1. Thick neck disease (thyroid enlargement) and cretinism (cretinism) are common in mountainous areas. Doctors recommend eating more kelp and performing food therapy. The cause of the above disease is a lack of one element in the human body: iodine.
2. The metal used to make metal foil (metallic paper) for packaging cigarettes and candies is: aluminum.
3. The melting point of gold is 1064.4°C, and there are many metals with higher melting points than it. The melting point is about 3 times higher than gold
The metal usually used to make incandescent light bulb filaments is: tungsten.
4. A woman gave a gold and silversmith an old gold ring of 6.10 grams to be processed into a pair of earrings. She was afraid that the craftsmen would steal the gold or adulterate it, so she stayed by her side and never left. She watched the craftsman heat, beat and put the ring into a liquid. After many times of processing, a pair of beautiful earrings were completed. A few days later, the pair of earrings were weighed on a scale and found to be only 5.20 grams. So the liquid used by craftsmen to steal gold is: aqua regia.
5. The black substance in the black and white photo is: silver.
6. Many chemical elements play an important role in people's life activities. Without them, people will get sick.
For example, rickets that children often suffer from are due to a lack of: calcium.
7. A lamp made by filling a quartz tube with a certain gas can emit light hundreds of millions of times stronger than a fluorescent lamp when energized. Therefore, it is called "artificial lamp". "Little Sun". The gas filled in this lamp is: xenon.
8. Lighting a fire for heating or using a water heater to bathe in a room with closed doors and windows often produces a colorless, odorless substance
that can easily combine with human hemoglobin (Hb) to cause poisoning. The gas is: CO.
9. The destruction of the earth's atmosphere will form a hole in the ozone layer, causing damage to the ozone layer that protects people from the sun's ultraviolet
damage, causing the occurrence of skin cancer and other diseases, and destroying To achieve the ecological balance of nature
. The main cause of the hole in the ozone layer is Freon leakage in refrigerators.
10. The concentration of medical disinfectant alcohol is: 75.
11. The sodium chloride contained in normal saline commonly used for hospital infusion is roughly the same as the concentration of sodium chloride in blood
etc. The mass fraction of NaCl in physiological saline is: 0.9.
12. After the "gunpowder paper" (fire) in the starting gun is fired, the white smoke produced is: phosphorus pentoxide.
13. Naphthalene sanitary balls become smaller when placed in the closet. This is because naphthalene slowly sublimates at room temperature.
14. If a person’s skin is itchy or red and swollen after being bitten by a mosquito, the simple solution is to apply dilute ammonia or sodium bicarbonate
solution.
15. Because a certain gas A accumulates excessively in the atmosphere, the earth's infrared radiation cannot penetrate the atmosphere, thus
causing the atmospheric temperature to rise and producing the "greenhouse effect". Gas A is: carbon dioxide.
16. Acid rain refers to rain, snow or other forms of atmospheric precipitation with a pH value less than 5.6. Acid rain is a manifestation of air pollution. The main cause of acid rain is: sulfur dioxide, nitrogen dioxide, etc. released from burning fuel.
17. The iron wire bought in the hardware store is coated with an "anti-corrosion" metal: zinc.
18. An all-steel watch means that its case and back cover are all made of stainless steel. Stainless steel is shiny and will not rust. The reason is that chromium and nickel are added during the steelmaking process.
19. Photoelectric tubes made based on the property of emitting electrons from a metal when exposed to ordinary light are widely used in movie
recorders and video cameras. The metal used to make photoelectric tubes is: cesium.
20. When the hospital radiology department examines diseases in the esophagus, stomach and other parts of the body, the "barium meal" imaging method is commonly used. The substance used as a "barium meal" is: barium sulfate.
21. Mr. Hou Debang, my country’s world-famous alkali-making expert, invented Hou’s alkali-making method in 1942. In addition to being used in industry, a certain amount of this alkali is also added to fried dough sticks and steamed buns in daily life. The chemical name of this base is: sodium carbonate.
22. Some door and window frames of modern buildings are made of duralumin that is electroplated to become bronze. The composition of the duralumin is: Al-Cu-Mg-Mn- Si alloy.
23. Barium chloride is highly toxic, with a lethal dose of 0.8 grams. If accidentally swallowed, in addition to swallowing a large amount of egg white to detoxify
you should also take a certain amount of antidote. The antidote is: magnesium sulfate.
24. Printed circuit boards are commonly produced by chemical etching. This chemical corrosive is: ferric chloride.
25. Liquefied petroleum gas has already entered households. Its main ingredients are: propane and butane.
26. The main component of natural gas is methane. If a stove that uses natural gas as fuel is converted to burn liquefied petroleum gas
, the correct measure to take is to increase the amount of air entering or reduce the amount of liquefied petroleum gas entering.
27. After the gas tank containing liquefied gas is used up, you will often hear the sound of sloshing water when shaking, but this kind of liquid with water sound
must not be poured out without permission. The main reason is that this liquid is a hydrocarbon with a slightly higher carbon content, and is as easy to burn as gasoline, and accidents such as fires may occur if it is dumped accidentally.
28. The audio tape is made of a base made of fibers such as acetate fiber and polyester fiber, which is evenly coated with a layer of magnetic material - magnetic powder. The main substance for preparing magnetic powder is: ferric oxide.
29. Masons use slaked lime to paint walls, and often add a small amount of coarse salt to the lime. This is to take advantage of the deliquescence of the easily deliquescent substances contained in the coarse salt
, which is beneficial to carbon dioxide. absorption. This substance that is easy to dehumidify is: magnesium chloride.
30. The reason why the original works of ancient Chinese calligraphers can be preserved to this day: the use of ink or carbon ink makes the handwriting
not fade for a long time. This is because the chemical properties of carbon are stable.
31. The author's seal is often left on calligraphy and painting. The seal is bright and ruddy. This is because the red ink pad contains red substances that do not fade
and are chemically stable. Should be: cinnabar (mercuric sulfide).
32. With the improvement of people's living standards, gold jewelry has become people's favorite decoration. The unit of purity of gold products is expressed in K. 24K usually represents pure gold or red gold, and the actual gold content is more than 99%. Gold nibs and gold watch cases are both 14K, and their usual gold content is: no less than 56.
33. Smoking can cause bronchitis, cardiovascular disease, and induce lung cancer, oral cancer, gastric cancer, bladder muscle cancer
and other cancers, so smoking is a chronic suicide. The World Health Assembly stipulates April 7 every year as "World Smoking Smoking Day
". According to analysis, the most harmful substances in tobacco mainly include: nicotine and benzo(a)pyrene.
34. When a submarine sails in deep water for a long time, the best substance used to supply the crew with the oxygen needed for breathing is: sodium peroxide.
Sodium peroxide.
35. The glass pieces used in color-changing glasses can turn darker under sunlight because: appropriate amounts of silver halide crystals and copper oxide are added to the glass.
36. Lead poisoning can cause anemia, headache, memory loss and digestive system diseases. Acute poisoning can cause chronic brain damage and is often life-threatening. The main source of lead pollution in urban air is: vehicle exhaust.
37. The cooling water contained in the water tanks of cars and diesel engines will cause the water tanks to burst after freezing in winter. In order to prevent freezing, a small amount of ethylene glycol is often added.
38. The gray manganese oxygen or PP powder in the hospital is: potassium permanganate.
39. The preservative in orange drinks and cans is sodium benzoate.
40. The main components of scale in kettles, thermos bottles and boilers are: calcium carbonate and magnesium hydroxide.
41. The substance that cannot be used to make wine is: soybeans. Substances that can be used to make wine are: millet, corn, sorghum, sweet potato, etc.
42. After strenuous exercise, you feel sore all over your body. This is because lactic acid is added to the muscles.
43. Among nutrients, the one with the highest caloric value and the longest stay time in the gastrointestinal tract after eating (satisfying) is: fat
Fat.
44. MSG is also called monosodium glutamate. It has a strong meaty flavor. Its chemical name is: monosodium 2-aminosuccinate (monosodium glutamate ).
45. After the frost, vegetables, radishes, etc. taste sweet. This is because the starch in the vegetables is hydrolyzed by the enzymes in the plants to produce: glucose.
46. Why did the ancients "spend three days fishing and two days drying the nets"? Because fishing nets in the past were made of hemp fiber,
Hemp fiber absorbs water and easily swells, and it is easy to rot when it is wet. Therefore, the fishing net was used for two or three days and then dried for two days to extend the length of the fishing net.
life span. There is no need to do this now because the material used to weave fishing nets is now generally nylon fiber.
47. When theatrical performances are broadcast on TV, we often see smoke rising from the stage. The commonly used smoking agents
are: ethylene glycol and dry ice.
48. When raising goldfish with tap water, the water needs to be exposed to the sun for a period of time before pouring into the fish tank. The purpose is to:
Decompose hypochlorous acid in the water.
49. If cooking oil is stored for a long time, the best container is: glass or ceramic container.
50. The reason why non-stick pans do not stick to food is because the bottom of the pan is coated with a special substance: "Teflon",
its chemical name is polytetrafluoroethylene , commonly known as the Plastic King.