Chemistry Experiment Exam Points: Common Instruments & Basic Operations | 化学实验考点：常用仪器与基本操作

📚 Chemistry Experiment Exam Points: Common Instruments & Basic Operations | 化学实验考点：常用仪器与基本操作

Mastering laboratory instruments and fundamental operations is essential for success in any chemistry examination. This guide systematically covers the apparatus you must recognise, their correct usage, and the procedural skills examiners frequently test.

掌握实验室常用仪器和基本操作是化学考试取得高分的关键。本指南系统梳理了考试中必须认识的仪器、它们的正确使用方法，以及考官常考的操作技能考点。

1. Measuring Instruments: Precision Matters | 计量仪器：精度至关重要

Precision in measurement is the foundation of reliable experimental data. Each measuring instrument has a specific degree of accuracy, and selecting the appropriate one demonstrates scientific competence.

精确测量是获得可靠实验数据的基础。每一种计量仪器都有特定的精度等级，选择恰当的仪器体现了科学素养。

Burette (滴定管) – Used for delivering variable volumes of liquid during titrations. It has a precision of ±0.05 cm³, with a typical capacity of 50.00 cm³. The reading should be taken from the bottom of the meniscus at eye level.

滴定管（Burette） – 用于滴定过程中逐量加入液体。精度为 ±0.05 cm³，常见容量为 50.00 cm³。读数时需平视弯月面底部。

Pipette (移液管) – Delivers a fixed volume accurately, typically 10.00 or 25.00 cm³, with precision ±0.05 cm³. Always rinse with the solution to be used and never blow out the last drop unless marked “to deliver”.

移液管（Pipette） – 准确转移固定体积的液体，常见规格为 10.00 或 25.00 cm³，精度 ±0.05 cm³。使用前需用待取液润洗，除非标有”吹出”记号，否则不可吹出最后一滴。

Volumetric Flask (容量瓶) – Used for preparing precise standard solutions. The graduation line indicates the exact volume at a specified temperature (usually 20 °C). Never heat a volumetric flask or store solutions in it.

容量瓶（Volumetric Flask） – 用于配制精确的标准溶液。刻度线标示在特定温度（通常 20 °C）下的准确体积。切勿加热容量瓶或在其中长期储存溶液。

Measuring Cylinder (量筒) – Suitable for approximate volume measurements (±0.5 cm³). It is less precise than a pipette or burette but convenient for general use.

量筒（Measuring Cylinder） – 适用于粗略量取体积（±0.5 cm³）。精度不如移液管或滴定管，但日常使用便捷。

2. Heating Apparatus: Energy Control | 加热装置：能量控制

Heating is one of the most common operations in chemistry, and each heating device serves a distinct purpose depending on the temperature required and the nature of the substance.

加热是化学实验中最常见的操作之一，每种加热设备因所需温度和物质性质的不同而各有用途。

Bunsen Burner (本生灯): Provides a high-temperature flame (up to 1500 °C). The blue flame is the hottest and is used for heating crucibles; the yellow, luminous flame is cooler and used for observation. 提供高温火焰（最高 1500 °C）。蓝色火焰温度最高，用于加热坩埚；黄色发光火焰温度较低，用于观察。
Electric Heater / Hot Plate (电热板): Safer for flammable solvents as there is no open flame. 电热板无明火，加热易燃溶剂时更安全。
Water Bath (水浴): Maintains temperatures below 100 °C, ideal for heating heat-sensitive substances or evaporating extracts without decomposition. 保持低于 100 °C 的温度，适用于加热热敏物质或蒸发萃取液而不致分解。
Oil Bath (油浴): Achieves temperatures between 100 °C and 250 °C with uniform heating. 可达到 100 °C 至 250 °C 的均匀加热温度。

When heating a test tube, always hold it at an angle, point the mouth away from yourself and others, and move it gently through the flame to ensure even heating.

加热试管时，应倾斜持握，试管口勿朝向自己或他人，并在火焰中缓慢移动以保证均匀受热。

3. Glassware Essentials: Vessels and Containers | 玻璃器皿要点：容器与反应器

Understanding the function of each glass container prevents experimental errors and accidents. Beakers, conical flasks, and round-bottom flasks each have unique design features.

了解每种玻璃容器的功能可以避免实验误差和事故。烧杯、锥形瓶和圆底烧瓶各有独特的设计特点。

Beaker (烧杯): Used for mixing, dissolving, and approximate volume measurements. Its wide mouth facilitates stirring and pouring, but it is not suitable for precise volume determination.

烧杯（Beaker）: 用于混合、溶解和粗略量取体积。宽口设计便于搅拌和倾倒，但不适合精确量取体积。

Conical Flask / Erlenmeyer Flask (锥形瓶): The narrow neck prevents splashing and reduces evaporation. It is the preferred vessel for titration receiving flasks because swirling is easy without spillage.

锥形瓶（Conical Flask / Erlenmeyer Flask）: 窄颈设计防止液体飞溅并减少蒸发。锥形瓶是滴定中盛接液体的首选容器，旋转摇动方便且不易洒出。

Round-Bottom Flask (圆底烧瓶): Designed for uniform heating and reflux setups. It withstands pressure differences better than flat-bottomed vessels, making it essential for distillation and synthesis reactions.

圆底烧瓶（Round-Bottom Flask）: 专为均匀加热和回流装置设计。其耐压性能优于平底容器，是蒸馏和合成反应的关键器材。

Watch Glass (表面皿): Used for evaporation of small amounts of solution, covering beakers, and holding solids during weighing. It is not a reaction vessel.

表面皿（Watch Glass）: 用于少量溶液的蒸发、覆盖烧杯以及称量时盛放固体。不可作为反应容器使用。

4. Separation Techniques: Filtration and Beyond | 分离技术：过滤与进阶方法

Separation is a core experimental skill. The choice of technique depends on the physical state of the mixture and the desired component’s properties.

分离操作是核心实验技能。技术选择取决于混合物的物理状态和目标组分的性质。

Filtration (过滤): Separates an insoluble solid from a liquid. Use a filter funnel lined with filter paper, ensuring the paper is moistened and fits snugly against the funnel walls. The filtrate should run down the glass rod when

过滤（Filtration）: 用于分离不溶性固体与液体。使用垫有滤纸的漏斗，确保滤纸润湿并紧贴漏斗壁。玻璃棒引流，使滤液沿棒流下。

Technique \| 技术	Separation Basis \| 分离原理	Typical Use \| 典型用途
Filtration / 过滤	Particle size / 颗粒大小	Solid-liquid separation / 固液分离
Crystallisation / 结晶	Solubility difference / 溶解度差异	Obtaining pure solids from solution / 从溶液中获取纯固体
Distillation / 蒸馏	Boiling point difference / 沸点差异	Separating miscible liquids / 分离互溶液体
Solvent Extraction / 萃取	Partition coefficient / 分配系数	Isolating a solute from aqueous solution / 从水溶液中分离溶质

5. Titration Equipment Setup | 滴定装置搭建

Titration is among the most frequently examined practical skills. Correct assembly and technique directly affect the accuracy of the endpoint determination.

滴定是最常考查的实验技能之一。装置搭建的正确性和操作技术直接影响终点判断的准确性。

Step 1 – Cleaning: Rinse the burette with distilled water followed by the titrant solution. The pipette must be rinsed with the solution it will deliver. Do not rinse the conical flask with either solution, as this would add extra moles of analyte.

第一步 – 清洗: 滴定管先用蒸馏水润洗，再用滴定剂润洗。移液管需用待取溶液润洗。锥形瓶不可用任何溶液润洗，否则会引入额外的溶质量。

Step 2 – Filling and Removing Air: Fill the burette above the zero mark, then open the tap briefly to expel air from the jet. Record the initial reading to two decimal places, e.g., 0.00 cm³.

第二步 – 装液与排气: 将滴定管液面加至零刻度以上，快速开启旋塞排出尖嘴中的气泡。初始读数记录至两位小数，如 0.00 cm³。

Step 3 – Titration: Add the titrant in a steady stream while swirling the conical flask. Near the endpoint, add dropwise. The endpoint is indicated by a permanent colour change – the indicator colour persists for at least 30 seconds.

第三步 – 滴定: 边旋转锥形瓶边匀速加入滴定剂。接近终点时改为逐滴加入。终点以颜色持续变化为标志——指示剂颜色至少保持 30 秒不褪。

Percentage Error = (Uncertainty of apparatus ÷ Measured volume) × 100%
百分误差 =（仪器不确定度 ÷ 测量体积）× 100%

6. Weighing Procedures: Balance Techniques | 称量操作：天平技术

Accurate weighing is critical for stoichiometric calculations. Digital balances are standard, but their correct use requires attention to several details.

准确称量对化学计量计算至关重要。电子天平是标准设备，但正确使用需要注意多个细节。

Zeroing (归零): Always tare the balance with the weighing container before adding the substance. 称量前务必放入容器并归零。
Weighing Boat / Paper (称量舟/称量纸): Use a clean, dry container; do not place chemicals directly on the balance pan. 使用清洁干燥的容器，切勿将化学品直接放在称量盘上。
Spatula (药匙): Transfer solids using a clean, dry spatula. Different chemicals require different spatulas to prevent contamination. 使用洁净干燥的药匙转移固体。不同化学品需用不同药匙以防污染。
Hygroscopic Substances (易潮解物质): Weigh quickly in a covered vessel to minimise moisture absorption. 易潮解物质应在加盖容器中快速称量，以减少吸湿。
Corrosive Gases (腐蚀性气体): Use a fume cupboard when weighing substances that release harmful vapours. 称量释放有害蒸气的物质时应在通风橱内进行。

For a digital balance with uncertainty ±0.01 g, the error is negligible when masses exceed 1 g. However, for small masses (e.g., 0.05 g), the relative error becomes significant.

对于不确定度为 ±0.01 g 的电子天平，当质量超过 1 g 时误差可忽略；但对于小质量（如 0.05 g），相对误差则非常显著。

7. Drying and Desiccation | 干燥与除湿

Removing moisture from solids or protecting hygroscopic materials requires specific apparatus and techniques. Examiners often ask about the choice of desiccant.

去除固体中的水分或保护易吸湿材料需要使用特定设备和技巧。考官常考查干燥剂的选择问题。

Desiccator (干燥器): A sealed glass container with a desiccant (such as anhydrous calcium chloride or silica gel) in the lower compartment. The ground-glass lid, greased with Vaseline, ensures an airtight seal. Hot objects must cool slightly before being placed inside, as a sudden vacuum could crack the glass.

干燥器（Desiccator）: 一种密封玻璃容器，下层装有干燥剂（如无水氯化钙或硅胶）。磨砂玻璃盖涂凡士林以确保密封。热物体须稍冷却后再放入，否则突然形成的真空可能导致玻璃破裂。

Oven Drying (烘箱干燥): Suitable for heat-stable solids. Set the oven between 100–110 °C for routine drying. Substances that sublime or decompose at this temperature cannot be dried this way.

烘箱干燥（Oven Drying）: 适用于热稳定固体。常规干燥温度设定在 100–110 °C。在此温度下会升华或分解的物质不可用此法。

Desiccant Selection: Anhydrous calcium chloride removes water effectively but cannot dry ammonia or alcohols. Concentrated sulfuric acid is a powerful desiccant but is hazardous. Silica gel with a cobalt indicator changes from blue to pink when saturated.

干燥剂选择: 无水氯化钙除水效果好，但不能用于干燥氨气或醇类。浓硫酸是强效干燥剂但危险性高。含钴指示剂的硅胶吸湿后由蓝色变为粉色。

8. Safety Equipment and Emergency Procedures | 安全设备与应急处理

Examiners frequently test knowledge of safety equipment and the correct response to laboratory accidents. This knowledge is as important as the experimental technique itself.

考官经常考查安全设备知识及实验室事故的正确应对措施。这些知识与实践技能同等重要。

Equipment / Equipment	Function / 功能	Exam Tip / 考试提示
Safety goggles / 护目镜	Protect eyes from splashes / 防止液体飞溅伤眼	Always worn, never removed mid-experiment / 全程佩戴，不得中途摘下
Fume cupboard / 通风橱	Removes toxic or volatile vapours / 排出有毒或挥发性蒸气	Used for chlorine, bromine, SO₂ / 用于氯气、溴、SO₂ 等实验
Fire blanket / 灭火毯	Smothers clothing fires / 扑灭衣物火焰	Wrap around the victim, not using water / 包裹伤者，不可用水
Eyewash station / 洗眼器	Flushes chemicals from eyes / 冲洗眼中化学品	Hold eyelids open, flush for 15 minutes / 撑开眼睑冲洗 15 分钟

Acid Spills: Neutralise with sodium hydrogencarbonate (NaHCO₃) solution, then wipe and rinse with water. For alkali spills, use dilute acetic acid or boric acid solution.

酸液泄漏: 用碳酸氢钠（NaHCO₃）溶液中和，再擦拭并用清水冲洗。碱液泄漏则用稀醋酸或硼酸溶液处理。

Mercury Spills (汞泄漏): Sprinkle sulfur powder to form mercury(II) sulfide, which reduces vaporisation and can be safely collected. Never pour mercury down the sink.

汞泄漏（Mercury Spills）: 撒硫粉使汞转化为硫化汞（HgS），降低蒸发并便于安全收集。切勿将汞倒入水槽。

9. Cleaning and Maintenance of Apparatus | 仪器清洗与维护

Proper cleaning prevents cross-contamination and ensures reproducible results. The cleaning method depends on the nature of the residue.

正确的清洗方法可防止交叉污染并保证结果的可重复性。清洗方式取决于残留物的性质。

Water-Soluble Residues (水溶性残留): Rinse thoroughly with tap water, followed by three portions of distilled water. The final rinse should drain evenly without forming droplets on the glass surface.

水溶性残留: 先用自来水充分冲洗，再用蒸馏水涮洗三次。最后一次涮洗后水应均匀流下，不在玻璃表面形成水珠。

Oil/Grease Residues (油污残留): Wash with a detergent solution or a small amount of organic solvent such as acetone, then rinse thoroughly. Chromic acid cleaning mixture is highly effective but extremely hazardous and is now rarely used.

油污残留: 用洗涤剂溶液或少量有机溶剂（如丙酮）清洗，然后彻底冲洗。铬酸洗液效果强但危险性极高，现已很少使用。

Calcium Carbonate / Alkaline Residues (碳酸钙/碱性残留): Dissolve in dilute hydrochloric acid, then rinse with distilled water.

碳酸钙/碱性残留: 用稀盐酸溶解后，再用蒸馏水冲洗。

After cleaning, dry the apparatus appropriately: air-dry inverted on a rack, or dry in an oven for glassware. Never wipe dry with cloth as this introduces fibres.

清洗后应正确干燥：倒置在架上自然晾干，或用烘箱干燥玻璃器皿。切勿用布擦拭，以免引入纤维。

10. Common Errors in Practical Exams | 实验考试常见错误

Recognising frequent pitfalls helps you avoid them. Examiners design questions specifically to test awareness of these errors.

识别常见陷阱有助于规避错误。考官设计的题目专门考查对这些错误的认识。

Reading the meniscus incorrectly (弯月面读数错误): Always read at eye level from the bottom of the meniscus. Viewing from above or below causes parallax error. 必须平视弯月面底部。从上方或下方读数会产生视差误差。
Not rinsing apparatus properly (仪器润洗不当): Failing to rinse the burette or pipette with the solution to be used dilutes the reagent. 未用待取液润洗滴定管或移液管会稀释试剂。
Overheating volatile liquids (过度加热挥发性液体): Always use a water bath when heating flammable or volatile substances to prevent ignition. 加热易燃或挥发性物质时务必使用水浴以防着火。
Using a measuring cylinder for titration (用量筒做滴定): This provides insufficient precision; use a burette or pipette. 量筒精度不足，滴定必须使用滴定管或移液管。
Forgetting to remove the funnel before adjusting the volume in a volumetric flask (容量瓶定容前未取出漏斗): The funnel’s contents add extra volume when removed. 漏斗中的液体会在取出时额外加入，导致体积偏差。

11. Exam Strategy: What to Memorise | 应试策略：必须记忆的内容

For maximum marks in practical questions, focus your revision on the following high-yield facts.

要在实验题中拿到高分，复习时应聚焦以下高价值考点。

Instrument precision table (仪器精度表):

Flow of readings (读数记录流程): Always record to the appropriate precision – two decimal places for burette and pipette volumes; do not add extra zeros beyond the instrument’s capacity.

读数记录流程: 始终按照仪器精度记录——滴定管和移液管记录两位小数；不要超出仪器精度随意添加零位。

Sequence of assembling a reflux apparatus (回流装置安装顺序): On the retort stand from bottom to top: tripod → heating source → round-bottom flask → condenser → receiving flask.

回流装置安装顺序: 铁架台上从下至上：三脚架 → 热源 → 圆底烧瓶 → 冷凝管 → 接收瓶。

Practise drawing and labelling each apparatus in an exam-style diagram. Many boards award marks for correct, labelled diagrams of experimental setups.

练习绘制并标注每种仪器的考试风格示意图。许多考试局会因正确标注实验装置图而给分。

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Chemistry Experiment Exam Points: Common Instruments & Basic Operations | 化学实验考点：常用仪器与基本操作