strong and weak bases.
布朗斯特-劳里酸是质子供体，碱是质子受体。强酸（HCl、HNO₃、H₂SO₄）完全电离；弱酸（CH₃COOH、H₂CO₃）仅部分电离。强碱与弱碱情况类似。
pH = –log₁₀[H⁺]. For strong monoprotic acids, [H⁺] equals the acid concentration. For weak acids, the acid dissociation constant Kₐ is used: Kₐ = [H⁺][A⁻]/[HA]. pKₐ = –log₁₀Kₐ. Smaller pKₐ means stronger acid.
pH = –log₁₀[H⁺]。对于一元强酸，[H⁺] 等于酸的浓度。对于弱酸，使用酸离解常数 Kₐ：Kₐ = [H⁺][A⁻]/[HA]。pKₐ = –log₁₀Kₐ。pKₐ 越小酸性越强。
Kw = [H⁺][OH⁻] = 1.0 × 10⁻¹⁴ at 298 K. In pure water, [H⁺] = [OH⁻] = 1.0 × 10⁻⁷ mol dm⁻³. Buffers resist changes in pH upon addition of small amounts of acid or alkali. An acidic buffer contains a weak acid and its conjugate base; the Henderson–Hasselbalch equation helps calculate pH: pH = pKₐ + log₁₀([A⁻]/[HA]).
水的离子积 Kw = [H⁺][OH⁻] = 1.0 × 10⁻¹⁴（298 K）。纯水中 [H⁺] = [OH⁻] = 1.0 × 10⁻⁷ mol dm⁻³。缓冲溶液能抵抗外加少量酸或碱带来的 pH 变化。酸性缓冲液含弱酸及其共轭碱；亨德森-哈塞尔巴尔赫方程可计算 pH：pH = pKₐ + log₁₀([A⁻]/[HA])。
Titration curves show pH versus volume of titrant added. Equivalence point selection for indicators depends on the strength combinations: strong acid–strong base (phenolphthalein or methyl orange), weak acid–strong base (phenolphthalein), strong acid–weak base (methyl orange).
滴定曲线展示 pH 随滴定剂体积的变化。指示剂选择取决于酸碱强度组合：强酸-强碱（酚酞或甲基橙），弱酸-强碱（酚酞），强酸-弱碱（甲基橙）。
9. Redox and Electrochemistry | 氧化还原与电化学
Oxidation is loss of electrons, reduction is gain of electrons (OIL RIG). Oxidation numbers help identify redox processes. Common rules: free elements have oxidation number 0, oxygen is usually –2 (except in peroxides), hydrogen is +1 (except in metal hydrides).
氧化丢失电子，还原则得到电子（OIL RIG）。氧化数可帮助识别氧化还原过程。常见规则：游离态元素氧化数为 0，氧通常为 –2（过氧化物除外），氢为 +1（金属氢化物除外）。
Balancing redox equations may use the half-reaction method or oxidation number changes. In acidic solution, add H₂O and H⁺ to balance oxygen and hydrogen; in basic solution, add OH⁻ and H₂O.
配平氧化还原方程式可采用半反应法或氧化数变化法。在酸性溶液中，添加 H₂O 和 H⁺ 来平衡氧和氢；在碱性溶液中，添加 OH⁻ 和 H₂O。
An electrochemical cell converts chemical energy to electrical energy. In a galvanic (voltaic) cell, a spontaneous redox reaction produces a voltage. The cell potential E꜀ₑₗₗ = E꜀ₐₜₕₒₔₑ – E꜀ₐₙₒₔₑ under standard conditions. The standard hydrogen electrode has E⦵ = 0.00 V.
电化学电池将化学能转化为电能。在原电池（伏打电池）中，自发氧化还原反应产生电压。标准条件下，电池电动势 E꜀ₑₗₗ = E꜀ₐₜₕₒₔₑ – E꜀ₐₙₒₔₑ。标准氢电极的 E⦵ = 0.00 V。
Electrolysis uses electrical energy to drive a non-spontaneous reaction. In molten salts, simple ions are discharged. In aqueous solutions, you must consider competition between water and the solute. For example, at the cathode, water is reduced in preference to reactive metals.
电解利用电能驱动非自发反应。在熔融盐中，简单离子放电。在水溶液中，需考虑水与溶质之间的竞争。例如，在阴极，水比为活泼的金属离子更易被还原。
Faraday’s laws relate quantity of charge to amount of substance produced. Q = It (charge = current × time). One mole of electrons corresponds to 96 500 C (Faraday constant). Mass of substance deposited = (Q × M) / (nF).
法拉第定律将电量与生成物质的量关联起来。Q = It（电荷量 = 电流 × 时间）。1 摩尔电子相当于 96 500 C（法拉第常数）。析出物质的质量 m = (Q × M) / (nF)。
10. Introduction to Organic Chemistry | 有机化学基础
Organic compounds contain carbon. Homologous series share the same general formula and gradation of physical properties. Functional groups determine chemical reactivity. Key series: alkanes (CₙH₂ₙ₊₂), alkenes (CₙH₂ₙ), alcohols (R–OH), carboxylic acids (R–COOH).
有机化合物均含碳。同系列具有相同的通式和递变的物理性质。官能团决定化学反应活性。重点系列：烷烃（CₙH₂ₙ₊₂）、烯烃（CₙH₂ₙ）、醇（R–OH）、羧酸（R–COOH）。
Nomenclature follows IUPAC rules: identify the longest carbon chain, number so that the principal functional group gets the lowest number, and name substituents as prefixes. Structural isomerism (chain, position, functional group) and stereoisomerism (E/Z, optical) are tested frequently.
命名遵循 IUPAC 规则：找出最长的碳链，编号使主官能团位次最低，取代基以前缀命名。结构异构（碳链异构、位置异构、官能团异构）和立体异构（E/Z 异构、光学异构）经常考查。
Alkanes undergo free-radical substitution with halogens (initiation, propagation, termination). Alkenes undergo electrophilic addition (e.g. with HBr, Br₂, H₂SO₄). Markovnikov’s rule applies to unsymmetrical alkenes. Alcohols can be oxidised to aldehydes, ketones, or carboxylic acids; distillation versus reflux controls the product.
烷烃与卤素发生自由基取代（链引发、链增长、链终止）。烯烃进行亲电加成（如与 HBr、Br₂、H₂SO₄）。马氏规则适用于不对称烯烃。醇可被氧化成醛、酮或羧酸；蒸馏与回流条件可控制产物。
Essential mechanisms: you should be able to draw curly arrows showing electron pair movement in electrophilic addition, nucleophilic substitution, and free-radical substitution. Understand primary, secondary, and tertiary carbocation stability and its impact on SN1 vs SN2 pathways.
必须掌握的机理：能画出弯箭头，表示亲电加成、亲核取代和自由基取代中的电子对转移。理解伯、仲、叔碳正离子稳定性及其对 SN1 与 SN2 路径的影响。
11. Measurement, Data Processing and Practical Skills | 测量、数据处理与实验技能
IB and OCR both assess uncertainties, errors, and graphical analysis. Know the difference between systematic errors (affect accuracy) and random errors (affect precision). Record uncertainties as ± half the smallest division or as standard deviation for repeated trials.
IB 和 OCR 都考查不确定度、误差和图像分析。需区分系统误差（影响准确度）和随机误差（影响精密度）。记录不确定度可用最小分度值的一半，或重复实验的标准偏差。
Significant figures in calculations should reflect the least precise measurement. When averaging, do not increase the number of significant figures unreasonably. Propagation of uncertainties for addition/subtraction and multiplication/division follows specific rules.
计算中的有效数字应反映最不精确的测量值。取平均值时不要不合理地增加有效数字位数。加/减法与乘/除法的误差传递各有特定规则。
Titration, calorimetry, rates of reaction with gas collection or colour change, and qualitative analysis for common ions (flame tests, precipitation reactions) are core practicals. Be ready to describe methods, identify sources of error, and suggest improvements.
酸碱滴定、量热实验、通过气体收集或颜色变化测定反应速率，以及常见离子的定性分析（焰色反应、沉淀反应）都是核心实验。准备好描述方法、识别误差来源并提出改进建议。
12. Exam Strategy and Final Tips | 考试策略与最后提示
Read the question carefully and highlight command terms such as ‘state’, ‘describe’, ‘explain’, or ‘determine’. In ‘explain’ questions, always relate back to underlying chemical principles, such as bond breaking/making, electron arrangement, or collision theory.
仔细审题，圈出指令词，如’给出’、’描述’、’解释’或’计算’。遇到’解释’类问题，务必联系根本的化学原理，如键的断裂与形成、电子排布或碰撞理论。
Show all working in calculation questions. Even if the final answer is wrong, method marks can be earned. Clearly state your final answer with correct units and to an appropriate number of significant figures.
计算题要展示所有步骤。即使最终答案错误，仍可获得过程分。清晰地写出最终答案，并带上正确单位和适当的有效数字。
During revision, practise drawing graphs with labelled axes and a line of best fit. Memorise key formulas: n = m/M, q = mcΔT, pH = –log[H⁺], and the ideal gas equation. Use flashcards for functional groups and reaction mechanisms.
复习期间，练习绘制带坐标轴标签和最佳拟合线的图表。牢记关键公式：n = m/M、q = mcΔT、pH = –log[H⁺] 以及理想气体状态方程。用抽认卡强化官能团和反应机理记忆。
Finally, maintain a positive mindset. A structured revision plan that cycles through these topics will build confidence and readiness for the end-of-term paper.
最后，保持积极心态。一份围绕上述主题循环复习的结构化计划将增加信心，让你从容应对期末考试。
Published by TutorHao | Chemistry Revision Series | aleveler.com
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