high school chemistry lab accident stories

One common cause is lack of attention. Students might be chatting with friends or thinking about other things and not focusing on what they are doing in the lab.

I heard of an accident where a student was distracted while pouring a concentrated acid. He poured too much and it started to fume vigorously. The fumes were irritating and made it difficult to breathe in the lab for a while. Teachers quickly evacuated the students and ventilated the area properly. This incident emphasizes the need for full concentration during lab work.

This combination of subjects had a certain advantage. In terms of learning difficulty, compared to some traditional science combinations, the learning pressure was relatively small. Chemistry and biology were closely related, and they could promote mutual understanding in the learning process. They might also have an advantage in terms of grading. From the perspective of the available majors, because there was no physics, it would limit the application of some science majors. The proportion of available majors was not very high, but there were still more choices. The subject of geography had the characteristics of both liberal arts and science. For this combination, it could increase the advantages of liberal arts. If the student was interested in chemistry and biology, had a certain learning ability in geography, and did not plan to apply for a major with high physics requirements, this combination was a good choice. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>

The common reaction devices in middle school chemistry included the following: 1. ** Test tube reaction device **: - Can be used at room temperature or under heating conditions. It could be used as a reaction vessel for a small amount of reagents at room temperature or when heated. It could also be used to dissolve a small amount of solid and collect a small amount of gas. It could also be used as a small gas generator. When heating, the outer wall must be dry. It cannot be suddenly heated and cooled. Generally, it must be evenly heated first before it can be concentrated. When heating solid, the mouth of the test tube should be slightly inclined downward, and the test tube cannot stand upright before it is cold. When heating liquid, the amount of liquid should generally not exceed 1/3 of the volume of the test tube, so that the test tube and the table form an angle of about 45°. The liquid in the test tube during the reaction should not exceed 1/2 of the volume of the test tube. The test tube clip should be clamped in the upper middle of the test tube (or the iron clip should be clamped 1/3 away from the test tube mouth). 2. ** Beaker reaction device **: - It could be used to dissolve solid substances, formulate solutions, dilute and concentrate solutions, and could also be used for reactions between large amounts of substances. When heated, the outer wall should be dry, and placed on the gauze to make it evenly heated. The amount of liquid added should generally not exceed 1/2 of the volume. 3. ** Flask reaction device **: - There were round-bottom flasks and flat-bottom flasks. Round-bottom flasks were generally used as reaction vessels under heating conditions. They could be used for reactions between large amounts of liquids, and could also be used as gas generators. The bottom of the round-bottom flask was relatively uniform in thickness and had no edges. It could be used for long-term strong heat. When heating, it should be placed on an earthworm net and could not be heated directly with a flame. Flat-bottomed flasks were used for gas generators without heating, and were also commonly used to assemble washing bottles. Due to the small bottom plane, the edges were sharp, and the stress was large, it was easy to explode when heated, so it was generally not used for reaction vessels under heating conditions. 4. ** Conical Flask Reaction Device **: - It is commonly used in reactions involving liquids and can be used to assemble gas generators. Usually, it needed to be indirectly heated with a cushion of gauze to make the heat uniform and prevent the instrument from cracking due to uneven heating. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>

There were many situations in the fluorescent reaction in junior high school chemistry. Some of the simple compounds that contain either the Lanthanide series or the Actinide series emit fluorescence under violet light. For example, in some experiments, mixing the chemicals in the red glow stick together and adding a solution of soda could produce beautiful red fluorescent droplets. There was also the fluorescent experiment of the fluorescent substance, which was to first add the solution of the fluorescent substance into the water, then add the fluorescent substance into the solution after dissolving it. Under the illumination of a purple light, the prepared solution would produce a fluorescent phenomenon when dripped into the water. The rare earth luminous powder kirakira on the market also had fluorescent properties. There were also common fluorescent materials that were lit up with blood or iron. Adding other fluorescent dye could also get different colors of fluorescence. Bis-esh-esh fluorescent ester could be used as a light stick. With the addition of different fluorescent dye, all colors of fluorescence and even infrared light could be obtained. In addition, many chemicals would produce fluorescence under different reaction conditions or combinations. For example, the luminol light reaction could be used to replicate the blue light effect of the " blue tears." In the experiment of the nitrogen fountain, the mixture of the luminol solution and the disinfectant solution could also emit blue light. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>

High School Mathematics, Physics, Chemistry, Biology, Formula Theorems, and Required Knowledge Complete Solution to the Key Points of High School College Entrance Examination Knowledge General Review (Jiangxi People's Press) could be used as review materials for high school mathematics, physics, and chemistry students. In addition,"King of Problem Solvers" was also a mathematics, physics, and chemistry study reference book suitable for Grade One, Grade Two, and Grade Three students. It was universal across the country. It contained three sections: "Top Student teaches you the outline,""Top Student teaches you how to solve problems," and "Top Student helps you avoid mistakes." Buying mathematics, physics, and chemistry subjects could also obtain a breakup book and video tutorial. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>

You might expect colorful chemicals, fun experiments, and maybe some wacky inventions.

The reaction types in high school students 'organic chemistry included substitution reactions, addition reactions, and so on. A substitution reaction is a reaction in which certain atoms or atomic groups in an organic compound are replaced by other atoms or atomic groups. In middle school chemistry, substitution reactions included specific types such as substitution, fermentation, dehydration, nitration, and substitution. For example, alkyls, alkyls, aromatic compounds, alcohol, and acids can undergo substitution reactions with the simple substances of the halo. The nitration reactions of the aromatic compounds, alcohol, and alkyls can be carried out. Almost all of the aromatic compounds and their compounds can be Sulfonated. Carboxylic acid and alcohol can undergo ester reactions. Halocarbon, ester, glycan, disose, and protein can undergo a cleavage reaction under certain conditions. The reactions of alcohol, alcohol, and carbolic acid with active metals such as Na (also a substitution reaction) can be carried out. The reactions of alcohol and hydrogen Halide (HX) can be carried out. Carboxic acid or alcohol can undergo intermolecular dehydration reactions. An addition reaction is a reaction in which the saturated carbon atoms in an organic compound directly combine with other atoms or atomic groups to form a compound. In middle school chemistry, compounds with double bonds or triple bonds in their molecular structure could undergo addition reactions, such as alkene, diene, alkyne, and its homolog. Aldol, keton, and higher fatty acid, as well as their glycers and monosomes. Usually, the organic reagents involved in the addition reaction include small molecules such as H <2>, X <2>(X is Cl2, Br2, I), HX, H <2> O, and HCN (symmetrical or unsymmetrical reagents). However, it was important to note that the carbon-oxygen double bond in the ester group and the ester group could not undergo an addition reaction. In addition, except for carbon dioxide, which did not contain hydrogen, most organic substances could undergo an oxidoreduction reaction (because they could be burned). <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>

In the new college entrance examination in Yunnan, chemistry, biology and other four re-elected subjects such as ideology and politics, chemistry, geography, and biology were included in the total admission score of ordinary colleges and universities, while Chinese, mathematics, foreign languages, physics, and history were based on original scores. The grading method for the grade conversion was as follows: First, the examinees were divided into grades according to their original scores. Grade A accounted for 15% of the examinees, and the score range was 100 - 86 points; Grade B accounted for 35% of the examinees, and the score range was 85 - 71 points; Grade C accounted for 35% of the examinees, and the score range was 70 - 56 points; Grade D accounted for 13% of the examinees, and the score range was 55 - 41 points; Level E accounted for 2% of the population, and the score range was 40 - 30 points. Then, according to the grading formula (y2 - y)/(y-y1)=(x2 - x)/(x-x1), the examinee's original score would be converted into the corresponding grade score (When the college entrance examination results were inquired, the examinee would get the converted score, so there was no need for the examinee to calculate it himself). <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>