Wang Lijun

Department of Chemical Engineering, Shijiazhuang Vocational and Technical College, Shijiazhuang, Hebei)

Environmental protection, the development and utilization of energy, the development of functional materials and the exploration of the mystery of life process are the most important issues in the world at present. Are closely related to chemistry. People's food, clothing, housing and transportation, all sectors of the national economy and all fields of cutting-edge science and technology are inseparable from chemistry.

Key words: polymer materials; Nanotechnology; Environmental pollution; Life science; information

Chemistry is a central science, which is related to all aspects of social development.

Demand is closely related, [! The popularization of chemistry education is the need of social development.

The need to improve the cultural quality of citizens,

! Chemistry and clothing, food, housing and transportation

Whether it is cotton, linen or silk made of cloth, or

It is woolen cloth, which is nothing more than cotton fiber and silk fiber.

Wool fiber, they are all natural polymer materials), "century.

After the 1980 s, the clothes people wear have undergone qualitative changes.

Synthetic polymer material polyester (polyester) began to be replaced by a large number.

Cotton, hemp, silk and wool textiles; Nylon products appear in large numbers; Acrylic fiber spinning

The output of artificial wool such as polyester, nylon and acrylic fiber has increased greatly.

Synthetic fibers are all made of oil, natural gas and coal.

Synthetic polymer materials are made of polyacrylonitrile.

Made of artificial wool by flocculation, sprayed with aluminum-titanium metal reflective film, vulgar

Known as "space cotton", it has higher warmth retention than duck down; Cotton cloth is in use.

Before, it should also be chemically treated and printed to make it feel good.

It should have certain elasticity and bright colors, and it should be filled with grain bags and rich vegetable baskets.

One of the keys is the production of chemical fertilizers and pesticides, and the processing and manufacturing are excellent.

Food with good taste is inseparable from various food additives, most of which are

Extract from natural products by chemical synthesis or chemical separation.

Cement, lime, paint and glass are used in modern buildings.

Plastics are all chemical products, which are used as means of transportation for various modern traffic workers.

Use, not only need gasoline and diesel as power, but also need all kinds of gasoline.

Additives, antifreeze and lubricating oil are all produced in the petrochemical industry.

In addition, people need drugs, detergents, beauty products and cosmetics.

And so on are also chemical substances, which shows that we live in the chemical world.

Material refers to the use of simple materials or some functions of compounds by human beings.

The preparation of chemicals used to make articles is inseparable.

The rational application of chemistry and materials is also inseparable from the status of chemistry and materials.

To have a variety of different properties, is determined by its composition structure, and research

Studying the composition and structure of matter is the main content of chemical research because

Therefore, chemistry is not only an important part of materials science, but also a material discipline.

One of the foundations of learning,

Today, with the rapid development of high technology and increasingly fierce competition, countries

Everyone wants to occupy a place in biology, information, space, energy, ocean and other technical fields.

In a place, the development of new technology is often related to materials, so new profiles

The development of material itself has become a high technology, which can be called new material.

Technology, this symbolic technology is material design and molecular design, that is, according to needs.

It is necessary to design new materials with specific functions, such as high purity silicon and germanium.

The appearance of conductor materials has produced transistors, integrated circuits and large-scale

Integrated circuits and VLSI bring computing.

Machine revolution), in the era of "Century #", there was a/*, which had multiple pairs.

Bond, can form more compounds,/* "the diameter of the molecule is! 0 1,

There is a ",(*0 1" cavity in the center of the ball, which can accommodate other atoms or ions.

And can form new substances,/* "in superconductivity, electrochemistry, nonlinearity.

Apply sexual optics and high-temperature lubrication,

One of the hot spots in materials science research is nano-materials, which is made up of

Blocks or films formed by the aggregation of nano-sized small particles.

Artificial solid material, which is a new structure different from crystalline and amorphous.

The new structural form has brought many new properties, such as the solubility of 23.

The key point is *' "4, but its melting point of nano-powder can be lower than!" "4. Another example is the emerging nano-porous carbon materials, which can be used as catalyst carriers.

Bulk is also an ideal electrode material for high-efficiency and high-energy batteries!

"chemistry and energy

Energy refers to natural resources that can provide energy! Modern major energy sources

The source is coal, oil and natural gas, and their reserves are extremely limited! because

Therefore, while actively looking for new energy sources, all countries strongly advocate energy conservation.

Sure！ Chemical energy is one of the important energy sources in 2 1 century, among which

%&The battery is called green battery, which will not pollute the environment!

But hydrogen can't be used as an electrode directly, and it must be fixed in one place.

On this kind of plate, hydrogen storage alloy is usually used! Hydrogen storage alloys can be mixed with hydrogen.

Metal hydride is formed, so that hydrogen can be fixed and converted after heating.

When the gas is released, its hydrogen storage density can be greater than that of the hydrogen bottle! Alloy group

Synthetic structure is the main factor that determines its hydrogen absorption! As far as energy conservation is concerned,

Chemistry plays an important role! For example, fuel emulsification, rational utilization of coal, etc.

) chemistry and information

Information technology is closely related to chemistry because of information.

It is inseparable from the carrier and the medium, but the composition and chemical state of the carrier and the medium.

Status has a great influence on information! Through chemical synthesis, it can be made.

Production of information materials with different properties, mainly including electronic materials and optoelectronics.

Materials! There are many kinds of these materials, including metal and non-gold.

Genus, simple substances and compounds include most of the elements in the periodic table.

Sue! If superconductor is used in radar, its sensitivity can be greatly improved.

Effective range increased "! ) times! Optical messenger information communication can reach.

It has reached a new level, and optical communication cannot be separated from optical fiber! some

The role of materials in information technology is multifaceted! Such as semiconductors

Materials, which are not only the basic components of large-scale integrated circuits, but also

It plays a key role in information transmission, processing, storage and display technology.

Use!

:: Chemistry and environment

The development of chemical industry has also brought environmental pollution. now

The rapid development of green chemistry is to fundamentally solve this problem.

Question! Although chemistry has brought pollution, it is inseparable from civilization to control pollution.

Study! For example, in the early #+century, the refrigerant in the refrigerator was% (",-# and.

. "(/wait! But% ("toxic,-# toxic and corrosive, propane.

Easy to refuel! Therefore, we hope to find a non-toxic, tasteless, non-corrosive,

Easy to liquefy cheap refrigerant! To this end, people began to turn to

Periodic table of elements! American engineer Xiaomi deli according to the periodic table of elements

Freon refrigerant is synthesized and widely used in refrigeration equipment! then

Found that freon can destroy the ozone layer, and began to study fluorine-free refrigerators.

This all needs to start from understanding the nature of the reaction, and it is also inseparable from chemistry!

0 chemistry and life

Biological system is based on living matter, and life process is fundamental.

The body is a comprehensive expression of countless chemical changes! A living organism must

There must be information storage and transmission, reproduction, internal adjustment and external adaptation.

We should use the material and energy of the environment reasonably and effectively! from

At the molecular level, these functions are just one of many bioactive molecules.

The performance of organized chemical reaction between! In these reactions, one

The product of the reaction becomes the starting point of another reaction! Life is a series.

A dynamic chemical process that occurs inside and outside cells and is controlled by the whole organism.

Cheng, when these processes stop, life stops. no

The chemical reaction is over, but the decomposition and degradation of organisms have changed.

The beginning of another inorganic formation process! In graduate school, objects are things.

In the field of qualitative basis and basic laws of life activities, chemistry not only mentions

For methods and materials, we should also provide theories, viewpoints and technologies.

Play an important role!

References:

[1] Tang Youqi, Wang Kui! Chemistry and society [1]! Beijing: Higher Education Press, 223! We have studied chemistry, and we all feel that our knowledge has increased a lot. Chemistry is closely related to our life. Chemistry is everywhere in our life. As long as you pay attention, you can use the chemical knowledge you have learned to solve many small problems around you.

Next, let's solve a few problems that you often encounter.

Why do raw persimmons have astringency?

No matter who was born in the north or the south, people will have such a life experience: persimmons that are red as fire on persimmon trees are still inedible. At first taste, it is still very astringent. Is this persimmon not fully ripe? Yes, but if persimmons are fully ripe, it is not good for people to pick, transport and store them. Therefore, people often pick the persimmon when it turns red, and put it for a while, and it becomes a sweet and fragrant persimmon.

So, why does persimmon have astringency?

It turns out that this is because raw persimmons contain tannin (also called tannic acid), which makes persimmons astringent.

In order to get rid of the astringency of raw persimmons, people have come up with many ways in their constant life practice. Some people cover persimmons layer by layer with straw or pine needles, or bury persimmons in leaves with pears. After a period of time, the astringency of persimmons is gone. Some people directly scald persimmons with hot water, and the astringency of persimmons is naturally removed. Now people have adopted the "carbon dioxide deastringency method", which is actually a summary of people's past life experience. People seal persimmons in a room to increase the indoor carbon dioxide concentration and reduce the oxygen concentration. In this way, persimmons can't breathe normally, but breathe in the absence of oxygen. In the case of anoxic breathing, organic substances such as acetaldehyde and acetone will be produced inside raw persimmon. These organic substances can turn water-soluble tannins into water-insoluble substances, so persimmons are no longer astringent, but sweet.

If you also have a few raw persimmons that want to "get rid of astringency", you can put them in plastic bags and tie them tightly. Generally, the astringency can be removed in a few days.

How did the golden banana come from?

Students in the far north can also eat delicious, fragrant and sweet bananas in the south. Do you know why?

As we all know, bananas are a special product of the south. Born delicate, untouchable. If it is not done well, it will rot in batches, and raw bananas will not mature automatically. What can we do?

Don't worry. First of all, bananas are easy to damage and rot when they are ripe. Therefore, in order to transport bananas from far away southern Xinjiang, people can't wait until bananas are ripe, but harvest them when they are not ripe. At this time, the banana skin is green, and a lot of starch in the body has not been converted into glucose and fructose, so the "body plate" is very tough and doesn't care if it collides. This kind of banana is convenient for long-distance transportation.

The bananas delivered to the destination are still green skin and hard meat, and the taste is both astringent and not sweet. Of course, they cannot be sold in the market. Not when it's mature. Of course, people will find a way. The banana has been picked from the tree, and it has lost its ability to mature itself.

So, people found a way. They pumped gaseous ethylene (C2H4) into the warehouse where bananas were stored, which enhanced the activity of oxidoreductase in bananas and solidified water-soluble tannins. At the same time, chlorophyll in the peel disappeared, and blue-green bananas became popular in Huang Chengcheng. The pulp also becomes soft and gives off a fragrant smell. Bananas are ripe!

Ethylene can not only make bananas and other fruits mature, but also make rubber produce more rubber milk, and tobacco ripens early. This is really a magical gas.

Why is "bad fishing" sweet?

Students living in the south must know what "fishing bad" is, and it also has a name called liqueur. Although it smells like wine, it is not wine. It is made of timid rice or indica rice.

As we all know, rice is the main food for our people. Rice contains about 7% protein, and the main nutrient is 77% starch. These starches are the main source of human thermal energy.

We cooked rice, made medicated wine (commonly known as distiller's yeast) while it was hot, and made wine at the table. After nearly a day of heat preservation, we opened it and found that the taste changed, sweet and mellow, and it was very delicious. This is what the south calls sweet wine.

Why does rice become sweet wine after adding wine and medicine?

As we know, starch, glucose and other carbohydrates are all carbohydrates, and they are similar in molecular composition. Starch molecules are composed of many small molecules of glucose.

The medicated liquor contains amylase, which can promote starch hydrolysis and convert starch into sweet maltose. Amylase also exists in human saliva. When we chew rice in our mouth for a long time, we will feel sweet, which is the process of converting starch into maltose.

When making wine, maltose is converted into glucose by maltose invertase contained in medicinal liquor, and the other part is fermented into alcohol. In this way, the originally bland rice turned into a sweet liqueur.

"Smells bad and tastes sweet."

Stinky tofu is a kind of favorite food. "Smelling stinky and eating fragrant" is the unique flavor of stinky tofu. Stinky tofu tastes better.

Students who have never eaten stinky tofu can't imagine why such stinky tofu has so many diners. If you hold your nose and bite the bullet and try bravely, you won't ask why.

It turns out that stinky tofu stinks, but it is delicious. No wonder its smell can't stop.

Stinky tofu is made by processing soybeans into tofu with less water content and then inoculating Mucor seeds for fermentation. Stinky tofu is produced in summer, when the fermentation temperature is high and the protein in tofu is completely decomposed. The sulfur-containing amino acids decomposed by protein are further decomposed to produce a small amount of hydrogen sulfide gas. Hydrogen sulfide has a pungent smell, so stinky tofu smells strong.

And because protein in tofu is decomposed more thoroughly, stinky tofu contains a lot of amino acids. Many amino acids taste delicious. For example, the ingredient of monosodium glutamate is an amino acid called glutamic acid. So stinky tofu tastes extremely delicious and smells abnormal.

Stinky tofu is a patented product of China! Many famous foods are related to stinky tofu. For example, fried stinky tofu is a particularly famous snack.

Competition between alcohol yeast and baking powder

In our life, the dough for making cakes and steamed bread is usually fermented by adding yeast or yeast powder, so that the cakes and bread made will be looser and more delicious. Which is better, yeast or yeast powder?

Let's analyze it first.

Yeast contains a certain amount of maltase and sucrase, which cannot directly change a large amount of starch in flour. Flour itself contains a small amount of amylase, which can hydrolyze starch into maltose;

2(c6h 10o 5)n+nH2O NC 12 h22o 1 1

Starch maltose

Then, enzymes in yeast play a role in promoting the hydrolysis of trace sucrose originally contained in flour and newly produced maltose:

c 12h 22 o 1 1+H2O c 6h 12o 6

Sucrose glucose fructose

c 12h 22 o 1 1+H2O 2c 6h 12o 6

Maltose glucose

Yeast uses the energy provided by the oxidation of glucose and fructose to convert two sugars into carbon dioxide and water:

C6h12o6+6H2O → 6co216H2O10 calories.

The generated carbon dioxide gas can't leave the gluten network. When heating and steaming, carbon dioxide gas expands when heated, making the cake much bigger.

The food made by yeast is soft and delicious, with unique flavor and easy digestion. Yeast itself is rich in protein and vitamin B, which can increase the nutritional value of the finished product. So most flour products are fermented by yeast.

However, yeast fermentation often fails to achieve the expected effect on dough containing more sugar and oil, because sugar and oil have inhibitory effects on yeast. In addition, yeast fermentation takes a long time and is not done well. Either the dough doesn't rise, or the dough is sour and fermented too much. So you can also use baking powder instead of yeast to make cakes.

Baking powder is generally a mixture of sodium bicarbonate (NaHCO3, also known as baking soda) and sodium dihydrogen phosphate (NaH2PO4), and ammonium bicarbonate (NH4HCO3) is also useful. When yeast powder is mixed into dough, it generates carbon dioxide gas when heated, which makes flour products become loose and porous sponges. When used, the baking powder is not limited by fermentation time and can be used at any time, so it still plays the role of foaming and loosening dough containing oily polysaccharides. The disadvantage is that its alkalinity will destroy the vitamins in the dough, reduce the nutritional value, and also cause uneven mixing, resulting in too much alkali in some parts of the flour products and yellowing, which is inedible.

It can be seen that the two have their own advantages, but generally speaking, people always use yeast to ferment.

Don't let the color confuse your eyes.

We often see gold fonts or patterns on plastic diaries, binders and other items. This kind of gold lettering or pattern is ironed with gold powder. Is this gold powder made of gold? Of course not. Gold is so expensive that people will never use it to grind powder to decorate ordinary products. So, what is gold powder made of?

It turns out that the gold powder is made of copper-zinc alloy-proud silver copper. It's the same color as gold. People made brass in the Han dynasty, which was later called "fake gold", and the law at that time explicitly prohibited its use. We know that copper is purplish red, zinc is silvery white, and their alloy brass is as shiny as gold in Huang Chengcheng. Gold powder is made by mashing and polishing a thin piece of brass and a small amount of lubricant. Gold powder is widely used in paint and ink.

Similarly, silver powder used in paints and inks is not made of silver. Silver powder is made of aluminum, which is very cheap and has the same silvery white luster as silver. Aluminum powder is light in weight, stable in air, strong in light resistance and strong in light reflection ... This series of advantages makes aluminum powder win the title of "silver powder".

There are two ways to make aluminum powder. One method is to mix pure aluminum flakes with a small amount of lubricant and then mechanically mash them. Another method is to melt pure aluminum into liquid (the melting point of aluminum is low, only 660℃) and then spray it into fine aluminum powder.

A Misnamed "Moth Pill"

Clothes and books are in the cupboard. After a while, I opened the cupboard door and took a look. Ah, all good clothes and books have holes! Who did this?

This is dried by catfish, which mainly eats clothes and books, so people often call this moth "clothing fish". In order to get rid of these bad guys, people always put some "mothballs" in cabinets or boxes. Camphor is volatile and has a strong smell. When the squid smelled it, it had to retreat and run away.

However, camphor is more expensive and has more important uses in medicine (preparing cardiotonic agent) and chemical industry (making celluloid plastics). Therefore, the daily "moth balls" are not made of camphor, but of naphthalene.

The molecular composition of naphthalene is C 10H8. Pure naphthalene is a colorless flaky crystal, which, like camphor, can be directly evaporated into gas for sublimation. The smell of naphthalene can also stimulate octopus, so it is a good insect repellent.

Naphthalene is extracted from coal tar and is cheaper than camphor. However, you should pay attention to the use, and the sanitary balls you buy at any time are not very pure. It also contains some coal tar, which will stain clothes. Therefore, when in use, the sanitary balls should be wrapped in paper respectively, and then put into the cupboard or suitcase. After complete volatilization, the residual coal tar impurities will be absorbed by the paper and will not cause any trouble to the clothes.