195 What are the commonly used heating equipment in laboratories?

What are the commonly used heating equipment in the laboratory The commonly used heating equipment in the laboratory is electric furnace, high-temperature furnace, electric constant temperature drying box, electric hot plate, sand bath, electric constant temperature water bath, etc. Precautions for using the electric furnace: (1) The voltage of the power supply should be consistent with the voltage specified by the electric furnace itself.

2) The continuous use time of the electric furnace should not be too long, too long will shorten the life of the electric furnace. (3) If the heated container is metal, do not touch the electric furnace wire, so as to avoid electric shock accidents or short circuits and burn the furnace wire. (4) The groove of the refractory furnace should be kept clean, and the burnt debris should be removed in time to protect the furnace wire with good heat transfer and prolong the service life.

Instruments that can be heated directly: test tubes, evaporation dishes.

Crucibles, incendiary spoons.

Indirectly heated (with asbestos netting): Beaker.

Flasks, Erlenmeyer flasks.

Instruments that cannot be heated: graduated cylinders.

Gas collectors, funnels, thermometers.

Dropper bottles, surface dishes, jars, bottles, etc.

The instruments used in specific experiments in natural sciences are mainly used in physics, chemistry and biology (including chemical instruments). Modern commonly used experimental instruments include test tubes, beakers, evaporation dishes, crucibles, and alcohol lamps.

Brinell funnels, gas washing cylinders, drying tubes, tray balances, graduated cylinders, volumetric flasks.

Burettes, measuring devices, etc.

1. Crucible: It is an important part of chemical instruments, it is a container for melting and refining metal liquids and solid-liquid heating and reaction, and is the basis for ensuring the smooth progress of chemical reactions. It can be heated directly, and can not be quenched after heating, and can be removed with crucible pliers.

2. Evaporation dish: It is a vessel that can be used to evaporate concentrated solutions. It can be heated directly on a tripod, or indirectly with an asbestos net, water bath, etc., and when heated, it can be stirred with a glass rod.

3. Beaker: refers to a common laboratory glassware, made of glass, plastic, manuscript or heat-resistant glass. The beaker is cylindrical in shape and has a notch on one side of the top for easy pouring of liquids.

Beakers are widely used for heating, imitation bucket dissolution, mixing, boiling, melting, evaporation concentration, dilution, precipitation clarification of chemical reagents, etc.

4. Test tube: a commonly used instrument in the chemical laboratory, used as a reaction vessel for a small amount of reagents, at room temperature or when heated (it should be preheated before heating, otherwise the test tube is easy to burst.) ) use.

5. Flask: It is a necked glassware used in the laboratory to hold liquid substances. It is called a flask because it can withstand a certain amount of heat. Flasks are usually flat-bottomed and round-bottomed and usually have the appearance of a round-bellied thin neck.

Heating is as follows:Commonly used heat sources in laboratories are gas, alcohol, and electricity. In order to accelerate organic reactions, heating is often required, and there are direct heating and indirect heating in terms of heating methods.

In the organic laboratory, there is no need for direct heating, such as heating the round-bottom flask with an electric heating plate, which will lead to local overheating and even rupture due to uneven heating, so it is forbidden to directly heat flammable solvents with open flames in the laboratory safety rules.

Introduction:

A laboratory lab is a place where experiments are conducted. The laboratory is the cradle of science, the base of scientific research, the source of scientific and technological development, and plays a very important role in the development of science and technology.

Laboratories can be divided into three categories according to their ownership: the first type is laboratories that are affiliated with the university or managed by the university; The second category of laboratories belongs to state institutions.

Some are even international institutions.

The third type of laboratory is directly under the industrial enterprise sector and serves the development and research of industrial technologies.

In chemical experiments, chemical instruments that can be directly heated include test tubes, evaporation dishes, crucibles, and burning spoons.

Preheat the tube before using it, wipe the outside of the tube dry when heating, and clamp the tube from the nozzle with a tube clamp. When heating the solid reagent, the bottom of the tube should be slightly higher than the nozzle to prevent the condensate from backing up and bursting the tube. After heating, it should continue to be fixed or placed on the asbestos net to allow it to cool naturally.

The evaporation dish should be picked and placed with crucible pliers, and fixed with a tripod or iron frame when heating. After heating, it should be placed on an asbestos net to avoid burning the laboratory table.

The crucible should be placed on the mud triangle when heated, stirred when evaporating, and steamed with waste heat when it is almost dry. After heating, it cannot be quenched, remove it with crucible pliers, and put it on the asbestos net.

The combustion spoon is used to hold flammable solid substances for combustion tests, especially the combustion reaction of substances in gases.

The instruments that can be directly heated in chemical experiments are: test tubes, evaporation dishes, and crucibles.

Incendiary spoon. Indirect heating is available (asbestos mesh or barbed wire mesh is required): beaker.

Flasks, Erlenmeyer flasks. Instruments that cannot be heated are: graduated cylinders, gas collection cylinders, funnels, and thermometers.

Drop bottles, surface dishes, jars, bottles, etc.

Direct heating is suitable for experiments where temperature is not required accurately and the temperature needs to rise quickly. Indirect heating is suitable for experiments that cannot be heated with an open flame or have high environmental requirements and cannot involve impurities.

Test tubes, burning spoons, evaporation dishes, and crucibles. The instruments that can be directly heated in the laboratory are: test tubes, burning spoons, evaporation dishes and crucibles; The asbestos nets that need to be padded are: beakers, flasks, Erlenmeyer flasks, etc.; Instruments that cannot be heated are: funnels, measuring cylinders, gas collection cylinders, etc.

Explosive and unstable substances. Such as concentrated hydrogen peroxide, organic peroxide, etc.

Oxidizing substances. Such as oxidizing acids, hydrogen peroxide also falls into this category.

Flammable substances. In addition to flammable gases, liquids, and solids, it also includes substances that produce combustibles in moisture. Such as alkali metal hydrides, calcium carbide and substances that spontaneously ignite in contact with air, such as white phosphorus, etc.

Toxic substances. Corrosive substances. Such as acid, alkali, etc.

Radioactive material.

Flammable and explosive reagents should be stored in an iron cabinet (wall thickness of more than 1mm), and the top of the cabinet has a vent. It is strictly forbidden to store flammable liquids in bottles larger than 20L in the laboratory. Do not put flammable and explosive drugs in the refrigerator (except explosion-proof refrigerators).

Two or more compounds that can produce violent reactions, burn, and release toxic gases after mixing or contacting each other are called incompatible compounds and cannot be mixed. Most of these compounds are strong oxidizing substances and reducing substances.

Corrosive reagents should be placed in plastic or enamel plates or barrels to prevent accidents caused by bottle breakage.

It is necessary to pay attention to the storage period of chemicals, and some reagents will gradually deteriorate during storage, and even form a hazard.

In chemical experiments, some instruments can be straight.

Du connected to heating, such as: test tubes, evaporation dishes, crucibles and burning spoons;

Some instruments cannot be directly heated, and asbestos nets must be paddled when heating, such as: beakers, flasks, Erlenmeyer flasks, etc.;

The most commonly used heating tool in laboratories is an alcohol lamp;

Therefore, the answer is: test tubes, evaporation dishes, crucibles;

beakers, flasks, Erlenmeyer flasks;

Alcohol lamps