1. Why is tap water not suitable for direct fish culture in goldfish pond?

Reason: Tap water is generally disinfected with chlorine, and chlorine and other substances are unfavorable to the growth of goldfish, so it is best to use tap water in pots and dry it in the sun for a day or two before using it to raise fish.

2. Why would someone use plant ash to clean some cabinet appliances?

Reason: plant ash contains a small amount of potassium carbonate, so plant ash's aqueous solution is alkaline and has a certain decontamination effect.

3. Why do you want to soak some valuable medicinal materials in medicinal liquor?

Reason: Wine can slowly dissolve some useful substances in medicinal materials. When people drink medicinal liquor, they can absorb the beneficial components in medicinal materials and play the role of medicine. However, it should be noted that some people are allergic to alcohol and should drink according to their abilities.

4. Why do you advocate using unleaded gasoline now?

Reason: In the past, in order to reduce the vibration caused by severe combustion of gasoline, lead-containing substances were added to gasoline. However, lead is a heavy metal, which is toxic. After burning, it will be discharged together with tail gas, seriously polluting the environment.

5. Why is the newly-built house not suitable for immediate occupancy?

Reason: The slaked lime used to build a house reacts with carbon dioxide in the air during the maintenance process to generate water, so the newly built house is relatively humid, and it is best to stay for one or two months. In addition, the newly renovated room will emit some harmful gases because of various paints and chemical coatings, and it will take 15 -30 days to move in.

6. Another function of rust remover

Another function of "rust remover" is to burn honeycomb coal in winter. Because coal is wet, black water will flow out of the chimney after ignition. This kind of water can't be washed off with washing powder and soap, but it can be washed off with a small amount of "rust remover"

7. Liquor except edible oil.

After eating, there are always oil stains on the dining table, which is difficult to clean with a hot rag. If you pour a little white wine on the dining table and wipe it back and forth with a clean rag several times, the oil stain can be removed.

8. White iron drums cannot store acidic food.

Iron drums are galvanized iron drums. Zinc is a white, soft and shiny metal, which is easily soluble in acidic solution. If acidic foods and drinks are prepared or stored in iron drums or other galvanized utensils, zinc will be dissolved in food in the form of toxic organic acid salts, which may cause poisoning after people eat it. Therefore, when using galvanized containers, do not use them to hold acidic dishes, soup, wine, juice, milk and other beverages.

9, in addition to juice three methods

For the newly infected juice, sprinkle some salt first, wet it gently with water, and then soak it in soapy water for cleaning. For slight fruit stains, you can wash them with cold water. If you can't wash it clean once, wash it again until it is clean. If the pollution is serious, you can use dilute ammonia water (1 part ammonia water to 20 parts water) to neutralize the organic acids in the juice, and then wash it with soap. Woolen clothes can be washed with tartaric acid solution. Silk can be washed with citric acid or with soap and alcohol solution. Drop a few drops of vinegar on the juice stain, rub it with your hands a few times, and then wash it with water.

10 Chemical Examples in Life When steaming steamed bread, the dough becomes sticky and produces CO2. Natural gas combustion. It is necessary to use detergent when washing things. Carbonated soda. Everything to take medicine is necessary. All disinfection is necessary. Digestion and absorption. Combustion, carbonization. Rust removal. Emotional changes, psychological changes, physiological phenomena.

A chemistry test in Grade Three (an example of chemistry in life) used lime as marble.

Make marble with lime

Make marble with lime

Make marble with lime

The paper on chemistry in life wants a mystery about Napoleon's death.

Napoleon, a famous French strategist, commanded thousands of troops on the battlefield before his death, and made outstanding achievements. The so-called storm was temporary, but the cause of his death has always been a historical mystery.

For nearly a century, public opinion around the world has different opinions on Napoleon's death. At that time, the French official death report determined that he died of gastric ulcer, while some people thought that he died of political murder, and some even thought that he was murdered by his rival in love in sexual matters. In recent years, British scientists and historians have collected Napoleon's hair by means of modern science and technology, and analyzed its composition and content. At the same time, they also conducted a field survey on St. Helena where Napoleon was exiled after the defeat of the Battle of Waterloo, and obtained the wallpaper of Napoleon's imprisoned room. After research, British scientists published an analysis report and announced that the "murderer" who killed Napoleon was arsenic. The scientific name of arsenic is arsenic trioxide, which is a highly toxic substance and can enter the human body through air, water and food. Napoleon didn't eat arsenic before he died, and no one murdered him with arsenic (because eating arsenic would immediately kill him, and Napoleon died in prison). Therefore, when British scientists announced this conclusion, people were very surprised. So how did arsenic poison Napoleon? It turned out that in the room where Napoleon was imprisoned, wallpaper containing arsenic was stuck on the walls around him. In a dark and humid environment, wallpaper will produce a gas containing high concentration of arsenic, which will pollute the air in this room and accumulate over time, eventually causing Napoleon to die of chronic arsenic poisoning. When examining Napoleon's hair, the British Institute of Forensic Medicine found that the arsenic content in his hair was 13 times higher than that of normal people. According to the records of the prison guards that year, "Napoleon lost his hair at the last stage of his life, his teeth showed his gums, his face was pale, his feet were swollen, and his heart beat violently." This symptom is completely similar to arsenic poisoning. So the conclusion that Napoleon died of arsenic poisoning is easy to understand.

What are some examples of chemistry in daily life? Hello: disinfect clothes with 84 disinfectant.

Make dough with baking soda.

Use gas as fuel.

When food is digested, protein is decomposed into amino acids and starch into glucose.

The plastics used are all high molecular organic substances, which may be converted from petroleum.

Rust is the oxidation reaction of iron and oxygen, and drinking vinegar after drinking too much wine is the neutralization reaction of acetic acid and ethanol, and so on.

I hope it will be helpful to your study.

Please use O(∩_∩)O if you are satisfied. Thank you.

Welcome to ask O(∩_∩)O~

I wish you progress in your study ~

Examples of chemical changes, primary schools, should be simple, life examples. Hehe, if you put the egg shell into the old vinegar, you will see many bubbles on the surface of the egg shell. This is very common and simple, right? Why? Because vinegar is mainly composed of acetic acid except water, and the egg shell is full of calcium carbonate. When acids come into contact with calcium carbonate, they react and release carbon dioxide, which is bubbles.

Give some examples of physical chemistry in life, the more the better ~ When it comes to chemistry, many people immediately think of chemistry courses offered in middle schools or universities or think that "chemistry" is a matter for chemists and scientists, which has nothing to do with me. However, in our life, chemistry is everywhere.

For example, steel rusting, burning objects, protein poisoning, acid rain and so on are all chemical phenomena.

So, what is chemistry? Generally speaking, it is a phenomenon that one substance and another substance synthesize another substance with new characteristics.

For example, steel rust is a chemical phenomenon. As we all know, ordinary ironware will rust in a month or two if it is placed in a humid and ventilated place. You can go to the museum, where all the ironware on display is rusty. Iron rusts because it contains impurity carbon and reacts with oxygen in the air at room temperature. Under the action of water (water vapor in the air), oxygen (symbol O) in the air enters the interior of iron and reacts with iron (Fe) to synthesize another substance-Fe3O4. Water is the chief culprit of iron rust. Chemists have proved that iron will not rust for several years if it is put in anhydrous air. If you put a piece of iron in a boiling, closed distilled water bottle (there is no air in the bottle), it will not rust. Only when oxygen and water attack iron at the same time will iron rust. In addition, carbon dioxide (CO2) in the air will rust iron when it meets iron. Rust is loose and soft, like a sponge, which will constantly absorb water and increase the rusty area of iron. The corrosion rate is accelerating. I have done experiments, and after a piece of iron is completely rusted, its volume is several times larger than the original. Some metals and metals also rust (that is, "oxidation"). For example, if aluminum pot is used for a long time, its surface luster will gradually disappear and be covered with a layer of "aluminum rust", which is "aluminum rust"

This is alumina-it is formed by the reaction of aluminum with oxygen in the air. In order to reduce the rust of iron, after primary refining, smelters further remove the carbon contained in pig iron by adding oxygen to ordinary iron. After such smelting, the efficiency and antioxidant reaction of iron have been improved. At this time, iron became "steel".

People have come up with various ways to protect steel. The most common method is to "dress" iron-paint the surface of iron or plate it with other metals that are not easy to rust. For example, cars are sprayed with shiny paint, heating pipes are painted with aluminum paint, tinplate for canning is coated with tin sheet, and the surface is coated with zinc. Its purpose is to isolate steel from water and air so that it cannot react chemically.

As we all know, objects need fire to burn. So, how did cases like the above and those large-scale forest fires happen without kindling?

It turns out that whether an object burns or not requires not only air (oxygen), but also a temperature limit, which is the so-called "ignition point". That is, when it reaches a certain temperature, the object will burn without catching fire. Dry paper and trees have very low ignition points, and it is easy to spontaneously ignite without fire at high temperature. This is how the above cases and forest fires are produced.

The combustion of objects seems to have nothing to do with chemistry, but in fact it is very closely related. Combustion is a violent chemical reaction phenomenon: one substance oxidizes with air (oxygen) at high temperature to produce another substance (such as carbon dioxide). In the process of oxidation reaction, huge energy-heat energy is released, which is the flame we see. Carbon contained in paper, wood and leaves reacts with oxygen in the air at high temperature to produce a gas called carbon dioxide (symbol CO2).

The mass floated into the air and disappeared. Therefore, after gasoline burns, there is no paper, clothes or wood, and only a small amount of faint ash remains after burning. These ashes are other impurities in the object that cannot react with oxygen. The combustion of coal, gasoline, clothes and other objects is similar.

Knowing the principle of combustion, people have come up with various ways to prevent fire and put out fire. For example, high temperature resistant and fireproof materials are used to build houses, and foam extinguisher is used to put out fires in furniture. If the oil pan burns because of high temperature when you are cooking, don't panic first, just cover the lid immediately and the fire in the oil pan will go out. Don't be afraid of electrical aging or short circuit fire. Immediately cover the burning electrical appliances with a thick quilt to put out the fire. Please think about it. What is the reason? (The fire in the oil pan will make the fire stronger, and the fire in the electric appliance will hurt people. ).

It is also a chemical reaction phenomenon that matches used by people do not catch fire and spontaneously ignite in friction. There are sulfur particles and gunpowder in the match head. "Peeling" is made of rough paper coated with a layer of phosphorus. Sulfur, gunpowder, phosphorus, etc. Are flammable substances with low ignition point. When making a fire, just scrape the match head on the phosphorus paper. At this time, phosphorus and sulfur will generate high temperature due to friction, and the stick will be ignited. However, it is not safe for old matchsticks to rub against the wall. The little girl's matches in the famous fairy tale "The Little Match Girl" are this kind of matches.

1. Why does fried shrimp oil swell?

Shrimp slices are made of cooked starch. When making, some air is enclosed in many micropores formed inside. Because these micropores are very small, we can't see them with the naked eye. Put the shrimp slices in a hot oil pan, on the one hand, the cooked starch will soften when heated, on the other hand, the air in the micropores will expand rapidly when heated. The air inside was forced out, and the cooked starch outside became soft again, and the shrimp slices immediately swelled. When the temperature drops, the starch outside becomes hard, and the shrimp slices become crisp and chubby.

2. Why do women usually float on the water more easily than men?

In summer, we went swimming together, and several male students tried to float on the water. They found that their feet always sank. And several female students next to them can float on the water. Why is this?

We know that the average human density is about 1.0× 103kg/m3. When people hold their breath, the density of people is less than that of water, so people should be able to float on the water. However, the density of men is higher than that of women. This is because the proportion of fat in women is higher than that in men. Female body fat accounts for about 20% of body weight, and male body fat accounts for about 15% of body weight. In this way, women are more likely to be lifted by water than men.

In addition, from the perspective of body shape, the difference between men and women also determines that women are more likely to float on the water than men. The biggest size of a man's whole body is his chest. Therefore, the point of action of water on his buoyancy is near his lungs. Because of the gravity of his feet, his center of gravity is near his hips, which deviates from his lungs. This pair of forces does not act in a straight line, resulting in a turning effect.

The biggest part of a woman's whole body is her hips, the point of buoyancy is near her hips, and the center of gravity is a little above her hips. The lines of action of these two forces are very close. With a slight adjustment of human posture, buoyancy and gravity can be in a straight line, and the two forces can be balanced, so that women can float on the water more stably than men. If a person wants to float on the water smoothly, he can raise his arms above his head and extend them horizontally, so that his center of gravity can move up to reduce the sinking tendency of his feet.

3. Why is there a circular sink above the pickle jar?

There is a jar for making pickles, and there is a circular sink above the ceramic container. Put pickle soup and sauerkraut in the jar, put the bowl upside down on a circular sink, and add a proper amount of water to the sink to make kimchi.

Pickling pickles is the process of processing vegetables by lactic acid bacteria, which are anaerobic bacteria, that is to say, pickling pickles should be carried out under the condition of isolating air. A bowl is upside down on the circular sink. After adding a proper amount of water, the sink is divided into two containers with communicated bottoms by the bowl rim, that is, the communication device. According to the principle of communicator, the water surface inside and outside the bowl rim is horizontal. So the air inside and outside the altar was separated by water. Air can't enter the jar, which ensures the normal chemical changes in the jar.

In addition, the chemical change in the cylinder produces gas, which can also be discharged from the cylinder through the water at the bottom of the annular water tank when the air pressure in the cylinder is greater than that outside the cylinder.

It can be seen that the annular water tank has two functions of isolating air and one-way valve, which plays a key role in the pickling process of kimchi. If your family uses a pickle jar to make pickles, don't forget to add water to the circular sink. Because the sink is shallow and can't hold much water, it is easy to evaporate, which makes the gas inside and outside the pickle jar communicate with each other and makes the pickle soup moldy and grow a layer of white hair. What a pity!

4. Why do wet socks stick to my feet?

Socks are on your feet, your feet are in the water, and your socks are soaked. It's hard to take it off at this time, just like sticking to your feet.

Some people say that this is because water is sticky, and it is water that sticks socks and feet together. This statement is not accurate. It is the air that sticks socks and feet together, and the attraction between water molecules also plays a role.

In the past, there was a layer of air between dry socks and feet, and both the inner and outer layers of socks were under atmospheric pressure, so it was not necessary to overcome the atmospheric pressure when taking off socks. Socks are soaked, and the air between socks and feet is exhausted. When the gap between socks is filled with water, it becomes a closed whole. The outside air can't enter between the socks and the feet, and the socks are tightly pressed on the feet by the atmospheric pressure from outside the socks. So it is not easy to get rid of atmospheric pressure. It's not the socks that stick to your feet, but the pressure on your feet.

In addition, there is water on socks and feet, and there is gravity between water molecules. Overcome the attraction between water molecules when you take off your socks. For the above two reasons, it is more difficult to take off wet socks than to dry them.

5. Why can kites fly into the sky?

There are more kites in Beijing every spring. Whether it is Tiananmen Square or the open space next to the newly-built overpass, many adults and children put colorful kites into the sky with great interest. These kites are flying in the blue sky, which is very spectacular. But do you know why kites fly in the sky?

Some people say that kites have been blown into the sky by the wind, which is not entirely correct. The paper was blown to the sky by the wind and soon fell to the ground by itself. The kite is pulled by the string and has a certain angle with the direction of the wind. When the wind blows on the kite, the kite gives the wind a force to change its direction. According to Newton's third law, action and reaction are equal in magnitude and opposite in direction, and act on two interacting objects respectively. The wind also gave the kite a reaction force, which made it float upward and far away. At this time, as long as the string of kite is properly loosened, the wind will send the kite into the sky. When people tighten the string, the pulling force of the string on the kite is opposite to that of the wind, so that the kite will not go far. Kites are suspended in mid-air under these two forces.

If the wind speed is too small, the force of the wind on the kite is not enough to support the gravity of the kite and the tension of the thin thread, and the kite will fall from a height. Generally, the wind is weak near the ground, so we must try our best to make the kite reach a certain height before it can automatically rise to a higher place and the line floats in the air. Therefore, people often pull kites to run against the wind, or climb high to make the wind speed blowing on kites increase and let kites fly into the sky.

6. Why do flight attendants hand out chewing gum to passengers?

When you travel by plane, the flight attendants always give you gum before the plane takes off. Is this to add sweetness to your trip? No, it's to relieve your discomfort during the flight.

As we know, the density of atmospheric air changes, and the atmospheric pressure decreases with the increase of height. Although the engine room of our large civil airliner is sealed, the air pressure in the engine room will still change greatly during the take-off, landing and navigation of the aircraft.

When people are on the ground, the air pressure on the ground is about 1 atm, and the air pressure in the eustachian tube and the internal auditory canal is also about 1 atm. When the plane rises to the sky, the air pressure in the cabin decreases, and the inner ear and eustachian tube are sealed by an atmospheric pressure gas, resulting in a pressure difference between the inside and outside of the eardrum, which makes people feel dizzy, nausea and even vomiting. At this time, as long as you open your mouth to chew and swallow, the eustachian tube will open and communicate with the air, so that the air pressure in the inner ear is the same as that in the cabin, and the pressure difference on the eardrum will disappear. In order to help you open the eustachian tube and reduce or even eliminate the discomfort caused by the change of air pressure, the flight attendant gave you chewing gum to help you tide over this difficulty easily and sweetly.

From this example, we can know that when the air pressure around you changes dramatically, it is one of the good ways to protect your ears by actively opening your mouth to keep the pressure inside and outside the ear consistent.

7. Why isn't the window behind the bus open?

When you were sitting on a speeding bus, did you find that the back window of the car was always closed? What happened? Why not open the back window of the car in hot summer?

If a small fish swims in the vast sea, there will be no waves on the water. If a big whale comes, it will stir up rolling waves. This is because the whale's body is very big, and it occupies a large volume. When he swims forward, there will be water to replenish where he left. Therefore, huge waves often appear at the tail of whales.

The same is true for buses, where the body has just passed, there must be air supplement. So the air will come from the side and behind these places, forming a vortex. The vortex of air rolled up the dust on the ground, followed closely behind the car and rolled up a big ash column; This is the dust that we see flying behind the car. If we open the window at the back of the bus, the air will inevitably be filled with dust and pushed into the car. So most of the windows behind buses are closed.

8. Why can the automatic flushing water tank in public toilets flush regularly?

In public toilets, it is common to see a device that automatically discharges water at regular intervals, which is a sanitary device made according to siphon phenomenon.

Siphon phenomenon is very common in daily life. Take a long rubber tube filled with water, hold both ends by hand, insert one end into the bucket on the table, and let the other end of the rubber tube hang outside the bucket. The rubber tube hanging outside is longer. Release the hands holding the two ends of the hose, and the water in the bucket will flow out continuously until the water level in the bucket drops below the nozzle. This is because the rubber tube is filled with water, and the atmospheric pressure forces the water to flow into the rubber tube. Because the water outlet of the rubber pipe is lower than the water level in the bucket, a pressure difference is generated, and water flows out along the pipe. This is the siphon phenomenon.

Turn on the tap and fill the water tank hanging on the roof of the toilet. When the water level of the injected water is lower than the curved part of the upper end of the siphon, the siphon phenomenon will not occur because there is air in the pipe. When the injected water level is higher than the curved part above the water pipe, the water pipe is full of water, resulting in siphon phenomenon, and the water in the water tank automatically rushes out of the flushing sewer until the water level drops below the elbow inlet. Then the second water storage process began. After the water was full, the siphon phenomenon appeared again. As long as the water inflow is reasonably adjusted, the water tank can be flushed regularly and quantitatively.

9. Why does the sewer pipe go through the roof?

At present, kitchens and toilets in buildings should be equipped with coarse sewer pipes. This is because there is air in the empty pipe of the sewer, and the air takes up space. If the wastewater in the sewer can't squeeze out the air, it will be blocked at the upper end of the sewer, and the upper end of the sewer will pass through the roof, leaving a way out for the air in the sewer. When the wastewater flows downwards, the air will be squeezed upwards, and the air will flow into the atmosphere on the roof, so that the wastewater can flow downwards smoothly.

There are such examples in life. When we use a funnel to fill the bottle with oil, if the funnel presses on the bottle mouth and the air in the bottle cannot be discharged, the oil will stop in the funnel and will not leak into the bottle. When we lift the funnel from the bottle, there is a gap between the funnel and the bottle mouth, and the oil in the funnel will flow into the bottle smoothly. This is because the air in the bottle is discharged from the bottle between the bottle mouth and the funnel, and the oil that no longer blocks the funnel flows downward.

I suggest you look for the following books in libraries and bookstores first, and recommend the first two. If you find it difficult, just look at those on the last page. It's easier

1.& lt Chemistry and Society (original fifth edition) (specially recommended by the Chemical Society of chinese chemical society and the United States)

Authors: (USA) Lucy Pryde eubanks, edited by Catherine H. Middlecamp, translated by Duan, reviewed.

Publisher: Date of publication: August 2008

Environment, energy, daily life ... people are afraid of chemistry, but they can't do without it; How do we face chemistry correctly in a harmonious society? "Chemistry and Society" answers the chemical questions at your fingertips. Chemistry is an ancient and modern subject, which plays a key role in the development of human civilization. ...

2. Material science and material world-series of scientific and technological progress and modern civilization

Authors: Yang Ruicheng, Xu Ding, edited by Chen Kui.

Press: Chemical Industry Press. Date of publication: March 2005

Materials are the material basis for human survival and development. Based on the knowledge of materials science, this book introduces the relationship between materials and human civilization, the basic theoretical framework of materials science and engineering, then describes the general situation of materials family in detail, and finally looks forward to the future and development direction of materials. This book * * * ...

3. Chemistry and Life (He)

Author: He Editor

Publisher: Date of publication: February 2008

The book consists of five chapters, including chemistry and life, chemistry and environment, chemistry and energy, chemistry and materials, and green chemistry. The purpose is to enable students to acquire chemical knowledge related to life, guide students to know and understand chemical phenomena in life, pay attention to chemical problems in society and life, and improve their ability. ...

4. Chemical experiment and social life

Authors: Xu Peizhen and other editors.

Press: Nanjing University Press. Publication date: April 2008

This book is one of the natural science series textbooks for cultural quality education in colleges and universities. The book is divided into ten chapters, including basic operation, open experiment, selected experiment and design experiment of chemical experiment, involving chemistry and environment and environmental protection, chemistry and life and health, chemistry and food and diet balance, chemistry and life. ...

5. Chemistry and Society

Author: Meng Changgong, editor-in-chief

Press: Dalian University of Technology Press: 0 12008

This book is based on Chemistry and Modern Society written by the General Chemistry Teaching and Research Group of Dalian University of Technology in 2006, and has been further revised. Based on years of teaching practice, the editor tried to make it suitable for non-science students. In terms of content arrangement, this book is based on energy. ...

:search . book . Dangdang ./search . aspx？ Key= chemistry &; Category = 01.52&; Type =fl

There is an urgent need for practical examples in life to increase examples of beneficial friction.

1. There are many patterns on car tires and soles-(making the contact surface rougher);

2. In snowy days, the car is equipped with snow chains-(making the contact surface rougher);

3, snowy days, often sprinkle some ash on the road surface-(make the contact surface rougher);

4. Gymnasts always put some magnesium powder on their hands before going on the horizontal bar-(making the contact surface rougher);

5. Coat the belt with "oil" (or wax) during belt transmission (to make the contact surface rougher);

6. There are uneven patterns on the pedals and handlebars of bicycles-(making the contact surface rougher);

7. Speed bump on expressway-(making the contact surface rougher);

8, driving emergency braking, forcibly knead the handbrake-(increase the contact surface pressure);

9. When the conveyor belt slips, tighten the conveyor belt-(increase the contact surface pressure);

10, brake suddenly-(increase contact surface pressure);

1 1, writing force-(increasing the pressure on the contact surface);

12, clamp the workpiece with a vice-(increase the pressure on the contact surface);

13, when the train brakes, the wheels change from rolling to sliding-(from rolling to sliding);

14. After moving the large machine, before starting, remove the roller of the supporting point-(change rolling to sliding).

I hope I can help you. You can ask questions ~ ~ ~

I wish you progress in your studies and go up a storey still higher! (*^__^*)