IGCSE CIE Chemistry: Essential Experimental Techniques for 0620 | IGCSE CIE 化学：0620 必备实验操作

📚 IGCSE CIE Chemistry: Essential Experimental Techniques for 0620 | IGCSE CIE 化学：0620 必备实验操作

Mastering laboratory techniques is vital for success in IGCSE CIE Chemistry 0620, not only for practical assessments but also for tackling theory questions that test your understanding of experimental procedures. From accurate measurement of volumes and masses to safe heating, separation methods, and gas handling, a solid grasp of these operations strengthens your ability to design experiments, interpret results, and avoid common errors. This article walks you through the core experimental skills required by the syllabus, pairing clear English explanations with their Chinese counterparts to support bilingual learners.

掌握实验操作技能对 IGCSE CIE 化学 0620 的成功至关重要，这不仅关乎实验考试，也有助于应对考察实验流程的理论题目。从精确测量体积和质量，到安全加热、分离方法以及气体操作，扎实掌握这些基本技能能让你更好地设计实验、解释结果并避免常见错误。本文带你梳理考纲要求的核心实验技能，以清晰的中英双语解释帮助双语学习者理解和记忆。

1. Measuring Volumes and Masses Accurately | 精确测量体积与质量

When measuring liquid volumes, choosing the right apparatus is essential. A measuring cylinder offers moderate accuracy (±0.5 cm³ for a 100 cm³ cylinder) and is suitable for approximate volumes. For high precision, use a pipette to transfer a fixed volume (e.g. 25.0 cm³) or a burette for delivering variable volumes with readings to ±0.05 cm³.

测量液体体积时，选择合适的仪器至关重要。量筒准确度适中（100 cm³ 量筒误差约 ±0.5 cm³），适用于粗略量取。要获得高精度，需用移液管转移固定体积（如 25.0 cm³），或用滴定管提供可变体积的读数，精度可达 ±0.05 cm³。

When weighing solids, an electronic balance is the standard tool. Always place a weighing boat or paper on the pan, press the tare button to zero the reading, then add the solid. Record the mass to at least 0.01 g if the balance permits. Avoid touching chemicals directly with bare hands, and never return unused reagent to the original container.

称量固体时，电子天平是标准工具。务必在称盘上放置称量舟或称量纸，按去皮键归零，然后加入固体。若天平允许，记录质量时应至少保留 0.01 g。避免用手直接接触化学药品，切勿将未用试剂倒回原瓶。

2. Using Common Laboratory Apparatus | 常见实验器材的使用

Familiarity with everyday glassware and hardware prevents mistakes. A beaker is useful for mixing, heating, and holding liquids but is not calibrated for precise measurement. Conical flasks are ideal for titrations because swirling can be done without spillage. A volumetric flask is designed to prepare solutions of an exact known concentration; after dissolving the solute, distilled water is added until the bottom of the meniscus sits exactly on the graduation mark.

熟悉日常玻璃器皿和器材可避免操作失误。烧杯适用于混合、加热与盛装液体，但未校准精确体积。锥形瓶因摇匀时不易溅出，非常适合滴定实验。容量瓶专用于配制精确浓度的溶液；将溶质溶解后，加入蒸馏水直至弯月面底部恰好与刻度线相切。

A Bunsen burner provides a controllable flame: the air hole adjusts the supply of oxygen, producing a yellow safety flame when closed and a noisy blue flame when open. A tripod and gauze support beakers during heating, while a heat‑proof mat protects the bench. A clay‑pipe triangle placed on a tripod is used when heating crucibles strongly.

本生灯提供可控火焰：调节空气孔可改变氧气供应量，空气孔关闭时产生黄色安全焰，打开则产生喧嚣的蓝色高温焰。三脚架和陶土网用于在加热时支撑烧杯，隔热垫保护实验台。用泥三角架在三脚架上可对坩埚进行强热。

3. Heating Methods: Bunsen Burner and Water Bath | 加热方法：本生灯和水浴

Direct heating with a Bunsen burner is suitable for non‑flammable liquids and solids. The blue roaring flame is placed under a tripod and gauze, and the object is heated from below. Always point the mouth of a test tube away from yourself and others, and move the tube continuously through the flame to avoid bumping. For flammable organic solvents, never use a naked flame; instead, use a water bath or an electric heater.

使用本生灯直接加热适用于不易燃的液体和固体。将蓝色喧腾焰置于三脚架和陶土网下方，从底部加热。加热试管时应使管口远离自己和他人，并在火焰上不断移动试管以防暴沸。对于易燃有机溶剂，绝对不可使用明火，应改用水浴或电热器。

A water bath consists of a beaker of water heated by a Bunsen burner or electric hotplate. It provides gentle, uniform heating up to 100°C and prevents local overheating. The sample container is placed in the water bath, not directly on the heat source. This method is essential for evaporating solvents from thermally sensitive substances or for maintaining a constant temperature during rate experiments.

水浴是由装有水的烧杯通过本生灯或电热板加热而成，能提供最高 100 °C 的温和、均匀加热，避免局部过热。样品容器放入水浴中，而非直接接触热源。此法对于蒸发热敏性物质的溶剂，或在速率实验中保持恒温是不可或缺的。

4. Filtration and Evaporation Techniques | 过滤与蒸发技术

Filtration separates an insoluble solid from a liquid. Fold a filter paper into a cone and place it in a filter funnel that sits in a conical flask or beaker. Pour the mixture along a glass rod into the funnel to prevent splashing. The residue collects on the paper while the filtrate passes through. To obtain a dry sample of the residue, rinse it with a little distilled water and allow it to dry in air or in a low‑temperature oven.

过滤用于分离不溶性固体与液体。将滤纸折叠成锥形放入漏斗，漏斗置于锥形瓶或烧杯上。沿玻璃棒将混合物倒入漏斗，以防飞溅。残留物留存在滤纸上，滤液则通过滤纸。要获得干燥的残留物样品，用少量蒸馏水冲洗后在空气中晾干或低温烘干。

Evaporation is used to obtain a soluble solid from a solution. Pour the solution into an evaporating basin and heat gently over a water bath or a low Bunsen flame. Stop heating when a saturated solution forms (crystals just begin to appear at the edge) and allow the remainder to crystallise slowly at room temperature. Direct strong heating to dryness can cause spitting and decomposition of some salts.

蒸发用于从溶液中获取可溶性固体。将溶液倒入蒸发皿，在水浴或微火下缓慢加热。当溶液达到饱和（边缘刚开始出现晶体）时停止加热，让剩余溶液在室温下缓慢结晶。直接强热至干会导致液体飞溅及某些盐类分解。

5. Distillation and Fractional Distillation | 蒸馏与分馏

Simple distillation is used to separate a pure liquid from a solution (e.g. pure water from salt water). The mixture is heated in a round‑bottom flask fitted with a thermometer at the neck and a condenser sloping downwards. The liquid boils, vapour travels into the condenser and is cooled back to liquid, which is collected as distillate. The thermometer bulb must be placed at the neck opening to measure the boiling point of the vapour accurately.

简单蒸馏用于从溶液中分离纯液体（如从盐水中获得纯水）。混合物在圆底烧瓶中加热，烧瓶支管处连接温度计，并接入向下倾斜的冷凝管。液体沸腾后蒸气进入冷凝管被冷却成液体，收集为馏出液。温度计水银球必须置于支管开口处，以准确测量蒸气的沸点。

Fractional distillation separates two or more miscible liquids with different boiling points (e.g. ethanol and water). A fractionating column packed with glass beads or a fractionating spiral is inserted between the flask and the condenser. The vapour mixture undergoes repeated condensation and vaporisation inside the column, enriching the more volatile component. The thermometer reading rises first to the lower boiling point, and the fraction is collected; as the temperature rises to the next boiling point, the receiver is changed.

分馏用于分离两种或多种沸点不同的互溶液体（如乙醇和水）。在烧瓶与冷凝管之间插入装有玻璃珠或分馏螺环的分馏柱。蒸气混合物在柱内经历反复冷凝和蒸发，使更易挥发的组分不断富集。温度计读数首先升至较低的沸点并收集该馏分；当温度升至下一沸点时，更换接收器。

6. Paper Chromatography: Principles and Procedure | 纸色谱法：原理与步骤

Paper chromatography separates small amounts of substances based on their differential partitioning between a stationary phase (water adsorbed on paper) and a mobile phase (a suitable solvent). A baseline is drawn in pencil (not pen, as ink would dissolve) about 2 cm from the bottom edge. Tiny spots of sample solutions are placed on the line, the paper is suspended in a beaker so that the solvent level is below the spots, and the beaker is covered to maintain a saturated solvent atmosphere.

纸色谱法基于物质在固定相（吸附在纸上的水分）与流动相（合适溶剂）之间分配系数的不同而实现微量物质的分离。用铅笔（非墨水笔，因墨迹会溶解）在距纸边缘约 2 cm 处画基线，在线上点加微量样品溶液。将纸悬挂于烧杯中，使溶剂液面低于样点，并盖上烧杯以维持饱和溶剂气氛。

As the solvent rises, components travel at different rates. The plate is removed when the solvent front nears the top, and the positions of the colourless spots are marked under UV light or by spraying a locating agent. The retention factor (R_f) is calculated as distance moved by spot divided by distance moved by solvent front; this value is characteristic for a given component under identical conditions.

溶剂上升时各组分移动速率不同。当溶剂前沿接近顶端时取出纸片，无色斑点在紫外灯下或通过喷洒显色剂后标记位置。比移值 (R_f) 的计算为斑点移动距离除以溶剂前沿移动距离；该值在相同实验条件下对特定组分具有特征性。

7. Preparing and Collecting Gases | 气体的制备与收集

Gases are commonly prepared in the laboratory by reactions such as an acid with a carbonate (CO₂), an acid with a reactive metal (H₂), or the decomposition of hydrogen peroxide with manganese(IV) oxide (O₂). The reaction is carried out in a side‑arm boiling tube or flask fitted with a delivery tube. The choice of gas collection method depends on the gas’s density relative to air and its solubility in water.

实验室通常通过酸与碳酸盐反应制 CO₂、酸与活泼金属反应制 H₂、或过氧化氢在二氧化锰催化下分解制 O₂ 来制备气体。反应在配有导气管的支管试管或烧瓶中进行。气体收集方法的选择取决于气体相对于空气的密度及其在水中的溶解度。

The three principal collection methods are:

Upward delivery – for gases denser than air and soluble in water, e.g. chlorine, hydrogen chloride.
Downward delivery – for gases less dense than air and soluble in water, e.g. ammonia.
Over water – for gases that are only slightly soluble in water and whose density does not matter, e.g. oxygen, hydrogen.

三种主要收集方法为：

向上排空气法 – 用于密度大于空气且溶于水的气体，如氯气、氯化氢。
向下排空气法 – 用于密度小于空气且溶于水的气体，如氨气。
排水集气法 – 用于难溶于水、密度无限制的气体，如氧气、氢气。

Testing the purity of hydrogen, for example, involves collecting a small sample in a test tube and holding it near a flame: a squeaky pop indicates pure hydrogen, while a loud explosive pop indicates the presence of air.

检验氢气纯度时，可收集一小试管气体并移近火焰：听到轻微的“噗”声则气体纯净，尖锐的爆鸣声表明混有空气。

8. Drying Gases and Testing for Common Gases | 气体的干燥及常见气体检验

Before certain tests or when a dry gas is required, moisture must be removed. Common drying agents include:

Drying Agent	Suitable for	Unsuitable for
Concentrated sulfuric acid	Most gases (acidic, neutral, O₂, H₂, Cl₂, etc.)	Ammonia (acid–base reaction)
Anhydrous calcium chloride	Most neutral and acidic gases	Ammonia (forms complex)
Quicklime (calcium oxide)	Ammonia	Acidic gases (e.g. CO₂, HCl)

在某些测试前或需要干燥气体时，必须除去水分。常见干燥剂如下：

干燥剂	适用气体	不适用气体
浓硫酸	大多数气体（酸性、中性、O₂、H₂、Cl₂ 等）	氨气（酸碱反应）
无水氯化钙	大多数中性与酸性气体	氨气（形成络合物）
生石灰（氧化钙）	氨气	酸性气体（如 CO₂、HCl）

The following confirmatory tests are essential knowledge:

Carbon dioxide – bubble through limewater; turns it milky.
Oxygen – relights a glowing splint.
Hydrogen – extinguishes a lighted splint with a ‘squeaky pop’.
Ammonia – turns damp red litmus paper blue.
Chlorine – bleaches damp blue litmus paper.

以下确证性检验为必备知识：

二氧化碳 – 通入石灰水；石灰水变浑浊。
氧气 – 可使带火星的木条复燃。
氢气 – 点燃的木条靠近时发出“噗”声并熄灭。
氨气 – 使湿润的红色石蕊试纸变蓝。
氯气 – 漂白湿润的蓝色石蕊试纸。

9. Acid–Base Titration Technique | 酸碱滴定技术

Titration is a quantitative technique to determine the concentration of an acid or base using a standard solution. A pipette is used to transfer a known volume of the unknown solution into a conical flask, and a few drops of indicator (e.g. phenolphthalein or methyl orange) are added. The burette is filled with the standard solution and the initial reading is recorded to ±0.05 cm³, with the eye at the same level as the bottom of the meniscus.

滴定是一种定量技术，利用标准溶液测定酸或碱的浓度。用移液管将已知体积的待测液移入锥形瓶，加入几滴指示剂（如酚酞或甲基橙）。滴定管充入标准溶液，视线与弯月面底部保持水平，记录初始读数，精度为 ±0.05 cm³。

The standard solution is added slowly while swirling the flask continuously. Near the end point a partial drop is often used. At the end point the colour change persists after swirling; final burette reading is recorded. The titration is repeated until two concordant titres (within 0.10 cm³) are obtained, and the average is used for calculation. The titre is simply final burette reading minus initial reading.

在持续摇荡锥形瓶的同时缓慢加入标准溶液。接近终点时常采用半滴操作。终点时摇匀后颜色变化稳定，记录滴定管终读数。重复滴定直至获得两次符合误差范围（≤0.10 cm³）的滴定值，取平均值用于计算。滴定体积即为终读数减初读数。

10. Measuring Rates of Reaction | 反应速率的测定

The rate of a reaction can be followed by measuring the change in mass, the volume of gas evolved, or the time taken for a visible change such as the appearance of a precipitate. For reactions that produce a gas, a gas syringe or an inverted measuring cylinder over water can record the volume at regular time intervals. Plotting volume against time gives a curve whose gradient indicates the rate at any moment.

反应速率可通过测量质量变化、逸出气体体积或可见变化（如沉淀出现）所需的时间来跟踪。对于产生气体的反应，可使用气体注射器或倒扣在水中的量筒每隔一定时间记录气体体积。以体积对时间作图得到一条曲线，曲线斜率代表任意时刻的速率。

When investigating the effect of concentration on rate (e.g. reaction of sodium thiosulfate with hydrochloric acid), the mixture is placed over a black cross marked on paper. The time for the cross to disappear due to the formation of a sulfur precipitate is recorded. The rate is proportional to 1/time. Temperature, particle size, and catalyst are other common variables investigated by simple experiments, each requiring careful control of all other conditions to ensure fair testing.

在探究浓度对速率的影响时（如硫代硫酸钠与盐酸的反应），将混合物置于画有黑十字的纸上，记录因硫沉淀生成导致十字消失所需的时间。速率与 1/时间成正比。温度、颗粒大小和催化剂是其他常见的变量，均可通过简单实验探究，但必须严格控制其余所有条件以确保公平测试。

11. Testing for Cations, Anions and pH | 阳离子、阴离子及 pH 的检测

Flame tests are used to identify certain metal cations: lithium gives a crimson‑red flame, sodium a yellow flame, potassium a lilac flame, calcium an orange‑red flame, and copper a blue‑green flame. A clean nichrome or platinum wire is dipped in concentrated HCl, then in the sample, and held in the edge of a roaring Bunsen flame.

焰色试验用于鉴定特定金属阳离子：锂呈深红色，钠呈黄色，钾呈淡紫色，钙呈橙红色，铜呈蓝绿色。将洁净的镍铬丝或铂丝蘸取浓盐酸，再蘸取样品，置于喧腾焰边缘灼烧观察。

Precipitation reactions with sodium hydroxide solution help identify further cations in aqueous solutions:

Cu²⁺ gives a blue precipitate.
Fe²⁺ gives a green precipitate that turns brown on standing.
Fe³⁺ gives a reddish‑brown precipitate.
Zn²⁺ gives a white precipitate, soluble in excess NaOH.
Al³⁺ also gives a white precipitate, soluble in excess NaOH (distinction can be made by further tests).
Ca²⁺ gives a white precipitate, insoluble in excess NaOH.

向水溶液中加入氢氧化钠溶液产生沉淀，可进一步鉴定阳离子：

Cu²⁺ 生成蓝色沉淀。
Fe²⁺ 生成绿色沉淀，放置后变褐。
Fe³⁺ 生成红褐色沉淀。
Zn²⁺ 生成白色沉淀，溶于过量 NaOH。
Al³⁺ 同样生成白色沉淀，溶于过量 NaOH（可通过进一步实验区分）。
Ca²⁺ 生成白色沉淀，不溶于过量 NaOH。

Common anion tests include:

Carbonate (CO₃²⁻): add dilute acid; effervescence of CO₂ confirmed by limewater.
Halide ions (Cl⁻, Br⁻, I⁻): add silver nitrate solution acidified with dilute nitric acid; white (AgCl), cream (AgBr), or yellow (AgI) precipitate formed.
Sulfate (SO₄²⁻): add barium chloride solution acidified with dilute HCl; white precipitate of BaSO₄.
Nitrate (NO₃⁻): add aluminium powder and sodium hydroxide solution, warm; ammonia gas released turns red litmus blue.

常见阴离子检验包括：

碳酸根 CO₃²⁻：加入稀酸，产生使石灰水变浑浊的 CO₂ 气体。
卤离子（Cl⁻, Br⁻, I⁻）：加入经稀硝酸酸化的硝酸银溶液，生成白色 (AgCl)、奶油色 (AgBr) 或黄色 (AgI) 沉淀。
硫酸根 SO₄²⁻：加入经稀盐酸酸化的氯化钡溶液，生成白色 BaSO₄ 沉淀。
硝酸根 NO₃⁻：加入铝粉和氢氧化钠溶液并加热，释放的氨气使红色石蕊试纸变蓝。

Universal indicator paper or a pH probe can determine the acidity or alkalinity of a solution. The colour is matched against a pH chart; a value below 7 indicates acidic, 7 neutral, and above 7 alkaline. Always use clean, dry glassware to avoid contamination.

广泛 pH 试纸或 pH 探头可测定溶液的酸碱度。将颜色与比色卡对照，pH 小于 7 为酸性，等于 7 为中性，大于 7 为碱性。务必使用洁净干燥的玻璃器皿以避免污染。

12. Safety Practices and Key Considerations | 安全操作与关键注意事项

Safety in the chemistry laboratory is a priority. Always wear safety goggles and, when handling corrosive chemicals, a lab coat and protective gloves. Tie back long hair and avoid loose clothing. Work in a well‑ventilated area or fume cupboard when using toxic or volatile substances such as chlorine or concentrated ammonia. Know the location of the nearest fire extinguisher, sand bucket, and eye‑wash station.

化学实验室安全是头等大事。始终佩戴护目镜，处理腐蚀性化学品时还需穿着实验服和防护手套。扎起长发，避免穿着宽松衣物。使用氯气或浓氨水等有毒或挥发性物质时应在通风橱中操作。应知晓最近的灭火器、沙桶和洗眼器的位置。

When heating a test tube, never point the open end at anyone. Use a test tube holder and heat the tube gently while moving it continuously. Always dilute concentrated acids by adding the acid slowly to water, never the reverse, to avoid violent spattering. Dispose of chemical waste according to your teacher’s instructions; never pour hazardous substances down the sink without permission. Label all solutions and solids clearly, and clean up any spillages immediately.

加热试管时，切勿将管口对准任何人。使用试管夹，边移动试管边温和加热。稀释浓酸时必须将酸缓慢加入水中，绝不可反向操作，以免剧烈飞溅。按教师指导处置化学废弃物，未经许可不得将有害物质倒入水槽。清晰标记所有溶液和固体，发生泄漏应立即清理。

Finally, always plan your experiment thoroughly, record observations in ink, and analyse uncertainties. Repeat measurements where possible to improve reliability. A clear method statement and labeled diagrams in your theory answers demonstrate deep understanding of experimental work.

最后，每次实验前应透彻规划，用墨水笔记录观察结果并分析误差。尽可能重复测量以提高可靠性。在理论作答中给出清晰的步骤描述和带有标注的示意图，能体现对实验操作的深刻理解。

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IGCSE CIE Chemistry: Essential Experimental Techniques for 0620 | IGCSE CIE 化学：0620 必备实验操作