This article describes the critical role of volumetric flasks in chemical laboratories, especially in the preparation of standard solutions and in improving the accuracy of titration analysis. The accurate measurement function of the volumetric flask makes it an indispensable tool in the experiment, ensuring the reliability of the experimental results. Through an in-depth discussion of the specifications and operation skills of volumetric flasks, this paper aims to help experimenters optimize the experimental process and improve the accuracy and consistency of experimental data.
1. The basic operation of titration analysis
1. Burette washing, grease, leak detection, liquid filling and operation
Overview of burettes
Type and use: acid type is used for acid solution, alkaline type is used for alkali solution, and other types are used for special solution
Washing of burettes
Cleaning steps: Rinse with tap water, then thoroughly clean with chromium pickling solution, and then rinse with distilled water
Special precautions: Avoid direct contact between the rubber tube and the cleaning agent to prevent corrosion
Greasing and leak detection of burettes
Grease method: Apply petroleum jelly to the piston and nozzle to avoid leakage of the solution
Leak detection steps: Check the piston and tube tip for leakage to ensure that the seal is good
Burette filling and handling
Filling step: Wash the burette with the desired solution, then fill with liquid and exclude air bubbles
Titration operation tips: keep the solution flow rate uniform, avoid air bubbles affecting the reading, and read the scale accurately
2. Preparation and operation of volumetric flasks
Overview of volumetric flasks
Type & Use: Choose a volumetric flask of the appropriate size to meet the experimental requirements
Preparation of volumetric flasks
Inspection steps: Make sure the volumetric flask is accurately scaled, check the influence of photosensitizing substances before use, and clean the glass grinding plug
Use of volumetric flasks
Solution preparation: accurately measure the liquid to the scale mark to avoid excessive or insufficient to ensure the accuracy of the operation process
Second, the operation of the pipette
Basic operation of pipettes
Washing and wetting
Washing steps: Wash gradually with tap water, dilute acid or lye, distilled water to remove residues
Wetting method: Wet the inner wall of the pipette with the liquid to be transferred to ensure accurate measurement
Liquid Transfer: Technical Essentials and Frequently Asked Questions
Technical points: Make sure the liquid is at the tick mark, avoid air bubbles, and use an even suction and drain action
Common Problem: Handle accurate readings of air bubbles, liquid residues, and tick marks to ensure accurate operation
3. Laboratory safety and maintenance
The instrument is safe to use
Precautions for handling chemicals: Wear appropriate personal protective equipment, avoid direct contact and inhalation of chemicals, and be familiar with the nature of chemicals and how to handle them.
Common safety practices in the laboratory: follow the operating procedures, keep the laboratory well ventilated, receive regular safety training, and understand emergency handling measures.
Instrument maintenance and maintenance
Regular Inspection and Cleaning: Regularly check the function and performance of the instrument, clean and calibrate it in a timely manner, and avoid using expired or damaged instruments.
Precautions for long-term storage and storage: Store the instrument according to the manufacturer's recommendations, avoid extreme temperature, humidity and strong light, and perform regular maintenance and inspection.
Fourth, summary
The basic operation techniques of the chemical laboratory mainly cover the basic operation of titration analysis and the preparation and use of volumetric flasks. Proper handling of burettes, volumetric flasks, and pipettes is key to ensuring experimental accuracy in titration analysis. The use of burettes involves washing, grease, leak detection and liquid filling, and it is necessary to pay attention to the type of burette and the corresponding requirements for use, such as the difference between acid and basic burettes. The technical details of the titration process, such as how to control the flow rate of the titrant, how to read the liquid level accurately, and how to avoid errors, all have a direct impact on the reliability and accuracy of the experimental results.
The use of volumetric flasks focuses on the preparation of solutions of the exact concentration. Volumetric flasks need to be checked for size, tightness, and suitability for the preparation of specific types of solutions. In conclusion, mastering these basic techniques can effectively improve the accuracy and reliability of experiments, and are indispensable skills in chemistry laboratories.
