It can only be extracted from the deep mountains after being struck by thousands of hammers. It regards the burning of the burning fire as a very common thing.
Don't be afraid of being smashed to pieces, leaving innocence in the world.
Students! Have you read this poem? If so, do you know the chemical knowledge contained in it? Maybe you know, maybe you don't know. It doesn't matter, you will understand after reading the following!
First, open the door to chemistry.
The world around us is a material world. These substances are changing all the time: huge rocks are gradually weathering into mud and gravel; Ancient trees buried deep underground due to crustal changes have become coal; Iron gradually rusts in humid air; Wait a minute.
In order to live and produce, human beings have accumulated a lot of knowledge about material changes in the process of long-term struggle with nature. Gradually realize that all material changes in nature have certain reasons and conditions. Mastering the causes and conditions of material changes can further control the occurrence of material changes, thus achieving the purpose of utilizing and transforming nature.
Chemistry is a basic natural discipline that studies the properties and changing laws of matter. It studies the causes and conditions of material changes and various phenomena (such as luminescence, heat release, gas production, etc.). ) happens with change.
Second, enter the door of chemistry
The development of socialist modernization in China is closely related to the growth of energy consumption. Traditional energy sources are mainly fossil fuels, such as coal, oil and natural gas. In order to improve the effective utilization of these energy sources, chemical knowledge and the efforts of chemists are indispensable in the innovation of these technologies. Chemistry also plays a great role in the development of new energy.
The advantages of nuclear energy and solar power generation devices are inseparable from the development of special materials.
1. Practical new energy-battery
A new type of battery with aluminum-air-seawater as energy source is the first in China, which can be used as a water marker lamp and has been successfully developed. also
Special batteries, such as solar cells, are devices that use crystalline silicon and amorphous silicon as materials to convert solar energy into electrical energy. This kind of battery has the broadest prospect because it has no pollution. It is predicted that by the middle of 2 1 century, 20%~30% of the global total electricity consumption will be provided by solar cells. Hydrogen-oxygen combustion battery is a new type of battery with high efficiency and low pollution, which is mainly used in aerospace field. The electrode materials are generally activated electrodes with strong catalytic activity, such as platinum electrode and activated carbon electrode, and the electrolyte solution is generally 40% KOH solution. The electrode reaction is as follows: H2 = = = 2H2H+2OH? 0? 4—2e=2H2O
Positive electrode: O2+2h2o+4e = = = 4oh? 0? four
Total battery reaction: 2h2+O2 2h2o.
The reason why the electronic watch can walk around day and night, the liquid crystal display of the pocket electronic computer displays numbers and so on depends on the miniature battery. The electronic watch uses a silver-zinc battery, and the chemical reaction equation is: Ag2O+2Zn = = = = Ag+2ZnO. Silver-zinc batteries can be used in electronic watches for up to two years. 1958 the first pacemaker was successfully implanted in Sweden, and its service life was as long as 10 years. Lithium iodine battery has the longest installation life and the highest reliability. How amazing!
2. Future energy-taking fire from water
At present, all countries in the world are exploring new energy sources, such as solar energy, tidal energy, geothermal energy, hydrogen fuel and nuclear energy, among which hydrogen is the most promising new fuel, and hydrogen comes from inexhaustible water. H2O = = = H2+O2 =, seawater can be directly converted into hydrogen by photochemical method, biological method or solar energy. Once water really becomes the raw material for hydrogen production, mankind will get lasting energy. With the development of science and technology, the extractable water will become a kind of cheap energy widely used by human beings. Cars, ships, planes and all kinds of power equipment will use hydrogen as fuel. More significantly, hydrogen fuel reacts with oxygen to synthesize water, which is endless, making hydrogen an inexhaustible energy source for human beings.
The door of chemistry is open everywhere.
1. Clothes With the improvement of living standards, people like to wear sweaters and wool coats. As the saying goes, "wool is on sheep", but there is no "wool" on sheep. This is a large number of acrylic wool filled in the wool counter of department store. Acrylic fiber is called "synthetic wool", the scientific name is polyacrylonitrile, which has the characteristics of wool and is superior to wool at first. How is acrylic fiber synthesized? The raw material for making acrylic fiber is acrylonitrile (CH2===CHCN), which can be made of calcium carbide or propylene in the waste gas from petroleum cracking and refining. After ammonia oxidation, propylene becomes acrylonitrile;
CH2 = = = = CH-CH3+NH3+3/2O2 ammonium phosphomolybdate
400~500 degrees Celsius
CH2====CH—CN +3H2O
Acrylonitrile is converted into polyacrylonitrile by polymerization, and then acrylic fiber is formed by spinning and spinning.
When eating fried dough sticks, soda ash and alum are often added to the dough. Why? In fact, the inventor of fried dough sticks
Man may not know chemistry, but he unconsciously applied three chemical principles and got the popular fried dough sticks. Soda soda (NaHCO3) and sodium hydroxide (NaOH), which is the first reaction to make fried dough sticks:
Sodium carbonate+H2O = = = sodium bicarbonate+sodium hydroxide. The second reaction is that the generated sodium bicarbonate is decomposed into sodium carbonate, water and carbon dioxide by heating: 2NahCO3 = = = = Na2CO3+H2O+CO2 ↑. In this way, many tiny air chambers filled with carbon dioxide are formed in the dough, and the gas will expand when heated, so the fried dough sticks will expand rapidly when fried. But the above two reactions will produce more sodium hydroxide, because sodium hydroxide is a strong alkali and cannot be eaten. The inventor of fried dough sticks knew to neutralize the alkalinity of sodium hydroxide with alum. The aluminum hydroxide produced by the reaction exists in the form of colloid, which is beneficial to wrap carbon dioxide gas and make the dough more malleable. Aluminum hydroxide is the main component of weishuping, which can neutralize excessive gastric acid (hydrochloric acid) produced in the stomach and protect the gastric mucosa. Therefore, it is good for people with stomach problems to eat fried dough sticks often. Not only has high nutritional value, but also can make your stomach comfortable.
Living in polyvinyl chloride (PVC), do you know its function? It is the chemical raw material of wallpaper, which is a kind of wall decoration material widely used in home. Evenly coated on the backing paper with a scraper, and printed and embossed at the bottom of the ditch after a certain process. The soap boxes, combs, slippers, sandals, sheets and buckets we use are all made of PVC, some of which are softer than silk and some are harder than steel. In the production of these materials, different quantities and qualities of additives are added to make plastic products meet people's expected requirements.
All right, we're done here. Ask students to think about the chemical knowledge contained in Yu Qian's poems. Read it a hundred times to see what it means! Some of the above are common in daily life, very few. If you want to know more about chemistry, you should see, listen and feel in your life.