📚 Apparatus and Reagents in IGCSE Chemistry | IGCSE 化学中的仪器与试剂
In IGCSE Chemistry, practical work depends on choosing the correct apparatus and reagent for each task. A successful experiment requires not only a clear method but also an understanding of what each piece of equipment is designed to do, how accurately it measures, and how to use it safely. This article covers the essential apparatus and reagents you will meet in the course, explains their correct use, and shows how exam questions often test practical reasoning.
在 IGCSE 化学中，实验工作取决于为每项任务选择正确的仪器和试剂。一个成功的实验不仅需要清晰的方法，还需要理解每件设备的设计用途、测量精度以及如何安全使用。本文涵盖课程中会接触到的主要仪器和试剂，解释正确用法，并说明考试题如何考查实验推理。
1. Why Choosing the Right Apparatus and Reagent Matters | 为什么选择正确的仪器与试剂很重要
Chemistry practicals are not only about following instructions. Every measurement, separation, heating step and chemical test depends on the apparatus and reagent being suitable for the purpose. For example, a beaker can hold a solution, but it cannot measure 25.0 cm³ accurately. A measuring cylinder is better than a beaker for rough volumes, while a pipette is required when a highly accurate fixed volume is needed.
化学实验不只是按步骤操作。每一次测量、分离、加热和化学检验，都取决于仪器和试剂是否适合该目的。例如，烧杯可以盛放溶液，但不能准确量取 25.0 cm³。量筒比烧杯更适合粗略量取体积，而当需要高度准确的固定体积时，则必须使用移液管。
Reagent choice is equally important. The same metal salt solution may be tested with sodium hydroxide solution to identify the cation, with silver nitrate solution to test for halide ions, or with barium chloride solution to test for sulfate ions. Choosing the wrong reagent gives no useful result, or even a misleading one.
试剂选择同样重要。同一金属盐溶液可以用氢氧化钠溶液检验阳离子，用硝酸银溶液检验卤素离子，或用氯化钡溶液检验硫酸根离子。选错试剂不会得到有用结果，甚至可能得到误导性结论。
2. Common Glassware and Basic Apparatus | 常用玻璃器具与基本仪器
Glassware is the backbone of most chemistry practical work. A beaker is a wide cylindrical container used for holding, mixing and roughly heating liquids; it is not designed for accurate volume measurement because its scale is only approximate. Beakers are ideal for dissolving solids, carrying out simple reactions and warming solutions on a tripod and gauze.
玻璃器具是大多数化学实验工作的基础。烧杯是一种宽圆柱形容器，用于盛放、混合和粗略加热液体；它不是为精确测量体积而设计的，因为其刻度仅为近似值。烧杯适合溶解固体、进行简单反应以及在三脚架和石棉网上加热溶液。
A conical flask has a narrow neck and a flat base, allowing liquids to be swirled without splashing. It is especially useful in titrations where mixing must occur while the flask stays stable. The narrow neck also reduces evaporation and helps prevent loss of solution during swirling.
锥形瓶瓶颈较窄、底部平坦，可在不飞溅的情况下摇动液体。它尤其适用于滴定，因为滴定中需要在锥形瓶保持稳定的同时进行混合。窄颈还能减少蒸发，并有助于防止摇动时溶液损失。
Other basic glassware includes test tubes for small-scale reactions, boiling tubes for stronger heating, watch glasses for evaporating tiny amounts of liquid, and evaporating basins for crystallisation. A volumetric flask is used to prepare a standard solution of exactly known concentration, such as 250.0 cm³ of 0.100 mol/dm³ sodium hydroxide solution.
其他基本玻璃器具有：用于小规模反应试管、用于较强加热的沸腾管、用于蒸发少量液体的表面皿，以及用于结晶的蒸发皿。容量瓶用于配制浓度精确已知的标准溶液，例如 250.0 cm³ 的 0.100 mol/dm³ 氢氧化钠溶液。
3. Measuring Volume: Burettes, Pipettes and Measuring Cylinders | 体积测量：滴定管、移液管与量筒
A burette is a long graduated tube with a tap at the bottom. It is used in titrations to deliver variable volumes of solution accurately, usually reading to the nearest 0.05 cm³. Before use, the burette should be rinsed with the solution it will contain, and the tap should be checked for leaks. Air bubbles must be removed from the tip.
滴定管是一种带旋塞的长刻度管。它用于滴定中准确放出可变体积的溶液，通常读到最近的 0.05 cm³。使用前，滴定管应用将要盛装的溶液润洗，并检查旋塞是否漏液。尖嘴处的气泡必须排出。
A pipette is used to deliver a single fixed volume accurately, commonly 25.0 cm³ or 20.0 cm³. It is filled using a pipette filler, never by mouth. A measuring cylinder is used for approximate volumes, such as 50 cm³ of water for a reaction, and should not be used when accurate titration data are required.
移液管用于准确放出单一固定体积，通常为 25.0 cm³ 或 20.0 cm³。它应使用洗耳球或移液管填充器吸取，绝不能用嘴吸。量筒用于近似体积，例如反应中量取 50 cm³ 水；当需要准确滴定数据时，不应使用量筒。
When reading the volume of a clear solution, read the bottom of the meniscus at eye level to avoid parallax error. For a dark solution, read the top of the meniscus. The volume used in a titration is calculated by:
读取无色溶液体积时，应平视凹液面最低处，以避免视差误差。对于深色溶液，读取凹液面最高处。滴定中使用的体积计算公式为：
Volume used = final reading − initial reading
4. Measuring Mass and Temperature | 质量与温度测量
A balance is used to measure mass. In school laboratories, a two-decimal-place balance reads to 0.01 g, while a three-decimal-place balance reads to 0.001 g. When weighing a solid, use a clean dry container or a weighing boat, and never place chemicals directly on the pan. The balance should be zeroed before use.
天平用于测量质量。在学校实验室中，两位小数天平读到 0.01 g，三位小数天平读到 0.001 g。称量固体时，应使用洁净干燥的容器或称量船，绝不能把化学药品直接放在托盘上。使用前应将天平归零。
A thermometer is used to measure temperature. A standard laboratory thermometer often reads from −10 °C to 110 °C, with scale divisions of 1 °C or 0.5 °C. For accurate temperature change experiments, the thermometer should be held in the liquid without touching the bottom or sides of the container.
温度计用于测量温度。标准实验室温度计通常量程为 −10 °C 到 110 °C，分度值为 1 °C 或 0.5 °C。对于准确的温度变化实验，温度计应浸入液体中，但不能接触容器底部或侧壁。
Temperature measurements are important in exothermic and endothermic reactions, neutralisation experiments and rates of reaction. A temperature rise of 5.0 °C may seem small, but if the thermometer is misread by 1 °C, the calculated energy change can be significantly affected.
温度测量在放热反应、吸热反应、中和实验和反应速率研究中很重要。5.0 °C 的温升看似不大，但如果温度计读数误差达到 1 °C，计算出的能量变化可能受到显著影响。
5. Heating, Mixing and Supporting Apparatus | 加热、搅拌与支撑仪器
A Bunsen burner is used for heating. The air hole should be adjusted to give a blue flame for strong heating or a yellow safety flame when not in use. A heatproof mat protects the bench, and a tripod with gauze supports a beaker or flask during heating. A clay triangle or pipeclay triangle supports a crucible during strong heating.
本生灯用于加热。应调节气孔，使火焰呈蓝色以进行强热，不使用时则调成黄色安全火焰。隔热垫保护实验台，三脚架和石棉网在加热时支撑烧杯或烧瓶。泥三角或管土三角用于在强热时支撑坩埚。
A retort stand, clamp and boss are used to hold apparatus safely, such as a burette during a titration or a condenser during distillation. Tongs are used to move hot crucibles or evaporating basins. A glass rod is used to stir solutions and to guide liquid when pouring.
铁架台、试管夹和十字夹用于安全固定仪器，例如滴定时的滴定管或蒸馏时的冷凝管。坩埚钳用于移动热坩埚或蒸发皿。玻璃棒用于搅拌溶液，并在倾倒液体时引流。
Mixing can be done with a glass rod or by swirling. A magnetic stirrer may be used when a reaction mixture needs continuous stirring, such as in a titration or a colorimetric experiment. Stirring increases the rate of dissolving and helps keep the temperature and concentration uniform.
混合可以用玻璃棒搅拌或摇动完成。当反应混合物需要持续搅拌时，例如滴定或比色实验，可以使用磁力搅拌器。搅拌可加快溶解速率，并有助于保持温度和浓度均匀。
6. Separation Techniques and Their Apparatus | 分离技术及其仪器
Filtration separates an insoluble solid from a liquid. The apparatus includes a filter funnel, filter paper, a beaker and a glass rod. The filter paper is folded and placed in the funnel, and the mixture is poured down the glass rod to prevent splashing. The liquid that passes through is the filtrate, and the solid left behind is the residue.
过滤用于将不溶性固体与液体分离。仪器包括过滤漏斗、滤纸、烧杯和玻璃棒。滤纸折叠后放入漏斗，混合物沿玻璃棒倒入以防止飞溅。穿过滤纸的液体是滤液，留在滤纸上的固体是残渣。
Crystallisation obtains a soluble solid from its solution. An evaporating basin is used to heat the solution gently until crystals begin to form, then the solution is left to cool and crystallise slowly. The crystals are separated by filtration and dried between filter papers or in a warm oven.
结晶用于从溶液中获得可溶性固体。使用蒸发皿温和加热溶液，直到开始形成晶体，然后让溶液冷却并缓慢结晶。晶体通过过滤分离，并在滤纸之间或温箱中干燥。
Simple distillation separates a solvent from a solution. The apparatus includes a distillation flask, a Liebig condenser, a thermometer, a receiver and a heat source. Fractional distillation uses a fractionating column to separate liquids with different boiling points, such as ethanol and water.
简单蒸馏用于将溶剂从溶液中分离。仪器包括蒸馏烧瓶、李比希冷凝管、温度计、接收器和热源。分馏使用分馏柱分离沸点不同的液体，例如乙醇和水。
Paper chromatography separates coloured substances using a chromatography paper, a solvent, and a capillary tube or pipette. A separating funnel is used to separate two immiscible liquids, such as oil and water, by draining the lower layer from the tap.
纸层析使用层析纸、溶剂和毛细管或移液管分离有色物质。分液漏斗用于分离两种不互溶液体，例如油和水，通过旋塞放出下层液体。
7. Reagents: Acids, Bases and Indicators | 试剂：酸、碱与指示剂
Common acids in IGCSE Chemistry include dilute hydrochloric acid, dilute sulfuric acid and dilute nitric acid. They are used in reactions with metals, bases, carbonates and salts. Dilute acids should be handled with care, and concentrated acids must be used in a fume cupboard with goggles and gloves.
IGCSE 化学中常见的酸包括稀盐酸、稀硫酸和稀硝酸。它们用于与金属、碱、碳酸盐和盐的反应。稀酸也应小心处理，浓酸必须在通风橱中佩戴护目镜和手套使用。
Common bases include sodium hydroxide solution, potassium hydroxide solution and ammonia solution. Sodium hydroxide is used in tests for metal cations and in titration with acids. Ammonia solution is used in tests for copper(II), iron(II) and iron(III) ions, and in gas tests for ammonia.
常见的碱包括氢氧化钠溶液、氢氧化钾溶液和氨水。氢氧化钠用于金属阳离子检验以及与酸的滴定。氨水用于铜(II)、铁(II)和铁(III)离子检验，以及氨气检验。
Indicators show whether a solution is acidic, alkaline or neutral. Litmus turns red in acid and blue in alkali. Methyl orange is red in acid and yellow in alkali. Phenolphthalein is colourless in acid and pink in alkali. Universal indicator gives a range of colours corresponding to pH values.
指示剂显示溶液是酸性、碱性还是中性。石蕊在酸中变红，在碱中变蓝。甲基橙在酸中为红色，在碱中为黄色。酚酞在酸中无色，在碱中为粉红色。通用指示剂给出对应 pH 值的多种颜色。
8. Salts, Solutions and Standard Reagents | 盐、溶液与标准试剂
Soluble salts can be prepared by reacting an acid with an insoluble base, metal or carbonate, then filtering off excess solid and crystallising the solution. Insoluble salts, such as barium sulfate, are prepared by precipitation. A precipitation reaction occurs when two solutions are mixed and an insoluble solid forms.
可溶性盐可通过酸与不溶性碱、金属或碳酸盐反应制备，然后过滤除去过量固体并使溶液结晶。不溶性盐，如硫酸钡，通过沉淀法制备。当两种溶液混合并形成不溶性固体时，就发生沉淀反应。
Silver nitrate solution is used to test for halide ions. Chloride gives a white precipitate, bromide gives a cream precipitate, and iodide gives a yellow precipitate. Barium chloride solution acidified with dilute hydrochloric acid is used to test for sulfate ions; a white precipitate of barium sulfate forms.
硝酸银溶液用于检验卤素离子。氯化物产生白色沉淀，溴化物产生奶油色沉淀，碘化物产生黄色沉淀。用稀盐酸酸化的氯化钡溶液用于检验硫酸根离子；会形成白色硫酸钡沉淀。
Limewater is used to test for carbon dioxide; it turns milky or cloudy. Anhydrous copper(II) sulfate turns from white to blue in the presence of water, and cobalt chloride paper turns from blue to pink. These reagents are used to test for water, not for a solution.
石灰水用于检验二氧化碳；它会变浑浊或乳白色。无水硫酸铜遇水由白色变蓝色，氯化钴试纸由蓝色变粉红色。这些试剂用于检验水，而不是检验溶液。
9. Gas Preparation and Testing Reagents | 气体制备与检验试剂
Oxygen can be prepared by the catalytic decomposition of hydrogen peroxide using manganese(IV) oxide. A gas syringe or inverted test tube can collect the gas. A glowing splint relights in oxygen. Hydrogen is prepared by reacting zinc with dilute hydrochloric acid, and a lighted splint gives a squeaky pop.
氧气可通过过氧化氢在二氧化锰催化下分解制备。可用气体注射器或倒置试管收集气体。带火星的木条在氧气中复燃。氢气由锌与稀盐酸反应制备，点燃的木条会发出爆鸣声。
Carbon dioxide is prepared by reacting marble chips with dilute hydrochloric acid. It is collected by downward delivery because it is denser than air. Limewater turns milky when carbon dioxide is bubbled through it. Ammonia is prepared by heating ammonium chloride with calcium hydroxide; damp red litmus paper turns blue.
二氧化碳由大理石碎块与稀盐酸反应制备。由于它比空气密度大，用向上排空气法收集。二氧化碳通入石灰水时，石灰水变浑浊。氨气由氯化铵与氢氧化钙加热制备；湿润的红色石蕊试纸变蓝。
Chlorine bleaches damp litmus paper. Sulfur dioxide turns acidified potassium dichromate(VI) paper from orange to green. These gas tests require careful use of a fume cupboard because the gases are toxic or irritating.
氯气会使湿润的石蕊试纸褪色。二氧化硫使酸化重铬酸钾(VI)试纸由橙色变绿色。这些气体检验需要在通风橱中小心进行，因为这些气体有毒或具刺激性。
10. Accuracy, Precision and Error | 准确度、精密度与误差
Accuracy refers to how close a measured value is to the true value. Precision refers to how close repeated measurements are to each other. A burette can give precise readings to 0.05 cm³, but if it is not rinsed correctly, the results may still be inaccurate because of systematic error.
准确度指测量值与真实值的接近程度。精密度指重复测量值之间的接近程度。滴定管可以给出精确到 0.05 cm³ 的读数，但如果未正确润洗，由于系统误差，结果仍可能不准确。
Random errors can be reduced by repeating measurements and taking an average. Systematic errors cannot be reduced by averaging; they require correcting the method, such as calibrating a balance, checking a thermometer, or using a clean burette. Parallax error is avoided by reading at eye level.
随机误差可通过重复测量并取平均值来减小。系统误差不能通过取平均值消除；需要校正方法，例如校准天平、检查温度计或使用洁净滴定管。视差误差可通过平视读数避免。
When recording measurements, use the correct number of decimal places. A burette reading should be recorded to two decimal places, such as 24.50 cm³, even if the second decimal is zero. A pipette volume is recorded as 25.0 cm³, and a balance reading as 2.50 g or 2.500 g depending on the balance.
记录测量值时，应使用正确的小数位数。滴定管读数应记录到两位小数，例如 24.50 cm³，即使第二位小数为零。移液管体积记为 25.0 cm³，天平读数根据天平精度记为 2.50 g 或 2.500 g。
11. Safety, Labelling and Waste Disposal | 安全、标签与废液处理
Safety is an essential part of practical chemistry. Goggles must be worn whenever chemicals are handled. A lab coat protects clothing and skin. Long hair should be tied back, and bags should be kept away from walkways. Food and drink are never allowed in the laboratory.
安全是实验化学的重要组成部分。处理化学品时必须佩戴护目镜。实验服保护衣物和皮肤。长发应束起，书包应远离通道。实验室中绝不允许饮食。
Hazard symbols on reagent bottles indicate the main danger. Corrosive substances attack skin and eyes. Toxic substances are poisonous if swallowed, inhaled or absorbed. Flammable substances catch fire easily. Oxidising agents can increase the risk of fire. Irritant substances cause soreness, and environmental hazard substances are harmful to living organisms.
试剂瓶上的危险符号表示主要危险。腐蚀性物质会侵蚀皮肤和眼睛。有毒物质若吞咽、吸入或吸收会中毒。易燃物质容易着火。氧化剂会增加火灾风险。刺激性物质会引起疼痛，环境危害物质对生物有害。
Waste should be disposed of as instructed. Acids and alkalis may be neutralised before disposal, but only under teacher supervision. Organic solvents must not be poured down the sink. Broken glass goes into a designated sharps bin, and unused chemicals should not be returned to the original bottle to avoid contamination.
废液应按指示处理。酸和碱可在教师监督下中和后处理。有机溶剂不得倒入水槽。碎玻璃应放入指定的尖锐物容器，未使用的化学品不应倒回原瓶，以免污染。
12. Exam-Style Questions on Apparatus and Reagents | 考试风格的仪器与试剂题
IGCSE exam questions often ask you to choose apparatus for a stated purpose. For example: 'Name the apparatus used to measure 25.0 cm³ of dilute hydrochloric acid accurately.' The answer is a pipette, because it delivers a fixed accurate volume. A measuring cylinder would only be suitable for approximate volumes.
IGCSE 考试题常要求你为特定目的选择仪器。例如：“写出准确量取 25.0 cm³ 稀盐酸所用仪器的名称。”答案是移液管，因为它能放出准确的固定体积。量筒只适合近似体积。
Another common question asks why a conical flask is used in a titration rather than a beaker. The answer should mention that the conical flask can be swirled without splashing, has a narrow neck that reduces evaporation and loss, and allows the end-point colour change to be seen clearly against a white tile.
另一个常见问题问：为什么滴定时使用锥形瓶而不是烧杯？答案应提到锥形瓶可以摇动而不飞溅，窄颈减少蒸发和损失，并且便于在白色瓷板上清楚观察终点颜色变化。
Questions may also ask for the reagent used to test for a particular ion or gas. Learn the expected observations, not just the reagent names. For example, 'silver nitrate solution' alone is incomplete; you should state 'add dilute nitric acid, then silver nitrate solution' and give the colour of the precipitate.
题目还可能问用于检验某种离子或气体的试剂。要记住预期现象，而不仅是试剂名称。例如，只写“硝酸银溶液”并不完整；应写“加入稀硝酸，然后加入硝酸银溶液”，并给出沉淀颜色。
Finally, practical questions often test safety. If a question asks why a fume cupboard is used, link it to toxic or irritating vapours. If it asks why a heatproof mat is used, link it to protecting the bench from heat. Precise practical vocabulary earns marks in IGCSE Chemistry.
最后，实验题常考查安全。如果问为什么使用通风橱，要联系有毒或刺激性蒸气。如果问为什么使用隔热垫，要联系保护实验台免受热损伤。精确的实验术语能在 IGCSE 化学中得分。
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