Chemistry Prep (Chem 11 Bridge) 化学预备课程（衔接 AP Chem）
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· 7 units · key topics drilled across the official outline
· Next exam: 2026-05-04 · 2026-05-04
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Course outline
Unit 1 · Measurement and Math Foundations 测量与数学基础
Exam weight: Foundational
1.1 — SI Units and Unit Conversion 国际单位制与单位换算
· Seven SI base units (m, kg, s, mol, K, A, cd) and the most common derived units · SI prefixes from pico- (10^-12) to giga- (10^9) · Converting between units by multiplying by 1 (the conversion-factor identity)
1.2 — Scientific Notation and Orders of Magnitude 科学计数法与数量级
· Writing very large or very small numbers as a × 10^n where 1 ≤ |a| < 10 · Multiplying, dividing, adding scientific-notation values · Estimating answers by comparing exponents (order-of-magnitude reasoning)
1.3 — Significant Figures 有效数字
· Counting sig figs: nonzero digits, zeros between digits, trailing zeros after a decimal · Multiplication/division: result has fewest sig figs of any input · Addition/subtraction: result has fewest decimal places of any input · Exact numbers (counted quantities, defined factors) have infinite sig figs
1.4 — Precision, Accuracy, and Measurement Uncertainty 精密度、准确度与测量误差
· Accuracy = closeness to the true value; precision = repeatability of measurements · Random vs systematic error · Percent error: |measured − true| / true × 100% · Reporting measurements with the instrument's uncertainty (± value)
1.5 — Dimensional Analysis (Factor-Label Method) 量纲分析（因子标签法）
· Treat units as algebraic quantities that cancel like variables · Chain conversion factors until target units remain · Use this method for every chemistry calculation — it catches errors · Multi-step conversions: grams → moles → particles, etc.
1.6 — Reading and Constructing Graphs 读图与作图
· Independent variable on the x-axis, dependent on the y-axis · Labeled axes with units; appropriate scale · Linear vs nonlinear relationships; identifying proportionality · Best-fit lines and reading slope/intercept
Unit 2 · Matter and Its Classification 物质与分类
Exam weight: Foundational
2.1 — States of Matter and Phase Changes 物质的三态与相变
· Solid, liquid, gas — particle-level pictures · Phase change names: melting, freezing, vaporization (boiling/evaporation), condensation, sublimation, deposition · Phase changes are physical changes; particles stay the same · Plasma briefly — fourth state, ionized gas
2.2 — Physical vs Chemical Properties and Changes 物理与化学性质、变化
· Physical property: observed without changing the identity (mass, density, mp, bp) · Chemical property: describes how a substance reacts (flammability, reactivity) · Signs of chemical change: gas evolution, color change, temperature change, precipitate, light · Conservation of mass in both physical and chemical changes
2.3 — Pure Substances, Elements, and Compounds 纯净物、元素与化合物
· Pure substance: uniform composition throughout · Element: one type of atom; symbol from periodic table · Compound: two or more elements chemically bonded in a fixed ratio · Law of definite proportions
2.4 — Mixtures: Homogeneous vs Heterogeneous 混合物：均一与非均一
· Homogeneous: uniform composition (solutions, alloys) · Heterogeneous: visibly different regions (suspension, sand-in-water) · Solution language: solute dissolves in solvent · Mixtures have variable composition; components keep their properties
2.5 — Separation Techniques 分离技术
· Filtration: separates insoluble solid from liquid · Distillation: separates by different boiling points · Evaporation/crystallization: removes solvent, leaves solute · Chromatography: separates by differential affinity (introductory) · Decantation, centrifugation (briefly)
Unit 3 · Atomic Structure and the Periodic Table 原子结构与元素周期表
Exam weight: Foundational
3.1 — Subatomic Particles and Atomic Notation 亚原子粒子与原子符号
· Proton (+1, in nucleus), neutron (0, in nucleus), electron (-1, in shells) · Atomic number Z = number of protons (defines the element) · Mass number A = protons + neutrons · Notation: ᴬ_Z X, e.g. ¹²₆C
3.2 — Isotopes and Average Atomic Mass 同位素与相对原子质量
· Isotopes: same Z, different A (different neutron count) · Average atomic mass = Σ (isotope mass × fractional abundance) · Chemical behavior of isotopes is essentially identical · Radioactive isotopes (intro idea)
3.3 — Periodic Table Layout and Families 周期表的结构与族
· Periods = horizontal rows (1–7); groups = vertical columns (1–18 / IA–VIIIA + B) · Main families: alkali metals (1), alkaline earth (2), halogens (17), noble gases (18) · Transition metals (3–12), lanthanides + actinides · Same-group elements share similar chemical behavior
3.4 — Metals, Nonmetals, and Metalloids 金属、非金属与类金属
· Metals: left of staircase, malleable, conductive, form cations · Nonmetals: right of staircase, brittle, poor conductors, form anions or covalent bonds · Metalloids: along the staircase line (B, Si, Ge, As, Sb, Te), in-between properties
3.5 — Bohr Model and Electron Shells 玻尔模型与电子壳层
· Electrons orbit in shells (energy levels) labelled n = 1, 2, 3, ... · Shell capacities (early model): 2, 8, 8, 18, ... electrons · Valence electrons = outermost-shell electrons; determine chemical behavior · Bohr model is an approximation; AP Chem replaces it with orbitals later
3.6 — Periodic Trends (Qualitative) 周期性递变（定性）
· Atomic radius: decreases across a period, increases down a group · First ionization energy: increases across, decreases down · Metallic character: decreases across, increases down · Reasoning: more protons + same shell → tighter pull (across); larger shells → looser hold (down)
3.7 — Ion Formation and the Octet Rule 离子形成与八电子规则
· Atoms gain/lose electrons to achieve a noble-gas configuration (octet) · Group 1 → +1, Group 2 → +2, Group 13 → +3 cations · Group 15 → -3, Group 16 → -2, Group 17 → -1 anions · Transition metals often have multiple possible charges (handled in U4.5) · Cation/anion size compared to neutral atom
Unit 4 · Chemical Bonds and Nomenclature 化学键与化合物命名
Exam weight: Foundational
4.1 — Ionic vs Covalent Bonds (The Distinction) 离子键 vs 共价键（区别）
· Ionic: electrons transferred; metal + nonmetal; forms crystals; high mp/bp · Covalent: electrons shared; nonmetal + nonmetal; molecules or networks · Electronegativity difference: large → ionic, small → covalent · Conductivity test: ionic solutions conduct, most covalent compounds don't
4.2 — Monatomic Ion Charges from Group Numbers 由族数推断单原子离子电荷
· Main-group ions: Group 1→+1, 2→+2, 13→+3, 15→−3, 16→−2, 17→−1 · Achieving isoelectronic configuration with nearest noble gas · Group 14 (C, Si) usually forms covalent bonds, not ions · Naming monatomic anions: stem + -ide (chloride, oxide, nitride, ...)
4.3 — Polyatomic Ions 多原子离子
· Key list to memorize: NO3⁻, SO4²⁻, CO3²⁻, PO4³⁻, OH⁻, NH4⁺, ClO3⁻, MnO4⁻, CrO4²⁻, etc. · -ate vs -ite (oxyanions): -ate is the 'common' (more O), -ite has one less O · Per- prefix adds one O above -ate; hypo- removes one below -ite · Polyatomic ions stay together as a unit in formulas and reactions
4.4 — Naming Binary Ionic Compounds 二元离子化合物命名
· Cation name + anion name (-ide for binary) · Use criss-cross rule to balance charges: e.g. Al³⁺ + O²⁻ → Al2O3 · Always reduce subscripts to lowest whole-number ratio (formula unit) · Examples: NaCl, MgBr2, K2O, Al2O3, Ca3N2
4.5 — Transition Metal Compounds and Roman Numerals 过渡金属化合物与罗马数字命名
· Transition metals often have multiple oxidation states (Fe²⁺ vs Fe³⁺) · Stock notation: cation followed by charge in Roman numerals — iron(II), iron(III) · Determine the charge by balancing with the anion charges · Special non-transition variable charges: Sn²⁺/Sn⁴⁺, Pb²⁺/Pb⁴⁺
4.6 — Naming Binary Covalent Compounds (Prefix System) 二元共价化合物命名（前缀法）
· Prefixes: mono-, di-, tri-, tetra-, penta-, hexa-, hepta-, octa-, nona-, deca- · Drop 'mono-' on the first element (CO is 'carbon monoxide', not 'monocarbon monoxide') · Examples: CO2 = carbon dioxide, N2O4 = dinitrogen tetroxide, P4O10 = tetraphosphorus decoxide · Used only when both elements are nonmetals
4.7 — Naming Acids 酸的命名
· Binary acids (H + nonmetal in solution): hydro- + stem + -ic acid (HCl → hydrochloric acid) · Oxyacids from -ate ions: stem + -ic acid (NO3⁻ → nitric acid, HNO3) · Oxyacids from -ite ions: stem + -ous acid (NO2⁻ → nitrous acid, HNO2) · Match acid name to the parent anion's name pattern
4.8 — Hydrates (Crystal Water) 水合物（结晶水）
· Hydrate: ionic compound with water molecules built into the crystal · Notation: CuSO4·5H2O (read 'copper(II) sulfate pentahydrate') · Heating drives off water → anhydrous form · Mass of water can be used to compute the hydrate formula
Unit 5 · Chemical Reactions 化学反应
Exam weight: Foundational
5.1 — Anatomy of a Chemical Equation 化学方程式的结构
· Reactants → products; arrow direction; reversibility (⇌) · Coefficients (in front) vs subscripts (within formula) · State symbols: (s), (l), (g), (aq) — solid, liquid, gas, aqueous · Word equation → skeleton equation → balanced equation
5.2 — Balancing Equations by Inspection 用观察法配平化学方程
· Conservation of mass: same atoms on both sides · Adjust coefficients only; never change subscripts · Strategy: balance elements that appear once first; balance polyatomic ions as units; balance H and O last · Multiply through to clear fractional coefficients
5.3 — Five Reaction Types 五种反应类型
· Synthesis (combination): A + B → AB · Decomposition: AB → A + B · Single replacement: A + BC → AC + B · Double replacement (metathesis): AB + CD → AD + CB · Combustion: hydrocarbon + O2 → CO2 + H2O
5.4 — Activity Series of Metals 金属活动性顺序
· Order from most reactive to least: K, Na, Ca, Mg, Al, Zn, Fe, Pb, (H), Cu, Ag, Au · A metal will replace any metal below it from a compound · Metals above H react with acids to release H2; metals below H don't · Halogen activity (F > Cl > Br > I) governs halogen single-replacement
5.5 — Solubility Rules 溶解性规则
· Always soluble: Group 1 cations, NH4⁺, NO3⁻, acetates, most ClO3⁻/ClO4⁻ · Halides soluble EXCEPT Ag⁺, Pb²⁺, Hg2²⁺ salts · Sulfates soluble EXCEPT Ba²⁺, Pb²⁺, Ca²⁺ (slightly), Sr²⁺ · Carbonates, phosphates, sulfides, hydroxides mostly INSOLUBLE (with Group 1 / NH4⁺ exceptions)
5.6 — Predicting Products of Common Reactions 常见反应的产物预测
· Combination of metal + nonmetal → ionic compound (charges from group numbers) · Decomposition of metal carbonates → metal oxide + CO2 · Single replacement with activity series · Double replacement — use solubility rules to identify the precipitate
5.7 — Net Ionic Equations (Introduction) 净离子方程式（入门）
· Strong electrolytes dissociate fully in water (write ions) · Insoluble solids, gases, weak electrolytes stay as molecules/formula units · Spectator ions appear unchanged on both sides — cancel them · Net ionic equation shows only the species that change
Unit 6 · The Mole and Stoichiometry 摩尔与化学计量
Exam weight: Foundational (the core of Chem 11)
6.1 — The Mole Concept and Avogadro's Number 摩尔概念与阿伏伽德罗常数
· 1 mole = 6.022 × 10²³ particles (atoms, molecules, or formula units) · Mole is to chemistry what 'dozen' is to eggs — a counting unit for very small things · Symbol n; SI base unit · Conversion: particles ↔ moles using NA
6.2 — Molar Mass Calculations 摩尔质量计算
· Molar mass (g/mol) is numerically equal to the atomic / formula mass · Sum the atomic masses for every atom in the formula · Multiply through parentheses by their subscripts: (NH4)2SO4 → 2N + 8H + S + 4O · Include water of hydration when given: CuSO4·5H2O includes 5 × H2O
6.3 — Mole ↔ Mass ↔ Particles Conversions 摩尔 ↔ 质量 ↔ 粒子数 换算
· n = (moles from mass) · m = n × M (mass from moles) · N = n × NA (particles from moles) · Use dimensional analysis to chain: g → mol → particles (or atoms-of-element-within-compound)
6.4 — Percent Composition by Mass 质量百分组成
· % X = (mass of X in 1 mol of compound / molar mass of compound) × 100% · Sum of percent compositions = 100% · Useful for purity checks and converting between mass and composition
6.5 — Empirical and Molecular Formulas 实验式与分子式
· Empirical: simplest whole-number ratio (CH2O for glucose) · Molecular: actual ratio (C6H12O6 for glucose) · Procedure: g of each element → moles → divide by smallest → multiply if needed · Use molar mass to scale empirical into molecular formula
6.6 — Mole Ratios from Balanced Equations 由配平方程读取摩尔比
· Coefficients give the mole ratio between any two species · Example 2H2 + O2 → 2H2O — 2 mol H2 : 1 mol O2 : 2 mol H2O · Mole ratios are the conversion factors for stoichiometry · Same equation gives many ratios; pick the pair you need
6.7 — Mass-to-Mass Stoichiometry 质量-质量化学计量
· Three-step path: mass A → mol A → mol B → mass B · Step 1 use molar mass of A; step 2 use mole ratio from balanced equation; step 3 use molar mass of B · Always write down the balanced equation FIRST · Check: units cancel cleanly
6.8 — Limiting and Excess Reactants 限量反应物与过量反应物
· Limiting reactant = the one that runs out first; controls how much product forms · Calculate moles of each reactant available; divide by its coefficient; smallest quotient = limiting · Excess reactant: the leftover one · Compute remaining mass of excess by subtracting consumed amount
6.9 — Percent Yield 产率
· Theoretical yield = max product from stoichiometry (assumes 100%) · Actual yield = what's measured in lab · % yield = (actual / theoretical) × 100% · Why yield is less than 100% in practice
6.10 — Combustion Analysis (Intro) 燃烧分析（入门）
· Burn an organic compound in excess O2; collect and weigh CO2 and H2O · All C in CO2 came from sample; all H in H2O came from sample · Mass of O in sample = (sample mass) − (C mass + H mass) · From masses → moles → empirical formula
Unit 7 · Solutions, Gas Laws, and Energy Basics 溶液、气体定律与能量基础
Exam weight: Foundational
7.1 — Solubility, Saturation, and Solubility Curves 溶解性、饱和度与溶解度曲线
· Unsaturated, saturated, supersaturated solutions · Solubility = mass of solute per 100 g water at a given temperature · Reading solubility curves; effect of temperature for solids vs gases · 'Like dissolves like' — polar dissolves polar, nonpolar dissolves nonpolar
7.2 — Molarity 物质的量浓度（摩尔浓度）
· M = mol solute / L solution (NOT L of solvent) · Calculate moles, then volume, then divide · Solution prep: weigh solute, dissolve, then dilute to volume mark · Other concentration units exist (molality, mass %) but molarity is the AP default
7.3 — Dilution 稀释
· M₁V₁ = M₂V₂ (moles of solute conserved when adding solvent) · Both sides must use the same volume unit · Stock solution → working solution · Cannot use this for reactions, only for changing concentration
7.4 — Solution Stoichiometry and Titration (Intro) 溶液化学计量与滴定（入门）
· Combine M = with mole ratio from balanced equation · Acid-base titration: at equivalence, moles acid·H = moles base·OH · Endpoint indicated by indicator color change · Calculation skeleton: moles of standard → moles of unknown → concentration of unknown
7.5 — Boyle's, Charles's, and Combined Gas Laws 玻意耳、查理与组合气体定律
· Boyle: PV = constant at constant T, n (P₁V₁ = P₂V₂) · Charles: = constant at constant P, n (V₁/T₁ = V₂/T₂); T must be in Kelvin · Gay-Lussac: = constant at constant V, n · Combined: P₁V₁/T₁ = P₂V₂/T₂
7.6 — The Ideal Gas Law 理想气体方程
· PV = nRT; R = 0.0821 L·atm/(mol·K) or 8.314 J/(mol·K) · Always use Kelvin for T · Pressure units must match R (atm with 0.0821; Pa with 8.314) · Solve any of P, V, n, T given the other three
7.7 — Gas Stoichiometry at STP STP 下的气体化学计量
· Standard temperature and pressure: 0 °C (273 K), 1 atm · Molar volume of any ideal gas at STP = 22.4 L/mol · Volume of gas ↔ moles using 22.4 L/mol at STP · Outside STP, use PV = nRT instead
7.8 — Endothermic vs Exothermic Reactions 吸热反应 vs 放热反应
· Exothermic: releases heat to surroundings (ΔH < 0) · Endothermic: absorbs heat from surroundings (ΔH > 0) · Energy diagrams: reactants → activation energy peak → products; products lower for exo, higher for endo · Heat of reaction can be written in the equation as a separate term
7.9 — Specific Heat Capacity and Calorimetry 比热容与量热法
· q = m × c × ΔT (heat = mass × specific heat × temp change) · Units: J = g × (·°C) × °C · Specific heat of water = 4.18 J/(g·°C) · Coffee-cup calorimetry: heat lost by hot object = heat gained by cold object
7.10 — Acid-Base Basics and the pH Scale 酸碱基础与 pH 标度
· Arrhenius: acid releases H⁺ in water, base releases OH⁻ · pH = -log[H⁺]; pOH = -log[OH⁻]; pH + pOH = 14 (at 25 °C) · Strong acids (HCl, HBr, HI, HNO3, H2SO4, HClO4) fully dissociate; strong bases (group 1 hydroxides, Ca/Sr/Ba hydroxides) · Weak acids/bases ionize partially — preview of AP U8