Who can tell me some interesting chemistry experiments?

Can a glass rod be used instead of a match to light an alcohol lamp?

Experiment: put a small amount of potassium permanganate crystal on the mirror (or glass), drop 2 or 3 drops of concentrated sulfuric acid on potassium permanganate, dip it with a glass rod, and touch the wick of the alcohol lamp, and the alcohol lamp will light up immediately.

Drip ignition

Water can put out the fire, but can it be lit?

Experiment: Mix 5 grams of dry sucrose powder and 5 grams of potassium chlorate powder on an asbestos net, stir them evenly with a glass rod, pile them into hills, add 3 grams of sodium peroxide and drop them into water. Half a minute later, white smoke came out of the hill and soon burned.

An unbroken handkerchief.

The burnt handkerchief is actually intact?

Experiment: Soak the cotton handkerchief in the solution with the ratio of alcohol to water of 65,438+0: 65,438+0, then squeeze it gently, hold the two corners of the handkerchief with two crucible tongs, light it on the fire, and shake the handkerchief quickly to extinguish the flame when the flame decreases, and you will find that the handkerchief is still intact.

Principle: when burning, the flame of alcohol is outside the water layer, and the water absorbed in the fiber gap absorbs the heat of combustion and evaporates, so the temperature on the handkerchief can not reach the ignition point of the fiber, so the handkerchief can not be burned.

roll a snowball

Snowballs can burn?

Of course, it is not the real snowball that burns, but the calcium acetate separated from the calcium acetate solution in alcohol, like white snow, which is made into a ball and burned when it is ignited.

Experiment: Add 20 ml of water and 7 g of calcium acetate to make a saturated calcium acetate solution, add it to100 ml of 95% alcohol, and precipitate a snow-like solid under stirring.

An empty cup will smoke.

White smoke from an empty cup?

Experiment: Two clean and dry glasses, one with a few drops of concentrated hydrochloric acid and the other with a few drops of concentrated ammonia water, rotate the glasses to make the drops wet the glass wall, then cover the glass sheet, turn the glass with concentrated hydrochloric acid upside down on the glass with concentrated ammonia water, remove the glass sheet, and gradually you can see a glass full of white smoke.

1, small charcoal dance

Dear students, you must like chemistry very much, so you can do an interesting little experiment by yourself. The theme of this experiment is dancing with small charcoal. Take a test tube, fill it with 3-4g solid potassium nitrate, then fix it upright on an iron frame with an iron clip, and heat the test tube with an alcohol lamp. When the solid potassium nitrate gradually melts, take a piece of charcoal the size of a small bean, put it in a test tube and continue to heat it. After a while, you will see the small carbon block suddenly jumping up and down on the liquid level in the test tube, and then turn it over by itself, like dancing, giving off a fiery red light, which is very interesting. Please enjoy the beautiful dance of Little Charcoal. Can you answer why Xiao Tan dances?

answer

It turned out that when the small charcoal was just put into the test tube, the temperature of potassium nitrate in the test tube was low, so the small charcoal was still lying there. After heating the test tube, the temperature rises to make the small charcoal reach the ignition point. At this time, there is a fierce chemical reaction with potassium nitrate, which releases a lot of heat and makes the small charcoal burn and glow immediately. Because potassium nitrate decomposes at high temperature to release oxygen, this oxygen immediately reacts with small charcoal to generate carbon dioxide gas, which pushes small charcoal up at once. After the charcoal jumped up, it was out of contact with the potassium nitrate liquid below, the reaction was interrupted, and carbon dioxide gas was no longer produced. When the small charcoal falls back to potassium nitrate due to gravity, it reacts again and jumps up for the second time. In this cycle, Xiao Tan will keep jumping up and down.

2. Sugar turns into "black snow"

White sugar is a substance that people often eat. It is small white particles or powder, like snow in winter. However, I can turn it into "black snow" right away. If you don't believe me, please take a look at the following experiment. Put about 5g of white sugar into a 200ml beaker, and then drop a few drops of heated concentrated sulfuric acid. Suddenly, the sugar turned into a pile of fluffy "black snow", and the volume of the "black snow" gradually increased, even overflowing the beaker. Sugar suddenly became

Black Snow, that's interesting. Who knows the secret here?

answer

It turns out that there is a chemical reaction between sugar and concentrated sulfuric acid called dehydration. Concentrated sulfuric acid has a particularly eccentric hobby, that is, it especially wants to combine with water. It makes full use of the moisture in the air, even the moisture in other substances. As soon as we meet, it will take the water away. Sugar is a kind of carbohydrate (C 12H22O 1 1). When it meets concentrated sulfuric acid, the water in the sugar molecules is immediately taken away by it, and the rest is the poor sugar with carbon, which turns black. Concentrated sulfuric acid is not satisfied with taking water for its own use. It uses another skill-oxidation, which oxidizes part of the residual carbon in white sugar to generate carbon dioxide gas to escape.

C+2H2SO4=2H2O+2SO2+CO2

Due to the escape of carbon dioxide and sulfur dioxide gas produced after the reaction, the volume is getting bigger and bigger, and finally it becomes fluffy "black snow". In the "battle" of concentrated sulfuric acid against water, it is an exothermic process, so it gives a sneer and provides heat for the process of continuous oxidation of carbon by concentrated sulfuric acid.

3, no light bulb

An interesting chemistry performance in a middle school is going on enthusiastically, and one of the programs is particularly eye-catching. I saw a 200-watt light bulb hanging on a wooden pole, giving off dazzling white light. As far as brightness is concerned, ordinary electric lights are far behind. However, this light bulb has no wires, because it is a light bulb without electricity. Please think about it, where is the secret of this light bulb without electricity?

answer

It turns out that this bulb is filled with magnesium bars and concentrated sulfuric acid, and they have a fierce chemical reaction in the bulb, producing exothermic light. As we all know, concentrated sulfuric acid has strong oxidation ability, especially when it comes to some metals. Magnesium metal is particularly easy to be oxidized, so they are naturally "a match made in heaven". As soon as they meet, they will have a chemical reaction immediately:

Magnesium +2h2so4 (concentrated) = = magnesium sulfate +SO2+2h2o

In the process of reaction, a lot of heat is released, which makes the temperature in the bulb rise sharply and makes the magnesium bar reach the ignition point quickly. Under the condition of sufficient oxygen supply from concentrated sulfuric acid, magnesium bars burn more violently, just like flares.

4, water purification expert-alum

Speaking of alum, people are familiar with it, and some people call it alum, and the chemical name is potassium aluminum sulfate. But alum is not only used as a chemical raw material, but also a water purification expert! Once we went to the countryside for investigation, and when we were cooking lunch, we found that the water in the tank was too muddy to use. Just as we were worried, technician Zhang from the agricultural technology station came. Seeing that there was nothing we could do, he immediately took out a few pieces of alum, ground it into fine powder and sprinkled it in the jar. After a while, the water in the tank became clear and transparent. Although it has been several years, it is still fresh in my memory. However, I still don't understand why. Please explain it to me.

answer

It turned out that the mud dust in the water was "caught" by alum and sank to the bottom of the pool together. So, why can alum "catch" the mud and dust in running water? This should start with the turbidity of water itself. Tiny dirt and dust in water are not easy to settle down because of their light weight, and they "swim" in the water, making the water turbid. In addition, these tiny particles have another feature, that is, they like to pull some ions in the water to their side, or ionize some ions themselves, thus turning themselves into charged particles, which are often negatively charged. Because like charges repel and opposite charges attract, these negatively charged particles repel each other and cannot get together, so there is no chance to form larger particles and settle down. Alum, on the other hand, has a strange ability to make these inaccessible particles run together. When alum meets water, there will be a hydrolysis reaction with potassium sulfate as the supporting role and aluminum sulfate as the protagonist. Aluminum sulfate reacts with water to form a white flocculent precipitate-aluminum hydroxide. The generated positively charged aluminum hydroxide "hugs" each other as soon as it comes into contact with negatively charged sludge and dust particles. In this way, many particles gather together, and the particles get bigger and bigger, and finally they all sink to the bottom of the water, and the water becomes clear and transparent.

Simply put, it is the hydrolysis of aluminum ions.

5. Boiled eggs with lime

The school building of Nanjing primary school is going to be repaired again, and the workers and teachers are arguing like boiling water. HuiQing and Yan Li stood watching curiously, chatting. Hui Qing said, "Look at this heat, you can definitely cook the eggs." Li Yan said: "Impossible." To find out, they took an egg from home and buried it in a pile of steaming lime. After a while, the egg exploded with a bang. They are even more puzzled when they see this situation. They thought about it and didn't understand what was going on. Who can explain it to them?

answer

There is a simple reason. The chemical name of quicklime is calcium oxide, which becomes hydrated lime after adding water, and the chemical name is calcium hydroxide, commonly known as white ash. The process of converting quicklime into hydrated lime is called "digestion", which is an exothermic reaction:

6. Unstable sanitary ball

Speaking of fitness balls, everyone must be familiar with them. They are often used to kill moths in suitcases. However, what happens when you put it in an aqueous solution containing acetic acid and baking soda? At first, it slept at the bottom of the cup. After a while, it became restless, but it jumped up and down in the water like crazy. Who knows why?

answer

After this chemical reaction, the easily generated carbon dioxide gas becomes tiny bubbles attached to the bottom or wall of the cup, and the whole body of the sanitary ball is covered by these bubbles. Carbon dioxide is lighter than water, so it will rise to the surface. Once the bubbles on the sanitary ball reach a certain level, they will rise straight like a drowning person pulling a lifebuoy. When the sanitary ball rises to the water surface, the small bubbles attached to the sanitary ball burst due to the decrease of pressure, and the sanitary ball recovered its original proportion and lost its "life buoy", so it sank back to the bottom of the cup, stuck enough small bubbles and floated up again. In this way, the sanitary ball will run around.

7. The origin of "bhc" powder name.

An insect pest occurred in a wheat field in the suburbs. In order to resist disasters and kill insects, farmers sprayed a chemical pesticide powder called "bhc". At this time, clever classmate A solemnly asked classmate B: "Why do you say this pesticide is called' BHC' powder?" "I don't know yet, because when this pesticide was invented, scientists experimented 666 times." Student B answered confidently. A classmate retorted, "What you said is wrong. It is said that this pesticide is made of 666 kinds of drugs, so it is called' BHC' powder. The two students are arguing with each other. ...

Please comment. Which of them is right? Why?

answer

Neither of the two students is right. This insecticide is produced by the reaction of a chemical called benzene with chlorine under ultraviolet radiation.

C6H6 13C 12 = C6H6Cl6

As can be seen from the molecular formula of the generated BHC powder, its molecule consists of six carbon atoms, six hydrogen atoms and six chlorine atoms, so it is called BHC powder.

8. The magical use of ammonium chloride fireproof cloth

Dear students, I soaked an ordinary cotton cloth in the saturated solution of ammonium chloride. After a while, I took it out to dry and made a fireproof cloth. This chemically treated cloth, if ignited with a match, will not ignite and will emit white smoke. Please tell me, what is the reason?

answer

It turns out that the surface of this chemically treated cotton cloth (fireproof cloth) is covered with crystal particles of ammonium chloride, which has a strange temper, that is, it is particularly afraid of heat. When heated, it will undergo chemical changes and decompose two kinds of non-combustible gases, one is ammonia and the other is hydrogen chloride.

NH4Cl-& gt； NH3 (gas) +HC 1 (gas)

These two gases isolate cotton cloth from air, and cotton cloth can't burn without oxygen. When these two gases protect cotton cloth from fire, they meet in the air and recombine into small crystals of ammonium chloride, which are scattered in the air like white smoke. In fact, ammonium chloride is a good expert in fire prevention. The stage scenery of the theater and the wood on the ship are often treated with ammonium chloride to achieve the purpose of fire prevention.

9. The ups and downs of eggs

Fill a big beaker with dilute hydrochloric acid solution, then put a fresh egg in the beaker, and it will immediately bottom out. After a while, the egg rises to the liquid level again, and then sinks to the bottom of the cup. After a while, the egg floats to the liquid level again, and so on many times. Please analyze it. What is the reason?

answer

Because the main component of egg shell is calcium carbonate, it will react with dilute hydrochloric acid to generate calcium chloride and carbon dioxide gas.

Cac0312hc1= CAC121c02 (gas) 1H20.

The bubbles formed by carbon dioxide gas are tightly attached to the eggshell, and the buoyancy generated makes the eggs float. When the egg rises to the liquid level, the pressure on the bubbles is less, some bubbles burst, and carbon dioxide gas diffuses into the air, thus reducing the buoyancy and the egg begins to sink again. When it sinks to the bottom of the cup, the dilute acid constantly reacts with the eggshell, constantly producing carbon dioxide bubbles, thus making the egg float again. In this way, the egg moves up and down repeatedly. Finally, when the eggshell comes into contact with hydrochloric acid, the reaction stops and the up-and-down movement of the egg stops. But at this time, because the liquid in the cup contains a lot of calcium chloride and residual hydrochloric acid, the specific gravity of the liquid is greater than that of the egg, so the egg finally floats on the liquid.

10, not "glass cutter" in glass cutter.

Dear students, do you want to carve a beautiful pattern on a piece of glass? You can use glass cutter's "glass cutter" to carve this pattern. The method is simple. Coat the glass with a thin layer of molten paraffin. After coagulation, use the needle tip to carve the pattern you need on the paraffin. In addition, take a lead evaporating dish, put calcium fluoride and sulfuric acid in the evaporating dish, put a circle of rubber on the edge of the evaporating dish, then put the waxed picture face down on the evaporating dish, heat it slightly, and wipe off the paraffin on the surface with gasoline. At this time, beautiful patterns were carved on the glass. You must find it interesting, so please think about it. This is not glass cutter's "glass cutter". What is it? Why can it carve patterns on glass?

answer

This glass cutter is not glass cutter, but hydrofluoric acid. Because calcium fluoride reacts with sulfuric acid to generate hydrogen fluoride and calcium sulfate, hydrogen fluoride gas volatilizes from the solution into the glass and dissolves in the water above the glass to form hydrofluoric acid, which does not react with paraffin, but has a very strange chemical temper, that is, it reacts with silicon dioxide, the main raw material for forming glass, and generates water and fluoride gas after the reaction. This kind of acid that can "eat" glass is not called "glass cutter" in glass cutter. In this way, any glass surface that is not covered and protected by paraffin (that is, the pattern part) is "eaten" by this acid, and the pattern on the glass appears after removing paraffin. The reaction is as follows:

4HF ten Si02 = 2H20 ten SiF4 (gas)

1 1. The glass rod ignited the ice.

Glass rods can ignite ice cubes. You must think this is a joke. However, what I said is completely true. It is surprising that ice can burn. What is even more surprising is that in the absence of matches and lighters, as long as a glass rod is gently used, the ice will burn immediately and will not go out for a long time. You can do an experiment if you are interested. First, pour 1-2 small potassium permanganate into a small dish, gently grind it into powder, then drop a few drops of concentrated sulfuric acid and stir it evenly with a glass rod. The glass rod immersed in this mixture is an invisible small torch, which can ignite alcohol lamps or ice cubes. However, put a small piece of calcium carbide on the ice in advance, so that the ice will burn as long as it is gently touched with a glass rod. Please answer after the experiment.

answer

There is a simple reason. Calcium carbide (chemically called calcium carbide) on the ice surface reacts with a small amount of water on the ice surface, and the calcium carbide gas (chemically called acetylene) produced by this reaction is flammable. Because concentrated sulfuric acid and potassium permanganate are both strong oxidants, they are enough to oxidize calcium carbide gas, reach the ignition point immediately, and make calcium carbide gas burn. In addition, because the reaction between water and calcium carbide is exothermic, the combustion of calcium carbide gas is exothermic, and more and more water is melted into ice cubes, so the calcium carbide reaction is more and more rapid, and the calcium carbide gas is more and more, and the fire is more and more prosperous.

12, learn about copper in silver

High purity silver wire is needed in the production process of the factory. One day, the supplier bought a batch of silver wires from other places. A technician looked at the silver wire and said, "This silver wire is impure and doped with copper, so it can't be used." But some people disagree with him that there is no copper in it. Who is right about these two statements? Please help readers to identify it by chemical methods to see if there is copper in this batch of silver wires.

answer

First, take a small amount of silver wire and dissolve it in concentrated nitric acid. Then take this small amount of solution and add it to the excess hydrochloric acid. If white precipitate is generated at this time, filter out the white precipitate. Then a large amount of ammonia water is added to the filtrate. If dark blue cuprammonia complex ions are generated, the existence of copper is proved. On the other hand, if there is no dark blue copper-ammonia complex ion, it is proved that there is no copper.

13, mysterious picture

In an interesting chemical performance, the performer performed a mysterious picture. He hung a piece of white paper on the wall, then picked up the sprayer and sprayed a colorless and transparent liquid on this piece of white paper. In a blink of an eye, a beautiful picture was presented to the audience. In the dark blue waves, there is a big red-brown ship. His performance surprised the audience! Obviously it is a blank sheet of paper, why did you suddenly spray a beautiful picture? Dear readers, do you know the secret of this performer's painting?

answer

This is an ordinary chemical reaction. The white paper hanging on the wall has been pretreated by the performers. On this piece of white paper, he first drew a surging sea with yellowish potassium ferrocyanide solution, and then drew a huge ship in the sea with colorless and transparent potassium thiocyanate solution. After drying, there is no trace on the white paper. It turns out that the sprayer is filled with ferric chloride solution. When ferric chloride solution is sprayed on white paper, two chemical reactions occur on white paper at the same time. One is that ferric trichloride reacts with potassium ferrocyanide to generate iron ferrocyanide (blue), and the other is that ferric trichloride reacts with potassium thiocyanate to generate iron thiocyanate (red-brown). In this way, the blue sea and the red-brown boat were "sprayed".

14, blow out the burning candle.

Ordinary candles, when burned, can be blown out in one breath. However, there is a special kind of candle. When you need to light it, just blow it. Please watch the magician's performance. The magician showed it to the audience on purpose, convincing them that it was an ordinary candle. Then he put the candle on the wax table, blew a breath into the wax heart, and the candle burned. After watching the magician's performance, can you solve the mystery of burning when the candle is blown out?

answer

It turned out that the magician loosened the candle core before the performance and dropped some carbon disulfide solution dissolved with white phosphorus. Because carbon disulfide liquid is a volatile substance, the magician blows for a long time to further accelerate its volatilization speed. When carbon disulfide is completely volatilized, tiny white phosphorus particles are left on the wick, and the white phosphorus reacts with oxygen in the air to generate heat. When the temperature rises to 35℃, the white phosphorus will burn by itself, and then the original extinguished wick will be led out again. This burning phenomenon caused by the oxidation of white phosphorus in the air often occurs in nature, which is what people call "skyfire" or "ghost fire".

15, tea-ink-tea

On Sunday, Xiaoming and his father watched a magic show at the Workers' Cultural Palace. One of the programs is: tea turns into ink, and ink turns into tea. The magician on the stage has less than a cup of black tea in his hand. He stirred it with a glass rod and shouted, "Change!" At this point, the tea leaves immediately turned into blue ink. Then, the magician stirred the other end of the glass rod in the ink bottle and shouted "Change". Sure enough, the blue ink just turned into the original tea. What a wonderful performance! Xiao Ming is full of praise. But he couldn't figure out how it changed, so he asked readers to help him figure out the reasons for the change.

answer

This is a very interesting chemical reaction. Originally, one end of the glass rod was soaked in copperas (chemical name is ferrous sulfate) powder in advance, and the other end was soaked in oxalic acid crystal powder. Because tea contains a lot of tannic acid, when tannic acid meets ferrous ions in copperas, it immediately generates ferrous tannic acid, which is unstable in nature and is quickly oxidized to form a complex of iron tannic acid, which is blue-black, thus turning tea into "ink". Oxalic acid is reducible, which reduces ferric ions to ferrous ions, so the blue-black color of the solution disappears again and the color of tea reappears. This phenomenon is also often encountered in people's lives. When you cut the immature fruit with a knife, you often see blue on the edge of the fruit. Some people think it was caused by an unclean knife. In fact, this situation is the same as the above-mentioned tea turning into ink, which is the result of a chemical reaction between iron on the knife and tannic acid on the fruit.

16, Underwater Park

Curious little students performed a wonderful little program-underwater garden at the party celebrating the International Children's Day on June 1st. The performance has begun. Under the gaze of hundreds of pairs of eager and curious eyes, Xiao curiously put several small pieces of different colors as big as rice grains into a glass jar filled with colorless and transparent aqueous solution. Soon, all kinds of branches appeared in the glass jar, stretching criss-crossing, green leaves became more and more lush, and bright flowers were in full bloom! A deep-rooted underwater garden is presented to the audience. Suddenly applause thundered, and everyone congratulated Xiao Curious on his wonderful performance. After a while, he pointed to the underwater garden to explain. Readers, do you know the secret of Xiao Curious to build this underwater park?

answer

The colorless and transparent liquid originally contained in the glass jar is not water, but an aqueous solution called sodium silicate (people call it water glass). Small particles of various colors are small crystals of several water-soluble colored salts, such as ammonium dichloride, copper sulfate, ferric sulfate, ferrous sulfate, zinc sulfate and nickel sulfate. These small crystals react with sodium silicate to form purple sub-rhombic silicate, blue copper silicate, reddish brown iron silicate, light green ferrous silicate, dark green nickel silicate and white zinc silicate. The reaction between these small crystals and sodium silicate is a very unique and interesting chemical reaction. When these small crystals are put into a glass jar, a water-insoluble silicate film is immediately formed on their surfaces, and this colored film covers the surfaces of the crystals. However, this kind of membrane has a strange temper, which only allows water molecules to pass through and shuts out molecules of other substances. When water molecules enter this film, small crystals are dissolved by water, and high-concentration salt solution is generated in the film, which generates high pressure and makes the film expand until. The colored salt solution in the membrane flows out and reacts with sodium silicate to form a new membrane. Water seeps into the film again, and the film bulges and breaks again ... 6 Every time this cycle is carried out, the branches and leaves of the flower grow a new section. In this way, it only takes a moment to form an underwater garden with lush foliage and blooming flowers.

17, clear water-soybean milk-clear water

On Sunday, Lily, a little chemistry fan, performed a little magic trick for the children in the same hospital. The content is that clear water has become "soybean milk" and "soybean milk" has become clear water. I saw Lily holding a colorless and transparent bottle with half a bottle of water in it, and then covering it with a rubber stopper. Then he said to the small audience, "I can turn this bottle of clear water into soybean milk" and then turn soybean milk into clear water. "Say that finish, I saw her gently shake the bottle and say" change ".The clear water in the bottle immediately turned into milky" soybean milk ". Lily told her little friend: "Please note that this soybean milk can only be seen, not drunk!" " "Then she called" change "and saw that she shook the bottle a few times. Sure enough, the white" soybean milk "turned into clear water again. The onlookers are puzzled. Please guess, how did this little chemistry fan's tricks change?

answer

It turns out that Lily put a small amount of alum (chemical name is potassium aluminum sulfate) in the clear water in the bottle in advance. Because alum is soluble in water, the bottle is still colorless and transparent water. When she called "change" for the first time, a small amount of sodium hydroxide (chemical name is sodium hydroxide) stuck in the concave of the rubber stopper was dissolved in clear water because of gently shaking the bottle. At this time, caustic soda reacts with alum to produce milky precipitated aluminum hydroxide, and clear water becomes milky solution, which looks like soybean milk. The reaction is as follows:

2ka1(s04) 2+6nahoh = 3na2s04tenk2s04ten2al (oh) 3 (milky white)

When Lily called for change for the second time, she shook the bottle a few times. At this time, the liquid in the bottle dissolves all the caustic soda tablets in the concave part of the rubber stopper, and the caustic soda and aluminum hydroxide continue to react chemically to generate colorless sodium metaaluminate soluble in water, so that the white "soybean milk" becomes clear again. The reaction is as follows:

a 1(OH)3 Ten NaOH = naal 02 Ten 2h2o

Lily's trick proved that aluminum has extremely special chemical properties-metallic and nonmetallic.

18, burning paper with water

At the science and technology performance held in the Children's Palace, a young classmate performed chemical magic, which caused a sensation among the small audience. I saw a blank sheet of paper in his hand and waved it at the audience twice, indicating that it was an ordinary blank sheet of paper. However, he stacked the white paper layer by layer and said to the audience, "I can light this white paper with water ..." His voice did not fall, and a brave child in the audience said, "Impossible, water can put out the fire, how can you light the paper with water?" "I can't say it. Water can't burn, let alone paper. " "Exactly, fire and water are incompatible and always opposed!" The little students are talking noisily. At this time, another classmate asked, "The water you use is not ordinary water, it may be something else!" " "As he spoke, he took out his glass, poured a glass of water, and then went to the stage to let the performer use his glass of water. The performer accepted his request and gently dipped the white paper in his hand into a glass of water. The white paper is really hot. "trance! Water can really ignite paper! "Few viewers are talking about it. Dear readers, when you know that water can light paper, you can also feel the existence of "God". So where is this "God"?

answer

In fact, it is not mysterious, it is nothing more than a phenomenon produced by a very common chemical reaction. It turned out that a small piece of metal sodium had been stuck on the white paper that the performer had held in advance. Because sodium metal is white, it is not easy for the audience under the stage to see it. He folded the white paper several times and wrapped the sodium metal in the middle to prevent it from being oxidized in the air. Sodium metal has very active chemical properties and can react violently with water to generate sodium hydroxide and hydrogen. At the same time, this reaction releases a lot of heat, which makes the temperature of paper rise rapidly and reach the ignition point immediately. This reaction also releases hydrogen, and when hydrogen burns, the paper burns with it. Not only sodium metal has this property, but also potassium metal and metal hammer have this chemical property.

19, beautiful night sky

On the night of Mid-Autumn Festival, the night sky is beautiful. The blue sky is full of stars, just like velvet covered with pearls and jewels. There is also a bright moon hanging in the blue sky, floating, floating, as if Chang 'e was going out of the moon palace. Dancing on floating clouds ... It turns out that the beauty of the Mid-Autumn night sky can be born in a magician's test tube. Dear readers, do you also want to enjoy this beautiful night scene? Then use your skillful hands to activate your brain full of chemical knowledge and design it carefully!

answer

Add a few milliliters of anhydrous alcohol (95% alcohol is enough) to the test tube, then slowly drop the same amount of concentrated sulfuric acid, lift a piece of dark blue glossy paper on the back of the test tube, shake the test tube several times to mix the concentrated sulfuric acid and alcohol evenly, turn off the lights, and then slowly put some potassium permanganate particles into the test tube. After a while, you can enjoy this "liquid starlight". It turns out that a series of chemical reactions are taking place in the test tube. Purple potassium permanganate is a strong oxidant. "Alum and concentrated sulfuric acid, release oxygen, but also release a lot of heat. At this time, the alcohol around the potassium permanganate particles quickly reached the ignition point, producing dazzling sparks. Due to thermal convection, these flashing flames