📚 Formula & Theorem Quick Reference Handbook | 公式定理速查手册
This handbook compiles the most essential formulas, definitions and key principles needed for the Year 10 Edexcel Chemistry course. Use it as a rapid revision tool to strengthen your understanding of quantitative chemistry, atomic structure and reaction patterns.
本手册汇编了 Year 10 Edexcel 化学课程中最核心的公式、定义与定理。可用作快速复习工具,帮助你夯实计量化学、原子结构与反应规律的基础。
1. Atomic Structure & Isotopes | 原子结构与同位素
An atom consists of a nucleus containing protons and neutrons, surrounded by electrons arranged in shells.
原子由包含质子和中子的原子核以及分层排布的核外电子构成。
Atomic number (Z) = number of protons. Mass number (A) = number of protons + number of neutrons.
原子序数 (Z) = 质子数。质量数 (A) = 质子数 + 中子数。
Number of neutrons = A – Z
neutrons = A − Z
Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons.
同位素是质子数相同而中子数不同的同种元素的原子。
Electrons fill shells in the order 2, 8, 8 for the first 20 elements; the outer shell is called the valence shell.
前 20 号元素电子按照 2, 8, 8 的顺序填充;最外层称为价电子层。
2. Relative Atomic Mass & Relative Molecular Mass | 相对原子质量与相对分子质量
Relative atomic mass (Aᵣ) is the average mass of an atom of an element compared to 1/12 the mass of a carbon‑12 atom.
相对原子质量 (Aᵣ) 是一个元素原子的平均质量与一个碳‑12 原子质量的 1/12 的比值。
Relative molecular mass (Mᵣ) is the sum of the relative atomic masses of the atoms in a molecule. For ionic compounds we use relative formula mass (also called Mᵣ).
相对分子质量 (Mᵣ) 是分子中各原子的相对原子质量之和。对于离子化合物,我们使用相对式量 (同样记作 Mᵣ)。
To calculate Aᵣ from isotopic abundances, use:
Aᵣ = Σ (isotopic mass × % abundance) / 100
利用同位素丰度计算 Aᵣ 时使用:
Aᵣ = Σ(同位素质量 × 丰度百分比) / 100
| Isotope | Mass number | % abundance |
|---|---|---|
| ³⁵Cl | 35 | 75 |
| ³⁷Cl | 37 | 25 |
Aᵣ(Cl) = (35 × 75 + 37 × 25) / 100 = 35.5
氯的相对原子质量 Aᵣ(Cl) = (35×75 + 37×25)/100 = 35.5
3. The Mole & Avogadro’s Constant | 摩尔与阿伏伽德罗常数
The mole is the SI unit for amount of substance. One mole contains exactly 6.02 × 10²³ particles (Avogadro’s constant, Nₐ).
摩尔是物质的量的 SI 单位。1 摩尔物质精确包含 6.02 × 10²³ 个微粒 (阿伏伽德罗常数 Nₐ)。
amount (mol) = mass (g) / molar mass (g mol⁻¹) ⟹ n = m / Mᵣ
物质的量 (mol) = 质量 (g) / 摩尔质量 (g mol⁻¹) ,即 n = m / Mᵣ
n = N / Nₐ
其中 N 为粒子个数。
Molar mass (M) has the same numerical value as relative formula mass (Mᵣ) but is expressed in g mol⁻¹.
摩尔质量 (M) 的数值与相对式量 (Mᵣ) 相同,但以 g mol⁻¹ 为单位。
4. Reacting Mass Calculations | 反应质量计算
Stoichiometry uses the balanced chemical equation to find the masses of reactants and products.
化学计量法利用配平的化学方程式求算反应物与生成物的质量。
Steps: (1) Write the balanced equation. (2) Convert given mass to moles using n = m / Mᵣ. (3) Use the mole ratio from the equation. (4) Convert moles of the target substance back to mass.
步骤: (1) 写出配平方程式; (2) 用 n = m / Mᵣ 将已知质量换算为物质的量; (3) 利用方程式中的物质的量比; (4) 将目标物质的物质的量换算回质量。
Example: What mass of H₂O is produced when 4.0 g of H₂ burns? 2H₂ + O₂ → 2H₂O
示例: 4.0 g H₂ 燃烧生成多少克 H₂O? 2H₂ + O₂ → 2H₂O
n(H₂) = 4.0 / 2 = 2.0 mol; mole ratio H₂ : H₂O = 2 : 2, so n(H₂O) = 2.0 mol; m(H₂O) = 2.0 × 18 = 36 g
n(H₂) = 4.0/2 = 2.0 mol; 物质的量比 H₂ : H₂O = 2:2,故 n(H₂O) = 2.0 mol; m(H₂O) = 2.0 × 18 = 36 g
5. Concentration of Solutions | 溶液的浓度
Concentration describes how much solute is dissolved in a given volume of solvent.
浓度描述一定体积溶剂中溶解了多少溶质。
c = n / V
c = 物质的量浓度 (mol dm⁻³), n = 物质的量 (mol), V = 溶液体积 (dm³)
Mass concentration can also be used:
mass concentration (g dm⁻³) = mass of solute (g) / volume (dm³)
To convert: c (mol dm⁻³) = mass concentration (g dm⁻³) / Mᵣ
换算: 物质的量浓度 (mol dm⁻³) = 质量浓度 (g dm⁻³) / Mᵣ
Remember: 1 dm³ = 1000 cm³. Titration calculations often use n = cV (with V in dm³).
注意: 1 dm³ = 1000 cm³。滴定计算常用 n = cV (V 以 dm³ 为单位)。
6. Gas Volumes (Molar Volume) | 气体体积 (摩尔体积)
At room temperature and pressure (RTP, 20 °C and 1 atm), one mole of any gas occupies 24 dm³ (or 24 000 cm³).
在常温常压下 (RTP, 20 °C、1 atm), 1 摩尔任何气体的体积均为 24 dm³ (即 24 000 cm³)。
V (dm³) = n × 24
气体体积 V (dm³) = 物质的量 n (mol) × 24 dm³ mol⁻¹
This only applies to gases and allows conversion between moles and volume without measuring density.
该关系仅适用于气体,可绕过密度直接实现物质的量与体积的换算。
Example: Calculate the volume of 0.50 mol CO₂ at RTP: V = 0.50 × 24 = 12 dm³
示例: 0.50 mol CO₂ 在 RTP 下的体积 V = 0.50 × 24 = 12 dm³
7. Percentage Yield & Atom Economy | 产率与原子经济性
Percentage yield measures how much product was actually obtained compared to the theoretical maximum.
产率衡量实际获得的产品量与理论最大产量的比值。
% yield = (actual yield / theoretical yield) × 100%
实际产率取决于副反应、分离损耗等因素。
Atom economy evaluates how efficiently atoms from reactants end up in the desired product.
原子经济性评估反应物中的原子有多少进入了目标产物。
% atom economy = (Mᵣ of desired product / total Mᵣ of all reactants) × 100%
高原子经济性意味着“绿色化学”,废物少、原料利用率高。
Example: Fe₂O₃ + 3CO → 2Fe + 3CO₂; Mᵣ(Fe) = 56, Mᵣ(Fe₂O₃) = 160, Mᵣ(CO) = 28. Atom economy for Fe = (2×56) / (160 + 3×28) × 100% ≈ 46.7%
示例: 用该反应冶炼铁,目标产物 Fe 的原子经济性 = (2×56) / (160 + 3×28) × 100% ≈ 46.7%
8. Empirical & Molecular Formulae | 经验式与分子式
The empirical formula gives the simplest whole‑number ratio of atoms of each element in a compound.
经验式表示化合物中各元素原子的最简整数比。
To find it from mass or percentage data: (1) divide the mass (or %) of each element by its Aᵣ; (2) divide each result by the smallest number; (3) write the ratio as whole numbers.
由质量或百分含量求经验式的步骤: (1) 各元素的质量 (或 %) 除以其 Aᵣ; (2) 用最小结果值除所有结果; (3) 化为整数比。
Example: a compound contains 40.0% C, 6.7% H, 53.3% O. mol ratio C : H : O = (40/12) : (6.7/1) : (53.3/16) = 3.33 : 6.7 : 3.33 ≈ 1 : 2 : 1. Empirical formula = CH₂O.
示例: 含 40.0% C, 6.7% H, 53.3% O, 摩尔比 C:H:O ≈ 1:2:1, 经验式 CH₂O。
Molecular formula = (empirical formula)ₙ, where n = Mᵣ of compound / Mᵣ of empirical formula.
分子式 = (经验式)ₙ, 其中 n = 化合物的 Mᵣ / 经验式的 Mᵣ。
9. Ionic Equations | 离子方程式
An ionic equation shows only the species that actually change during the reaction; spectator ions are omitted.
离子方程式仅显示反应中实际发生变化的微粒,省略旁观离子。
Steps: (1) Write the balanced full equation with state symbols. (2) Split aqueous ionic compounds into their ions. (3) Cancel identical ions on both sides. (4) Write the net ionic equation, ensuring charges and atoms balance.
步骤: (1) 写出带状态符号的配平方程式; (2) 将可溶性强电解质拆成离子; (3) 删除两边相同的离子; (4) 得到净离子方程式并确保电荷与原子守恒。
Example: AgNO₃(aq) + NaCl(aq) → AgCl(s) + NaNO₃(aq). Net ionic: Ag⁺(aq) + Cl⁻(aq) → AgCl(s).
示例: AgNO₃(aq) + NaCl(aq) → AgCl(s) + NaNO₃(aq), 净离子方程式: Ag⁺(aq) + Cl⁻(aq) → AgCl(s)。
State symbols: (s) solid, (l) liquid, (g) gas, (aq) aqueous (dissolved in water).
状态符号: (s) 固体, (l) 液体, (g) 气体, (aq) 水溶液。
10. Key Laws & Reaction Patterns | 重要定律与反应规律
Law of Conservation of Mass: mass is neither created nor destroyed in a chemical reaction; total mass of reactants equals total mass of products.
质量守恒定律: 化学反应中质量不会凭空产生或消失,反应物总质量等于生成物总质量。
Law of Constant Composition: a pure compound always contains the same elements in the same proportion by mass.
定组成定律: 纯净物中各元素的质量组成总是固定的。
Neutralisation: acid + base → salt + water. In terms of ions, H⁺(aq) + OH⁻(aq) → H₂O(l).
中和反应: 酸 + 碱 → 盐 + 水。从离子角度看, H⁺(aq) + OH⁻(aq) → H₂O(l)。
Metal + acid → salt + hydrogen gas. Example: Mg(s) + 2HCl(aq) → MgCl₂(aq) + H₂(g).
金属 + 酸 → 盐 + 氢气。例如: Mg(s) + 2HCl(aq) → MgCl₂(aq) + H₂(g)。
Metal oxide/hydroxide + acid → salt + water. CuO(s) + H₂SO₄(aq) → CuSO₄(aq) + H₂O(l).
金属氧化物/氢氧化物 + 酸 → 盐 + 水。CuO(s) + H₂SO₄(aq) → CuSO₄(aq) + H₂O(l)。
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