What are the interesting chemical experiments in life?

What are the phenomena of interesting chemical experiments in life

Hello, there are many phenomena in interesting chemical experiments in life. Here are some examples.

1. Breathe "fairy breath":

Experimental supplies: glass tube with pointed mouth, alcohol lamp, colored plastic tube and cotton wool.

gasoline, soap and glycerin.

experimental principle: gasoline vapor can be ignited. When gasoline is mixed with air, it will burn violently and make an explosion in case of fire.

Experimental operation: A colored plastic tube is coated on a 2 cm long glass tube with a pointed mouth, and a cotton ball saturated with gasoline is placed in the tube. Point the tip tube at the flame of the alcohol lamp and blow into the other end of the glass tube. When gas comes out of the nozzle tube, it burns when it meets fire. Leave the flame and continue to burn. If the blowing force to the glass tube is slightly larger, the flame can be 4 ~ 5 cm away from the sharp mouth and present a bright blue flame, which is very beautiful.

at this time, dip the tip of the glass tube into soap solution with a little glycerin dripping. After taking it out, blow air to the other end of the glass tube. When soap bubbles appear in the air in series, it is very interesting to use burning alcohol cotton balls to light one soap bubble after another, and then a series of slight explosions and fireballs are emitted.

2. Fire extinguishing painting:

Experimental supplies:

1ml beaker, writing brush, brush, glass rod, glass plate and color picture.

concentrated solution of borax, saturated solution of alum, gunpowder cotton, acetone and aluminum powder.

experimental principle:

after the picture is treated with borax and alum solution successively, there is a protective layer that is not easy to burn on the picture. Powder cotton burns quickly, so the picture won't burn out.

Experimental operation:

Take a color picture, coat it with a layer of borax solution with a brush, dry it and coat it with a layer of alum solution, and then dry it for later use.

put gunpowder cotton in a small beaker, add acetone and aluminum powder, and mix well. Then brush the acetone thick liquid of gunpowder cotton on the glass plate, and the brush area is slightly larger than the picture. Brush 3 ~ 4 times repeatedly, remove it after drying and stick it on the picture. At this time, the gunpowder cotton was ignited with a match. When the gunpowder cotton was quickly burned out, a beautiful picture appeared in front of us.

3. Fire that can't burn paper:

Experimental supplies:

evaporating dish, glass rod, tweezers, paper,? Carbon disulfide, carbon tetrachloride.

experimental principle:

carbon disulfide is a flammable liquid, but carbon tetrachloride can't burn. Carbon disulfide burns to produce carbon dioxide and sulfur dioxide, and emits heat at the same time.

Because there is carbon tetrachloride in it, carbon tetrachloride takes away a lot of heat when it volatilizes in large quantities, so the temperature of the flame is reduced and the ignition point of the paper cannot be reached.

experimental operation:

pour 6 ml of carbon disulfide and 16 ml of carbon tetrachloride into the evaporating dish and stir well. Light blue flame can be seen after being ignited by fire. At this time, a piece of ordinary paper was placed on the flame with tweezers, but the paper could not burn. What are the interesting chemical phenomena in life?

Duck with automatic hair growth:

Cut the aluminum skin into a duck shape (rabbit, cat, mouse ... whatever), dip a cotton swab into the HgNO3 solution and apply it to the aluminum skin, and wipe the HgNO3 on the aluminum skin dry after a few minutes. Then you can see that the aluminum duck automatically grows white hair!

experimental principle: aluminum is an active metal, but there is a dense oxide film on the surface of aluminum, which prevents the reaction between aluminum and air. After HgNO3 solution was coated, the dense oxide film was destroyed and Al-Hg alloy was formed, which made it impossible to form a dense oxide film on Al surface. Al can continuously react with oxygen in the air to produce white Al2O3.

note: HgNO3 is a highly toxic compound, so pay attention to the protective measures during the experiment!

build a "garden in water"

dissolve sodium silicate (Na2SiO3) in water to make water glass with 4% solute mass fraction, and gently add salt grains, such as chlorides of cobalt, iron, copper, nickel and lead, sulfates of aluminum, iron, copper and nickel, and nitrates of cobalt, iron, copper and nickel into the water glass (be careful not to shake them).

experiment: put a small amount of potassium permanganate crystal on a watch glasses (or a glass sheet), drop 2 or 3 drops of concentrated sulfuric acid on the potassium permanganate, dip it with a glass rod, and then touch the wick of the alcohol lamp, and the alcohol lamp will be lit immediately.

Protein marks

Take an egg, wash off the oil stains on the surface and dry it. Dip a brush into acetic acid and write on the eggshell. After the acetic acid evaporates, cook the eggs in dilute copper sulfate solution, and peel off the eggshell after the eggs are cooled, leaving clear blue or purple handwriting on the egg white, but leaving no trace on the shell.

This is because acetic acid can dissolve a small amount of protein in eggshells. Egg white is a globulin composed of amino acids, which hydrolyzes under weak acidic conditions to produce peptides and other substances. The peptide bonds in these substances complexed with Cu2+, showing blue or purple color

Water-fire compatibility

Put a dozen potassium chlorate crystals into the bottom of a glass, and then put a few small yellow phosphorus particles into the potassium chlorate crystals with tweezers. Then use a glass pipette to absorb a little concentrated sulfuric acid and transfer it into the mixture of potassium chlorate and yellow phosphorus, and then there will be fire in the water. If there is fire in the water, isn't it "compatible with water and fire"?

where is the secret? Put potassium chlorate in water, which is an oxygen-containing compound; Then put in yellow phosphorus, which is extremely flammable. Because it is isolated from oxygen in the air in water, it does not spontaneously ignite. However, when concentrated sulfuric acid is added, the concentrated sulfuric acid reacts with potassium chlorate to generate chlorate, which is unstable and releases oxygen. Oxygen reacts with yellow phosphorus and burns. This reaction is particularly violent, so it can also be carried out in water, so that fire and water are in the same cup. Phosphorus is oxidized to produce phosphorus pentoxide, which reacts with water to produce phosphoric acid

blowing to make a fire

Experimental principle: Sodium peroxide can react with carbon dioxide to produce oxygen and give off a lot of heat, which makes cotton catch fire.

experimental articles: evaporating dish, glass rod, tweezers, slender glass tube. Na2O2, absorbent cotton.

experimental steps

1. spread a small amount of Na2O2 powder on a thin layer of absorbent cotton and gently press it with a glass rod to make Na2O2 enter the absorbent cotton.

2. gently roll the absorbent cotton with Na2O2 with tweezers and put it in an evaporating dish.

3. Blow the absorbent cotton slowly with a slender glass tube. Observe the phenomena What are the interesting physical and chemical experiments in life

Interesting chemical phenomena in life

1. Dancing with small charcoal

Dear students, you must like chemistry very much, so do an interesting little experiment by yourself. The title 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 into a test tube, and continue to heat it. After a while, you will see the small charcoal block suddenly jump up and down on the liquid surface in the test tube, and then turn itself over, like dancing, and emit hot red light, which is very interesting. Please enjoy the beautiful dance of Little Charcoal. Can you answer why Xiao Charcoal dances?

Answer

It turns out that when the small charcoal was just put into the test tube, the temperature of potassium nitrate in the test tube was low, and it could not make the charcoal burn, so the small charcoal was still lying there. After heating the test tube, the temperature rises, so that the small charcoal reaches the ignition point. At this time, it has a fierce chemical reaction with potassium nitrate and gives off a lot of heat, which makes the small charcoal burn and glow immediately. Because potassium nitrate decomposes at high temperature and releases oxygen, this oxygen immediately reacts with small charcoal to generate carbon dioxide gas, which suddenly pushes the small charcoal up. After the charcoal jumped up, it was out of contact with the potassium nitrate liquid below, and the reaction was interrupted, so the carbon dioxide gas no longer occurred. When the small charcoal fell back to the potassium nitrate due to gravity, it reacted again and jumped up for the second time. This kind of circle goes back and forth, and the small charcoal keeps jumping up and down.

2. White sugar turns into "black snow"

White sugar is a substance that people often eat. It is small white particles or powdery, like snow in winter. However, I can turn it into "black snow" immediately. If you don't believe me, please take a look at the following experiment. Put about 5g of white sugar into a 2ml beaker, and then drop a few drops of heated concentrated sulfuric acid. Suddenly, the white sugar becomes a pile of fluffy "black snow", and the volume of the "black snow" gradually increases and even overflows the beaker. Sugar suddenly turned into

' black snow', which is really interesting. Who knows the secret here?

Answer

It turns out that sugar and concentrated sulfuric acid have a chemical reaction called dehydration. Concentrated sulfuric acid has a particularly eccentric hobby, that is, it has a particularly strong desire to combine with water. It makes full use of the moisture in the air, even the moisture in other substances. As soon as it meets, it has to take the water away. Sugar is a kind of carbohydrate (c12h22o11). When it meets concentrated sulfuric acid, the water in the sugar molecule is immediately taken away by it, leaving the poor sugar with charcoal and turning black. After the concentrated sulfuric acid took the water for its own use, it was not satisfied. It used another skill-oxidation, which oxidized part of the carbon left in the white sugar and generated carbon dioxide gas to escape.

c+2h2so4=2h2o+2so2+co2

Because the carbon dioxide and sulfur dioxide gas generated after the reaction ran out, the volume became larger and larger, and finally it became fluffy "black snow". In the "battle" of concentrated sulfuric acid for water, it is an exothermic process, so it makes a sneering noise and provides heat for the process of continuous oxidation of carbon by concentrated sulfuric acid.

3. Light bulb without electricity

A fun chemical performance meeting in a middle school is going on enthusiastically, and one of the programs is particularly eye-catching. I saw a light bulb of about 2 watts hanging from a wooden pole, which emits dazzling white light. As far as brightness is concerned, ordinary light bulbs are far behind it. However, this light bulb does not have any 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 light bulb is filled with magnesium bars and concentrated sulfuric acid, and they have a fierce chemical reaction in the light bulb, causing exothermic luminescence. As we all know, concentrated sulfuric acid has strong oxidizing ability, especially when it meets some metals. Metal magnesium is particularly easy to be oxidized, so they are naturally "suitable for each other". As soon as they meet each other, they will immediately undergo a chemical reaction:

Mg+2H2SO4 (concentrated) = MgSO4+SO2+2H2

During the reaction, a lot of heat is released, which makes the temperature in the light bulb rise sharply, and quickly makes the magnesium bar reach the ignition point.

4. Alum

Speaking of alum, people are familiar with it. Some people call it alum, and its chemical name is aluminum potassium sulfate. However, alum is not only used as a chemical raw material, but also an expert in water purification! Once, when we went to the countryside for investigation and study, when we were cooking lunch, we found that the water in the tank was too muddy to use. While we were worried about it, technician Zhang from the agricultural technology station came. Seeing that we had no choice, he immediately took out a few pieces of alum, ground it into fine powder and sprinkled it in the tank. After a while, the water in the tank became clear and transparent. Although it has been a few years, it is still fresh in my memory. However, I still don't understand what the reason is. Please explain it to me.

Answer

It turns out that the mud and dust in the water were "caught" by alum and sank to the bottom of the tank together. So, why can alum "catch" the mud and dust in living water? This starts with the turbidity of water itself. The extremely small dirt and dust in the water are not easy to settle down because of their light weight, and they "wander" in the water, making the water turbid. In addition, these tiny particles also have a feature, that is, they like to pull some ions from the water to their side, or ionize some ions themselves, thus turning themselves into charged particles, which are often negatively charged. Because charges of the same sex repel and charges of the opposite sex attract, these negatively charged particles repel each other and cannot get together, so they have no chance to form larger particles and settle down. Alum, on the other hand, has a strange ability to make these particles that can't get close to each other run together. As soon as alum meets water, it will undergo a hydrolysis reaction in which potassium sulfate is a supporting role and aluminum sulfate is a leading role. Aluminum sulfate reacts with water to form a white flocculent precipitate-aluminum hydroxide. The generated aluminum hydroxide with positive charge "hugs" each other as soon as it touches the mud and dust particles with negative charge. In this way, many particles gather together, the particles get bigger and bigger, and finally both sink to the bottom of the water, and the water becomes clear and transparent.

Simply put, it's aluminum ion hydrolysis

5. Boiled eggs with lime

The school building of Nanjing Primary School needs to be repaired again, and the noise of the workers' masters is like boiling a pot. Hui Qing and Yan Li stood watching curiously and talking. Hui Qing said, "Look at this heat, it will definitely cook the eggs." Yanli said, "It's impossible." In order to find out, they took an egg from home and buried it in a steaming pile of lime. After a while, there was a bang and the egg exploded. When they saw this situation, they were even more puzzled. They thought about it and didn't understand what was going on. Who can explain it to them?

the answer

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

6. Unstable sanitary ball

Speaking of sanitary ball, everyone must be familiar with it and often use it 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, but after a while, it became restless, but it jumped up and down in the water as if it were insane. Who knows why?

Answer

The carbon dioxide gas that is easily generated by this chemical reaction becomes tiny bubbles that adhere to the bottom or wall of the cup, and the whole body of the sanitary ball is covered with these bubbles. Carbon dioxide is lighter than water, so it will rise to the surface. Once the bubble stuck by the sanitary ball reaches a certain level, it will rise straight like a drowning person pulling a lifebuoy. When the sanitary ball rises to the surface of the water, due to the reduction of the pressure, the small bubbles attached to the sanitary ball burst, and the sanitary ball regained its original proportion, losing its "life buoy".