I. Containers and reactors
1. can be directly heated.
(1) test tube
Main uses:
① Used as a reaction container for a small amount of reagents under normal temperature or heating conditions.
② Collect a small amount of gas and check its purity.
Usage and precautions:
(1) can be directly heated and taken out from the test tube mouth 1/3 with a test tube clamp.
② There are large and small test tube specifications. The liquid in the test tube does not exceed the volume of 1/3.
(3) There should be no water drops on the outer wall before heating; Do not quench after heating to prevent the test tube from breaking.
(4) When heating, the nozzle should not be directed at anyone. When heating solids, the test tube should be placed horizontally with the nozzle slightly inclined downward.
⑤ Do not use a test tube to heat and melt strongly alkaline substances such as NaOH.
(2) evaporating dish
Main uses:
① Evaporation, concentration and crystallization of the solution.
(2) dry solid matter.
Usage and precautions:
① The liquid capacity shall not exceed 2/3 of the volume.
② It can be directly heated, but it cannot be quenched after heating.
(3) Take and put the evaporating dish with crucible tongs.
2. The asbestos pad can be heated.
(1) beaker
Main uses:
① Used as a container for dissolving solid matter and diluent.
② Used as a container for a large number of reagent reactions.
③ A cold-dry beaker can be used to test whether water is generated during gas combustion; Beakers coated with lime water can be used to test CO2 gas.
Usage and precautions:
① The commonly used specifications are 50mL, 100mL, 250mL, etc. , but the liquid is measured without a beaker;
(2) It should be heated on the asbestos net to make it heated evenly; When heating, there should be no water droplets on the outer wall of the beaker.
(3) When heating the liquid, it should generally not exceed 1/2 of the beaker volume.
(4) In the process of dissolution or dilution, when stirring with a glass rod, do not touch the bottom or wall of the cup.
(2) flask
Main uses:
① It can be used as a reaction container with a large amount of reagents and liquids, and is often used in various gas generating devices. ② Distillation bottles are used to separate mutually soluble liquids with different boiling points.
Usage and precautions:
(1) should be heated on asbestos net to make it heated evenly;
When heating, there should be no water drops on the outer wall of the flask;
② Flat-bottomed flask cannot be used for heating for a long time;
(3) conical flask
Main uses: it can replace gas production reactors such as test tubes and flasks.
Usage and precautions: when heating, you need to pad asbestos mesh.
3. Can't heat
(1) gas container (frosted edge of bottle mouth)
Main uses:
(1) It can be used with ground glass sheets to collect and temporarily store gas.
② Used as a reaction container for the reaction between substances and gases.
Usage and precautions:
(1) cannot be heated.
(2) The gas with density greater than air should temporarily put the bottle mouth upward.
③ When carrying out combustion experiments, it is sometimes necessary to put a small amount of water or fine sand at the bottom of the bottle.
(2) Wide-mouth bottles and narrow-mouth bottles (frosted inside the bottleneck)
Main uses:
① jar is used to store solid drugs, and can also be used to assemble gas generators (without heating).
② The flask is used to store liquid medicine.
Usage and precautions:
(1) generally cannot be heated.
(2) acidic drugs, oxidizing drugs, and organic solvents should use glass plugs; Rubber plugs should be used for alkaline reagents. (3) Look at the light with a brown bottle and it will deteriorate easily.
(3) Dropping bottle
Main uses: for storing a small amount of liquid, characterized by convenient use.
Usage and precautions:
① The dropper should not be placed flat or upside down to prevent liquid from flowing into the rubber head.
② When holding alkaline solution, use cork or rubber stopper.
③ Alkaline reagents cannot be stored for a long time.
Two. measuring instrument
(1) measuring cylinder
Main uses: roughly measure the volume of liquid (its accuracy can reach 0. 1mL).
Usage and precautions:
(1) The larger the specification of the measuring cylinder, the lower the accuracy.
② The measuring cylinder has no zero scale.
(3) When measuring liquid, the measuring cylinder must be flat, and the line of sight should be flush with the lowest concave surface of the liquid in the measuring cylinder.
(2) Pallet balance
Main uses:
It is used to roughly weigh the mass of substances, and its accuracy can reach 0.1g.
Usage and precautions:
① Adjust the "0" point before weighing: move the code to zero and adjust the balance.
(2) When weighing, two boards are padded with paper, with left and right yards; The deliquescent and corrosive drugs must be weighed in glassware.
(3) After weighing: return the weight to the box and return the travel code to zero.
Three. Heating instrument
spirit lamp
Main uses:
Common heat sources in chemical laboratories.
Usage and precautions:
(1) The alcohol content shall not exceed 2/3 of the volume and shall not be less than1/2 of the volume;
It is absolutely forbidden to add alcohol to the burning alcohol lamp to avoid fire;
(3) When the lamp holder is extinguished, it cannot be blown out with the mouth;
(4) heating with external flame;
Four. Filter instrument
chimney
Main uses:
(1) universal funnel
(1) Inject liquid into a small mouth container;
② Used for filtering device;
(3) device for preventing back suction;
(2) Long-necked funnel:
(1) inject the liquid into the reactor;
② Assemble the gas generating device.
Usage and precautions:
(1) cannot be directly heated by fire;
② The lower end of the long-necked funnel should be inserted below the liquid level;
5. Other commonly used chemical instruments
1. cylinder cleaning
Main uses: used for washing gas and removing moisture or other gas impurities.
Usage and precautions: Pay attention to the flow direction of gas when using, which is generally "long in and short out". The volume of liquid in the bottle should be 1/3, and it should not exceed 2/3.
2. glass rod
Main uses: It is often used for mixing and drainage.
Usage and precautions: avoid touching the wall when mixing.
Attachment: Content and format of experimental report
Writing an experimental report is an important basic training. It is not only the summary of each experiment, but more importantly, it can initially cultivate and train students' logical induction ability, comprehensive analysis ability and writing expression ability, which is the basis of scientific and technological paper writing. Therefore, every student who takes part in the experiment should write the experiment report in time and seriously.
The content is realistic, the analysis is comprehensive and concrete, the text is concise and smooth, and the copying is clear and tidy.
(a) the name of the experiment
The content of the experiment should be reflected in the most concise language. If a program, law or algorithm is verified, it can be written as "Verification?" ; Analysis? .
(2) Course name
(three) the name of the student, student number, partner.
(4) Date and place of the experiment (year, month, day)
(5) experimental purpose
Objective To verify theorems, formulas and algorithms clearly in theory, so that experimenters can gain a profound and systematic understanding, and master the skills and skills of using experimental equipment and the debugging methods of programs in practice.
Generally, it is necessary to explain whether it is a verification experiment or a design experiment, an innovative experiment or a comprehensive experiment.
(6) experimental principle
The main principles related to the experiment are described here.
(7) experimental contents
This is an extremely important content in the experimental report. To grasp the key points, we can consider it from both theory and practice. This part should specifically explain the principle, law algorithm or operation method on which the experiment is based.
Detailed theoretical calculation process. (8) Experimental environment and equipment.
(9) Experimental steps
Write only the main operation steps, don't copy the internship instructions, be concise. You should also draw the flow chart of the experiment (schematic diagram of the structure of the experimental device) with corresponding text descriptions, which can not only save a lot of text descriptions, but also make the experimental report concise and clear.
(X) Experimental results
Description of experimental phenomena, processing of experimental data, etc. The original data should be attached to the experimental report of the main operator of this experiment, and the author of the same combination should copy the original data. There are usually three ways to express the experimental results:
1. Text description: Systematize the original data according to the purpose of the experiment, objectively describe the experimental phenomena and results in accurate technical terms, with time sequence and the relationship between indicators.
2. Chart: tables or coordinate charts are used to make the experimental results prominent and clear, which is convenient for comparison, especially suitable for multiple groups of experiments with consistent observation indexes, so that the similarities and differences between groups can be seen at a glance. Each chart should have a list and a unit of measurement, and it should explain some central issues.
3. In the experimental report chart, you can choose one or more methods to get the best results.
(1 1) discussion
According to the relevant theoretical knowledge, the experimental results are explained and analyzed. If the experimental results are consistent with the expected results, what theory can it verify? What is the significance of the experimental results? What's the problem? These are the experimental reports that should be discussed.
However, we can't apply the known theory or life experience to the experimental results. Moreover, we can't choose or even modify the experimental results just because they don't conform to the expected results or theories. At this time, it is necessary to analyze the possible reasons for its abnormality. If this experiment fails, it is necessary to find out the reasons for the failure and the matters needing attention in future experiments. Don't simply repeat the theory in the textbook and lack the content of your own active thinking.
In addition, you can also write some experiences of this experiment and put forward some questions or suggestions.
(12) conclusion
The conclusion is not a repetition of the specific experimental results, nor a prospect of future research, but a concise summary of the concepts, principles or theories that can be verified in this experiment. It is a general and general judgment summed up from the experimental results, which should be concise, accurate, rigorous and objective.