📚 AP Chemistry Must-Know Core Vocabulary for a 5 | AP化学：5分必考核心词汇汇总
Mastering the precise terminology of AP Chemistry is half the battle for a top score. This curated list brings together the essential terms you will encounter in multiple‑choice questions, free‑response prompts, and experimental design tasks. Each entry is paired with a concise Chinese translation and a brief definition to help you internalise the concepts, not just memorise words.
精准掌握 AP 化学的专业术语是拿到 5 分的关键一战。这份精编词汇表汇集了选择题、自由作答题和实验设计题中必现的核心词汇。每个词条都配有中文释义和简洁定义，帮助你在理解中内化概念，而不是死记硬背。
1. Atomic Structure & Periodicity | 原子结构与周期性
The language of electron configurations, quantum numbers, and periodic trends forms the backbone of all chemical reasoning. You must be able to interpret ionization energies, electron affinities, and shielding effects without hesitation.
电子排布、量子数和周期律的语言是化学推理的基石。你需要毫不犹豫地解读电离能、电子亲和能以及屏蔽效应。
| English Term | 中文释义 | Brief Definition |
|---|---|---|
| Atomic orbital | 原子轨道 | A region of space where there is a high probability of finding an electron. |
| Quantum numbers | 量子数 | Set of four numbers (n, l, mₗ, mₛ) that describe the state of an electron. |
| Electron configuration | 电子排布 | Distribution of electrons among orbitals of an atom. |
| Valence electrons | 价电子 | Electrons in the outermost shell that participate in bonding. |
| Effective nuclear charge (Zeff) | 有效核电荷 | Net positive charge experienced by an electron after shielding. |
| Ionization energy | 电离能 | Energy required to remove an electron from a gaseous atom. |
| Electron affinity | 电子亲和能 | Energy change when a gaseous atom gains an electron. |
| Electronegativity | 电负性 | Ability of an atom to attract shared electrons in a bond. |
| Atomic radius | 原子半径 | Half the distance between the nuclei of two identical bonded atoms. |
| Isoelectronic | 等电子的 | Atoms or ions with the same number of electrons. |
2. Chemical Bonding & Molecular Geometry | 化学键与分子几何
From Lewis structures to VSEPR theory, bonding vocabulary explains why molecules adopt particular shapes and exhibit polarity. Master hybridization, resonance, and formal charge to decode structure‑property relationships.
从路易斯结构到 VSEPR 理论，化学键词汇解释了分子为何呈现特定形状并表现出极性。掌握杂化、共振和形式电荷，才能解读结构与性质的关系。
| English Term | 中文释义 | Brief Definition |
|---|---|---|
| Covalent bond | 共价键 | Bond formed by sharing electron pairs between atoms. |
| Ionic bond | 离子键 | Electrostatic attraction between oppositely charged ions. |
| Polar covalent bond | 极性共价键 | Unequal sharing of electrons leading to partial charges. |
| Dipole moment | 偶极矩 | Measure of polarity in a molecule; separation of positive and negative charges. |
| Lewis structure | 路易斯结构式 | Diagram showing all valence electrons as dots or lines. |
| Formal charge | 形式电荷 | Charge assigned to an atom assuming equal sharing of bonding electrons. |
| Resonance | 共振 | Delocalization of electrons in molecules with multiple valid Lewis structures. |
| VSEPR theory | 价层电子对互斥理论 | Model predicting molecular geometry based on electron‑pair repulsion. |
| Hybridization | 杂化 | Mixing of atomic orbitals to form new hybrid orbitals for bonding. |
| Bond order | 键级 | Number of bonding pairs shared between two atoms. |
3. Stoichiometry & Reactions | 化学计量与反应
The quantitative heart of chemistry relies on the mole concept, limiting reactants, and reaction types. These terms let you navigate percent yield, empirical formulas, and redox processes with confidence.
化学的定量核心依赖于摩尔概念、限域反应物和反应类型。这些术语让你自信地处理产率百分比、经验式和氧化还原过程。
| English Term | 中文释义 | Brief Definition |
|---|---|---|
| Mole | 摩尔 | Amount of substance containing Avogadro's number (6.022 × 10²³) of entities. |
| Molar mass | 摩尔质量 | Mass of one mole of a substance (g/mol). |
| Empirical formula | 经验式（最简式） | Simplest whole‑number ratio of atoms in a compound. |
| Molecular formula | 分子式 | Actual number of atoms of each element in a molecule. |
| Limiting reactant | 限域反应物 | Reactant completely consumed first, determining the amount of product. |
| Excess reactant | 过量反应物 | Reactant left over after the limiting reactant is used up. |
| Percent yield | 产率百分比 | (Actual yield / theoretical yield) × 100%. |
| Redox reaction | 氧化还原反应 | Reaction involving transfer of electrons; one species is oxidized, another reduced. |
| Oxidation number | 氧化数 | Hypothetical charge assigned to an atom in a compound. |
| Precipitation reaction | 沉淀反应 | Formation of an insoluble solid (precipitate) from mixing two solutions. |
4. Gases & Gas Laws | 气体与气体定律
Kinetic molecular theory and the ideal gas law connect macroscopic measurable properties to microscopic particle behavior. Terms like partial pressure and root‑mean‑square speed appear frequently in both calculation and explanation questions.
动力学分子理论和理想气体定律将宏观可测性质与微观粒子行为联系起来。分压和均方根速率等术语在计算和解释题中频繁出现。
| English Term | 中文释义 | Brief Definition |
|---|---|---|
| Ideal gas | 理想气体 | tical gas obeying PV = nRT exactly; particles have no volume and no intermolecular forces. |
| Boyle's law | 波义耳定律 | At constant T, PV = constant (P₁V₁ = P₂V₂). |
| Charles's law | 查理定律 | At constant P, V ∝ T (V₁/T₁ = V₂/T₂). |
| Avogadro's law | 阿伏伽德罗定律 | At constant P and T, V ∝ n. |
| Partial pressure | 分压 | Pressure exerted by an individual gas in a mixture (Dalton's law). |
| Kinetic molecular theory | 动力学分子理论 | Model explaining gas behavior based on particles in constant random motion. |
| Root‑mean‑square speed (urms) | 均方根速率 | Measure of the average speed of gas particles; urms ∝ √T/M. |
| STP | 标准状况 | Standard temperature and pressure: 0 °C (273 K) and 1 atm. |
| Molar volume | 摩尔体积 | Volume occupied by one mole of a gas at STP ≈ 22.4 L. |
5. Thermochemistry | 热化学
Energy changes in chemical processes are expressed through enthalpy, calorimetry, and Hess's law. These terms are the foundation for analyzing bond energies, heat capacity, and the direction of heat flow.
化学过程中的能量变化通过焓、量热法和盖斯定律来表达。这些术语是分析键能、热容和热流方向的基础。
| English Term | 中文释义 | Brief Definition |
|---|---|---|
| Enthalpy (ΔH) | 焓变 | Total heat content of a system at constant pressure. |
| Exothermic | 放热 | Process releasing heat; ΔH < 0. |
| Endothermic | 吸热 | Process absorbing heat; ΔH > 0. |
| Specific heat capacity | 比热容 | Energy needed to raise 1 g of a substance by 1 °C (or 1 K). |
| Calorimeter | 量热计 | Device used to measure heat changes in a chemical or physical process. |
| Hess's law | 盖斯定律 | Overall enthalpy change for a reaction is the sum of the enthalpy changes for the individual steps. |
| Standard enthalpy of formation (ΔHf°) | 标准生成焓 | Enthalpy change when one mole of a compound is formed from its elements in their standard states. |
| Bond dissociation energy | 键解离能 | Energy required to break one mole of a specific bond in the gas phase. |
| Heat of reaction | 反应热 | Enthalpy change for a reaction as written. |
6. Kinetics | 动力学
The speed of reactions is governed by collision theory, rate laws, and activation energy. These terms clarify why concentration, temperature, and catalysts alter reaction rates and how to determine rate orders from experimental data.
反应速率由碰撞理论、速率定律和活化能支配。这些术语阐明了为何浓度、温度和催化剂会改变反应速率，以及如何从实验数据确定反应级数。
| English Term | 中文释义 | Brief Definition |
|---|---|---|
| Rate law | 速率定律 | Equation relating reaction rate to reactant concentrations: rate = k[A]ᵐ[B]ⁿ. |
| Rate constant (k) | 速率常数 | Proportionality constant in the rate law; temperature‑dependent. |
| Order of reaction | 反应级数 | Sum of exponents in the rate law (e.g., zero‑order, first‑order). |
| Activation energy (Ea) | 活化能 | Minimum energy required for reactant molecules to undergo a reaction. |
| Catalyst | 催化剂 | Substance that increases reaction rate without being consumed; lowers Ea. |
| Reaction intermediate | 反应中间体 | Species produced in one step and consumed in a later step; not appearing in the overall equation. |
| Rate‑determining step | 速率决定步骤 | Slowest elementary step in a reaction mechanism that governs the overall rate. |
| Collision theory | 碰撞理论 | Reactions occur when particles collide with proper orientation and sufficient energy. |
| Half‑life (t½) | 半衰期 | Time required for the concentration of a reactant to decrease by half. |
7. Equilibrium | 化学平衡
Dynamic equilibrium and Le Châtelier's principle are central to predicting reaction behavior under stress. Knowing the meaning of Kc, Kp, and Q is essential for solving equilibrium problems that appear on every AP exam.
动态平衡和勒夏特列原理是预测反应在压力下行为的核心。理解 Kc、Kp 和 Q 的含义对于解决每次 AP 考试必出的平衡问题至关重要。
| English Term | 中文释义 | Brief Definition |
|---|---|---|
| Chemical equilibrium | 化学平衡 | State where forward and reverse reaction rates are equal; concentrations remain constant. |
| Equilibrium constant (Kc, Kp) | 平衡常数 | Ratio of product concentrations to reactant concentrations, each raised to their coefficients, at equilibrium. |
| Reaction quotient (Q) | 反应商 | Values calculated using current (non‑equilibrium) concentrations to predict shift direction. |
| Le Châtelier's principle | 勒夏特列原理 | A system at equilibrium will shift to relieve a stress (change in concentration, T, or P). |
| Dynamic equilibrium | 动态平衡 | Continuous forward and reverse processes occurring at equal rates. |
| Heterogeneous equilibrium | 多相平衡 | Equilibrium involving species in more than one phase; pure solids and liquids omitted from K expression. |
| ICE table | ICE 表（初始‑变化‑平衡） | Tool for organizing Initial, Change, and Equilibrium concentrations to solve equilibrium problems. |
8. Acids & Bases | 酸碱
Brønsted‑Lowry definitions, pH calculations, and strength comparisons dominate this topic. Fluency with Ka, Kb, and the behavior of conjugate pairs is mandatory for acid‑base titration free‑response questions.
布朗斯特‑劳里定义、pH 计算和强度比较主导了这一主题。熟练掌握 Ka、Kb 及共轭酸碱对的行为是酸碱滴定向答题的必修课。
| English Term | 中文释义 | Brief Definition |
|---|---|---|
| Brønsted‑Lowry acid | 质子酸 | Proton (H⁺) donor. |
| Brønsted‑Lowry base | 质子碱 | Proton (H⁺) acceptor. |
| Conjugate acid‑base pair | 共轭酸碱对 | Two species differing by one H⁺. |
| Acid dissociation constant (Ka) | 酸解离常数 | Equilibrium constant for the dissociation of an acid; larger Ka = stronger acid. |
| Base dissociation constant (Kb) | 碱解离常数 | Equilibrium constant for the dissociation of a base. |
| pH | pH | Negative logarithm of hydrogen ion concentration: pH = –log[H⁺]. |
