1. Chemicals that accompany daily life-salt and iodine compounds
We know that the main component of salt is sodium chloride, which is the most commonly used condiment in people's lives. However, its function is not only to add < P > to the taste of food, it is a basic component of human tissues and plays an important role in ensuring normal physiological and biochemical activities and functions in the body. The functions of Na+ and Cl- in the body are intricately related to K+ and other elements. Its main function is to control the electrolyte balance in cells, tissue fluid and blood, so as to maintain the normal circulation of body fluids and control the acid-base balance in the body. Na+, K+, Ca2+ and Mg2+ also help to maintain the appropriate stress level of nerves and muscles. NaCl and KCl play a role in regulating the proper viscosity or consistency of blood; Acids that begin to digest certain foods in the stomach and other digestive compounds in gastric juice, pancreatic juice and bile are also formed by sodium and potassium salts in the blood. In addition, appropriate concentrations of Na+, K+ and Cl- also play an important role in the physiological process of retinal response to light. In addition, gargling with light salt water can not only treat and prevent oral diseases such as sore throat and swollen gums, but also prevent colds. (See Alkali Metals in Senior One Chemistry)
Potassium iodide, sodium iodide, iodate and other iodine-containing compounds are important reagents in the laboratory; In food and medical treatment, they are also important nutrients and medicines, which play an important role in maintaining human health. Iodine is an essential trace element in human body and an important component of thyroid hormone. In normal people, * * * contains 15 mg～2 mg of iodine, of which 7% to 8% is concentrated in the thyroid gland. Iodine in human body exists in the form of compound, and its main physiological function occurs through the formation of thyroid hormone. Therefore, the physiological functions and important functions of thyroxine are directly related to iodine. Lack of iodine in human body can lead to a series of biochemical disorders and abnormal physiological functions, such as endemic goiter, stagnant growth and development of infants and young children, and mental retardation. China is a serious iodine deficiency area in the world, and about 4 million people in the country are iodine deficient. The government has also taken some measures, such as providing iodized salt and other foods (such as eggs with high iodine content), iodizing well water and eating iodine-rich seafood, among which iodized salt is the most convenient and effective. In March 1991, our government made a solemn commitment to the international community: eliminating iodine deficiency disorders in Chinese mainland in 2. (See "Halogen Elements" in Senior One Chemistry)
Second, why do raw persimmons taste astringent
People born in the north or in the south will have such a life experience: the persimmons that are already as red as fire on the persimmon tree are still inedible. At first taste, it is still very astringent. Is this persimmon not fully ripe? Yes, but if the persimmons are completely ripe, it will be unfavorable for people to pick, transport and store them. Therefore, people often pick the persimmon when it has turned red, and put it on for a while, and it becomes a sweet and fragrant persimmon.
so, why does persimmon taste astringent?
It turns out that this is because raw persimmons contain tannins (also called tannins), which makes persimmons astringent.
In order to get rid of the astringency of raw persimmons, people have come up with many methods in their daily life practice. Some people cover the persimmon layer by layer with straw or pine needle leaves, or bury it in the leaves with pears. After a period of time, the astringency of the persimmon will be gone, and some people directly blanch the persimmon with hot water, and the astringency of the persimmon will be naturally removed. Now people have adopted the "carbon dioxide deastringency method", which is actually a summary of people's previous life experience. People seal persimmons in a room to increase the concentration of indoor carbon dioxide and reduce the concentration of oxygen. In this way, persimmons can't breathe normally, but breathe in the absence of oxygen. Under the condition of anoxic breathing, raw persimmon will produce acetaldehyde, acetone and other organic substances inside. These organic substances can turn tannins dissolved in water into substances that are difficult to dissolve in water, so persimmons are no longer astringent, but sweet and fragrant.
if you also have some raw persimmons that want to "get rid of astringency", you can put them in a plastic bag and tie the bag tightly. Generally, after a few days, the astringency can be removed.
3. "Smells bad and tastes good"
Stinky tofu is a kind of food that people like. "Smelling stinky and eating fragrant" is the unique flavor of stinky tofu. The stinky tofu tastes better.
Students who haven't eaten stinky tofu can't imagine why so smelly stinky tofu has so many diners. If you hold your nose and bite the bullet and try it bravely, you won't ask why.
It turns out that stinky tofu is very smelly, but it's delicious. No wonder its smell can't be stopped.
stinky tofu is made by processing soybeans into tofu with less water content, and then inoculating Mucor species for fermentation. Stinky tofu is produced in summer, when the fermentation temperature is high and the protein in tofu is decomposed thoroughly. The sulfur-containing amino acids decomposed by protein were further decomposed, resulting in a small amount of hydrogen sulfide gas. Hydrogen sulfide has a pungent smell, so stinky tofu smells strong.
Because protein in tofu is decomposed more thoroughly, stinky tofu contains a lot of amino acids. Many amino acids have delicious taste. For example, the ingredient of monosodium glutamate is an amino acid called glutamic acid. Therefore, stinky tofu tastes extremely delicious and smells abnormal.
stinky tofu is a patented product in China! Many famous foods are related to stinky tofu, for example, fried stinky tofu is a particularly famous snack.
iv. vinegar (acid)
the chemical name of vinegar is acetic acid, and its molecular formula is CH3COOH. Vinegar is not only a condiment, but also has many uses: 1. When cooking vegetables, putting vinegar is not only delicious, but also has the function of protecting vitamin C in vegetables (because vitamin C is not easy to be destroyed in acidic environment). 2. When cooking ribs, chicken and fish, if you add a little vinegar, calcium and phosphorus in bones can be dissolved in soup in large quantities, thus greatly improving the absorption rate of calcium and phosphorus in human body. 3. People suffering from low-acid gastropathy (too little gastric acid secretion, such as atrophic gastritis) can not only increase their appetite, but also treat the disease if they often use a small amount of vinegar as seasoning. 4. When the fish is not fresh, cooking with vinegar can not only remove the fishy smell, but also kill bacteria. 5. Vinegar can be used as a good medicine to prevent dysentery. Dysentery bacteria will die as soon as they meet vinegar, so eating more vinegar in summer when dysentery is prevalent can increase the effect of killing dysentery bacteria in the stomach. 6. Vinegar can also prevent influenza. Close the indoor doors and windows tightly, pour vinegar into the pot and boil it until it is dry, which can kill germs. 7. When polishing shoes, drop a drop of vinegar to make shoes bright and lasting. 8, copper, aluminum used old, with vinegar after cleaning, can restore luster. 9. 2 minutes before killing chickens and ducks, pour some vinegar into the chickens and ducks, and it will be easy to pluck the hair. 1. The clothes are stained with fruit juice. Soak them in vinegar and rub them off. 11. Soaking the scale in the thermos bottle with vinegar can achieve the purpose of descaling. 12. Towels are prone to mildew and odor in summer. Washing towels with a small amount of vinegar can eliminate odor. (See "Derivatives of Hydrocarbons" in Senior Two Chemistry)
V. Drugs that are not still-cigarettes
Introduce the structure, nature and harm of harmful components produced during smoking from a chemical point of view. The substances harmful to human body after cigarette lighting can be roughly divided into six categories: (1) Aldehydes, nitrides and alkenes, which can stimulate the respiratory tract. (2) Nicotine can stimulate sympathetic nerve and cause intimal damage. (3) Amines, cyanide and heavy metals are all toxic substances. (4) Phenylpropylpyrene, arsenic, cadmium, methylhydrazine, aminophenol and other radioactive substances. These substances are carcinogenic. (5) Phenolic compounds and formaldehyde, etc., which have the function of accelerating cancer. (6) carbon monoxide can reduce that ability of red blood cell to transport oxygen to the whole body. Recent research by Japanese scholars shows that smog also contains the most toxic compound "dioxin" among the known substances. They can cause and worsen various diseases, such as cancer, pneumonia, tracheitis, hypertension, hyperosteogeny, various cardiovascular and cerebrovascular diseases, asthma and infertility. According to the information provided by the World Health Organization, about 1 million people worldwide die of diseases related to smoking every year. Teenagers are in the period of growth and development, respiratory mucosa is easy to be damaged, and smoking is more harmful. According to the survey, the incidence of lung cancer is 17 times higher for people who start smoking before the age of 15 than for non-smokers. Therefore, the code for primary and secondary school students in China stipulates that students are not allowed to smoke. (Knowledge runs through the organic matter in senior two chemistry)
6. Don't let colors confuse your eyes
We often see gold lettering or gold patterns on plastic diaries, binders and other articles. This gold lettering or gold pattern is ironed with gold powder. Is this gold powder made of gold? Of course not. Gold is too expensive, and people will never use it to grind powder to decorate ordinary products. So, what is gold powder made of?
It turns out that gold powder is made of copper and zinc alloy-Yintong. Its color is exactly the same as that of gold. In the Han Dynasty, people made brass, which was later called "fake gold", and the law at that time explicitly prohibited its use. We know that copper is purplish red and zinc is silvery white, and their alloy, brass, is as Huang Chengcheng and shiny as gold. 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 paints and inks.
similarly, silver powder used in paints and inks is not made of silver. Silver powder is made of aluminum which is cheap and has the same silvery white luster as silver. Aluminum powder is light in weight, stable in air, strong in blocking light, and strong in reflecting light ... This series of advantages made 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 mash them mechanically. Another method is to melt pure aluminum into liquid (the melting point of aluminum is low, only 66℃), and then spray it into fine aluminum powder.
Seven, the right-hand man in life:
(1) Remove the stains on clothes:
1. Sweat stains: Method 1: Soak the clothes with sweat stains in 1% salt water for a while, and then wash them with soap. Method 2: Add a small amount of carbamine [(NH4)2CO3] and a small amount of edible alkali [Na2CO3 or NaHCO3] into a proper amount of water, stir and dissolve, then soak the clothes with sweat stains in it for a while, and then rub them repeatedly.
2. Oil stains are dripped with gasoline or alcohol, and the oil stains will disappear after the gasoline (or alcohol) evaporates.
3. Blue ink stain: Method 1: Add a small amount of carbamine [(NH4)2CO3] and a small amount of edible alkali [Na2CO3 or NaHCO3] into a proper amount of water, stir and dissolve, then soak the clothes stained with blue ink in it for a while, and then rub it repeatedly. Method 2: soak the part with blue ink stain in 2% oxalic acid solution for a few minutes, and then wash it off with detergent.
4. Blood stains contain protein, but protein is not easy to dissolve when heated, so hot water cannot be used to wash blood stains. Method 1: Soak the bloodstained part in hydrogen peroxide or bleaching powder water for a while, and then scrub it. Method 2: Chop the radish, sprinkle with salt and stir evenly. After ten minutes, squeeze out the radish juice, soak the blood-stained part in radish juice for a while, and then rub it.
5. The newly infected juice stains are soaked in salt water and then washed with soap. If it is infected for a long time, you can use the first method of washing sweat stains.
6. Rust stain: Add a little oxalic acid to hot water, stir until all the oxalic acid is dissolved, soak the parts with rust stain in oxalic acid solution for ten minutes, and then scrub with soap.
7. Tea stains: Soak the parts with tea stains in saturated salt water, and then scrub them with soap.
(2) Clever descaling of the kettle
1. Put the empty kettle on the fire and boil off the water of the scale. When the scale at the bottom of the kettle is cracked, take it off quickly and put it in cold water, and the scale at the bottom of the kettle will fall off due to thermal expansion and contraction. 2. Put a group of mask cloth in the pot of boiling water, and the scale will be adsorbed by the mask cloth, so it is not easy to scale on the pot. 3, there is scale in the pot of boiling water, you can put some vinegar, add water, and boil for a while, the scale can be removed. 4. When boiling water in an aluminum pot, put a spoonful of baking soda and boil it for 1 minutes, and the scale can be removed.
Eight, a kind of laxative-phenolphthalein
Anyone with a little knowledge of chemistry knows that dropping one or two drops of a certain solution into an aqueous solution of sodium hydroxide will immediately show a bright red color. This is the famous indicator-phenolphthalein. If a certain amount of sulfuric acid is added to the red solution, the red solution will become colorless again.
phenolphthalein is one of the most commonly used acid-base indicators, and it is dissolved in alcohol when used. It will appear red when it meets alkali solution, but it is still a colorless solution in neutral or acidic solution.
However, people who have studied chemistry may not know that phenolphthalein is still a good medicine for doctors to treat diseases! In medicine, phenolphthalein is a laxative. Phenolphthalein can gently stimulate the intestinal wall, enhance intestinal peristalsis and promote defecation, which is very effective for habitual constipation. "Fruit guide" contains phenolphthalein.
9. Eggs, milk-first aid for poisoning
Perhaps you have heard that eggs, milk and soybean milk can be used as first aid drugs for poisoned patients. What is the reason?
Eggs, milk and soybean milk are rich in nutrition and contain a lot of protein. Protein has a characteristic that it will precipitate when it meets heavy metal ions, such as mercury and aluminum. When heavy metal ions enter the human body, protein, which constitutes the organs and blood of the human body, will precipitate and lose its function, resulting in poisoning. At this time, after giving the patient milk, raw egg white and soybean milk, the rich protein in food will interact with heavy metal ions, thus reducing the toxicity of poisoning. At the same time, these foods also provide nutrition for patients who are poisoned and weak, which is helpful for patients to recover.