AS AQA Organic Chemistry Topic Test Guide | AS AQA 有机化学专题测试指南

📚 AS AQA Organic Chemistry Topic Test Guide | AS AQA 有机化学专题测试指南

Organic chemistry is a major part of the AS AQA (OxfordAQA International) Chemistry specification. This revision guide condenses the key ideas, mechanisms and test-tube reactions you need, and shows common errors to avoid in a topic test.

有机化学是 AS AQA（牛津AQA国际考试）化学大纲中占权重很大的内容。本复习指南浓缩了考试所需的核心理念、反应机理和试管检验方法，并指出了专题测试中常见的失分点。

---

1. Nomenclature and Isomerism | 命名法与同分异构

According to IUPAC rules, the longest continuous carbon chain containing the functional group gives the stem: C1 meth, C2 eth, C3 prop, C4 but. The functional group suffix determines the family, and numbers locate substituents and the functional group, with the lowest possible locants.

根据IUPAC命名规则，包含官能团的最长连续碳链决定主链词干：C1 meth、C2 eth、C3 prop、C4 but。官能团后缀决定化合物类别，用数字标明取代基和官能团位置，且位次数字尽可能小。

Structural isomers have the same molecular formula but different structural formulae. They can be chain isomers, position isomers or functional group isomers.

构造异构体具有相同分子式但不同结构式，可分为碳链异构、位置异构和官能团异构。

Stereoisomerism in AS organic chemistry is E/Z isomerism around a double bond. A C=C bond cannot rotate, so if each carbon atom carries two different groups, two arrangements exist. Assign priority by atomic number: higher priority on opposite sides is E, on the same side is Z.

AS有机化学中的立体异构是围绕双键的E/Z异构。C=C双键不能旋转，因此当每个双键碳连有两个不同基团时，会存在两种空间排列。按原子序数确定优先基团：较高优先基团在异侧为E构型，在同侧为Z构型。

Functional group	Suffix / prefix	Example
alkane	-ane	C₂H₆ ethane
alkene	-ene	C₂H₄ ethene
halogenoalkane	fluoro-, chloro-, bromo-, iodo-	CH₃CH₂Br bromoethane
alcohol	-ol	C₂H₅OH ethanol

---

2. Alkanes | 烷烃

Alkanes have the general formula CₙH₂ₙ₊₂. Each carbon atom is bonded to four other atoms by single sigma (σ) bonds, giving a tetrahedral arrangement with bond angles close to 109.5°.

烷烃的通式为CₙH₂ₙ₊₂。每个碳原子通过四个单键（σ键）与其他原子相连，呈四面体排布，键角接近109.5°。

Alkanes are obtained by fractional distillation of crude oil. Large hydrocarbon molecules with low value can be converted into smaller useful molecules by cracking, for example:

烷烃通过石油分馏获得。价值较低的大型烃分子可通过裂化转化为较小且有用的分子，例如：

C₁₀H₂₂ → C₈H₁₈ + C₂H₄

Alkanes burn in air to release energy. Complete combustion of methane forms CO₂ and H₂O; incomplete combustion forms CO or C and produces less energy.

烷烃在空气中燃烧释放能量。甲烷完全燃烧生成CO₂和H₂O；不完全燃烧会生成CO或碳，且释放能量较少。

Alkanes undergo free radical substitution with chlorine or bromine in the presence of ultraviolet light. The mechanism has three stages.

烷烃在紫外线照射下可与氯气或溴气发生自由基取代反应。该机理分为三个阶段。

Cl₂ → 2Cl• (initiation, UV light)

CH₄ + Cl• → •CH₃ + HCl (propagation)

•CH₃ + Cl₂ → CH₃Cl + Cl• (propagation)

Termination steps combine two radicals, for example Cl• + Cl• → Cl₂, •CH₃ + Cl• → CH₃Cl, and •CH₃ + •CH₃ → C₂H₆. In the exam, write ‘UV light’ as the condition and show all three stages clearly.

链终止步骤是两种自由基结合，例如Cl• + Cl• → Cl₂、•CH₃ + Cl• → CH₃Cl以及•CH₃ + •CH₃ → C₂H₆。考试中必须写明条件“紫外线”，并清晰写出三个阶段。

---

3. Halogenoalkanes | 卤代烷烃

Halogenoalkanes are classified as primary, secondary or tertiary according to the number of carbon atoms bonded to the carbon atom carrying the halogen.

卤代烷烃根据连接卤素的碳原子所连碳原子数分为伯、仲、叔卤代烷烃。

They undergo nucleophilic substitution because the carbon-halogen bond is polar. The halogen atom is slightly negative, and the carbon is slightly positive, so an electron-rich nucleophile attacks the carbon.

由于碳-卤素键具有极性，卤代烷烃可发生亲核取代。卤原子略带负电，碳原子略带正电，因此富电子的亲核试剂会进攻碳原子。

With aqueous sodium hydroxide, a halogenoalkane forms an alcohol:

与氢氧化钠水溶液反应，卤代烷烃生成醇：

C₂H₅Br + OH⁻ → C₂H₅OH + Br⁻

With ethanolic potassium cyanide, the product is a nitrile and the carbon chain is extended:

与乙醇氢氰酸钾? Actually ethanolic KCN 反应生成腈，碳链增长：

C₂H₅Br + CN⁻ → C₂H₅CN + Br⁻

With ammonia, the product is an amine:

与氨反应生成胺：

C₂H₅Br + 2NH₃ → C₂H₅NH₂ + NH₄Br

Halogenoalkanes can also undergo elimination. Using potassium hydroxide dissolved in ethanol, a hydrogen halide is removed and an alkene is formed:

卤代烷烃也能发生消除反应。使用溶于乙醇的氢氧化钾，脱去一分子卤化氢并生成烯烃：

C₂H₅Br + KOH (ethanolic) → C₂H₄ + KBr + H₂O

Chlorofluorocarbons (CFCs) are halogenoalkanes that deplete the ozone layer. In the stratosphere, UV light breaks a C-Cl bond to produce a chlorine radical, which destroys ozone in a chain reaction.

氯氟烃（CFCs）属于卤代烷烃，会破坏臭氧层。在平流层中，紫外线打断C-Cl键产生氯自由基，并通过链式反应破坏臭氧。

---

4. Alkenes | 烯烃

Alkenes have the general formula CₙH₂ₙ and contain a carbon-carbon double bond. The double bond consists of one sigma (σ) bond and one pi (π) bond. The pi bond has high electron density and makes alkenes reactive as electron donors.

烯烃通式为CₙH₂ₙ，含有碳碳双键。双键由一根σ键和一根π键组成。π键电子密度高，使烯烃具有电子供体的反应活性。

Alkenes undergo electrophilic addition reactions. The electrophile is attracted to the π electron cloud; the C=C bond breaks and two new single bonds are formed.

烯烃发生亲电加成反应。亲电试剂受π电子云吸引，C=C双键断裂并形成两根新的单键。

C₂H₄ + Br₂ → C₂H₄Br₂

C₂H₄ + HBr → C₂H₅Br

C₂H₄ + H₂O → C₂H₅OH (H₃PO₄ catalyst, high temperature and pressure)

The reaction of ethene with bromine water decolourises the orange solution to colourless. This is the standard test for unsaturation.

乙烯与溴水反应会使橙色溴水褪为无色，这是检验不饱和键的标准方法。

Alkenes also undergo addition polymerisation. Many ethene monomers join together to form poly(ethene):

烯烃还可发生加成聚合反应。大量乙烯单体连接形成聚乙烯：

n CH₂=CH₂ → [-CH₂-CH₂-]ₙ

---

5. Alcohols | 醇类

Alcohols contain the hydroxyl group, -OH. They can be classified as primary, secondary or tertiary depending on how many carbon groups are attached to the carbon bearing the -OH group.

醇类含有羟基-OH。根据与羟基碳相连的碳基团数目，醇可分为伯醇、仲醇和叔醇。

Alcohols burn in oxygen to form CO₂ and H₂O, and are useful as cleaner fuels than many hydrocarbons.

醇在氧气中燃烧生成CO₂和H₂O，且作为燃料比许多烃更清洁。

Primary, secondary and tertiary alcohols can be distinguished by oxidation with acidified potassium dichromate(VI), K₂Cr₂O₇. The orange dichromate is reduced to green Cr³⁺ if oxidation occurs.

使用酸化的重铬酸钾K₂Cr₂O₇可将伯醇、仲醇和叔醇区分开。若发生氧化，橙色重铬酸根被还原为绿色Cr³⁺。

Primary alcohols are oxidised first to aldehydes and then to carboxylic acids:

伯醇先被氧化为醛，再氧化为羧酸：

CH₃CH₂OH + [O] → CH₃CHO + H₂O

CH₃CHO + [O] → CH₃COOH

To isolate the aldehyde, distil the product out of the reaction mixture as it forms. To obtain the carboxylic acid, heat under reflux.

若要得到醛，应在生成的同时蒸馏出产物。若要得到羧酸，则需加热回流。

Secondary alcohols are oxidised to ketones:

仲醇氧化生成酮：

(CH₃)₂CHOH + [O] → (CH₃)₂CO + H₂O

Tertiary alcohols cannot be oxidised by acidified K₂Cr₂O₇, so the orange colour remains.

叔醇不能被酸性K₂Cr₂O₇氧化，因此溶液保持橙色。

Alcohols can be dehydrated to alkenes using concentrated H₂SO₄ or aluminium oxide:

醇可用浓硫酸或氧化铝脱水生成烯烃：

C₂H₅OH → C₂H₄ + H₂O

Alcohols react with phosphorus pentachloride, PCl₅, to produce a chloroalkane and steamy white fumes of HCl. This can be used as a test for the -OH group.

醇与五氯化磷P

Published by TutorHao | AS Revision Series | aleveler.com

更多咨询请联系16621398022（同微信）