Experiments with dry fuel. Study "Pharaoh Serpents" in chemistry chemistry project (Grade 9) on the topic. Necessary Precautions

Every home is full of substances that can be used as reagents for experiments. Of course, not everyone will be able to carry out complex chemical experiments at home, but even a novice chemist can carry out several interesting reactions.

pharaoh snakes

Pharaoh snakes are not reptiles, as one might think, but a group chemical reactions, during which a porous mass resembling a snake is formed from a very small volume of the reagent. Some of these processes are feasible only in the laboratory due to the toxicity of the reagents or their lack of free sale. However, several varieties of "snakes" can be obtained at home.

The most accessible version of this experience is the baking soda and sugar snake. To get it, we need:

• river sand;
• a teaspoon of sugar, crushed into powder;
• a quarter of the same spoon of baking soda;
• a little ethyl alcohol (96% will be enough);
• plate;
• matches or lighter.

Pour river sand on a plate and soak it with alcohol. Make a depression at the top of the mound. Put a mixture of sugar and soda into it. Set fire to the hill. The alcohol with which it is soaked will catch fire. A few minutes later, when it is almost burnt out, a black, writhing mass, very reminiscent of a viper, will crawl from the sandy cone.

Experience has a simple justification. Sugar and alcohol burn, and baking soda decomposes when heated. All these processes are accompanied by the release of carbon dioxide and water vapor. They give porosity to the burning mass. The "snake" itself consists of a mixture of sodium carbonate, formed during the decomposition of soda, with coal, obtained by burning powdered sugar:

Another "reptile" can be obtained from dry fuel and calcium gluconate. The latter is a pill that is sold in any pharmacy without a prescription and is quite inexpensive.

Place calcium gluconate on a tablet of dry fuel, set it on fire. A gray snake will crawl out of the pill. In this experiment, you can do without fuel. It is enough to bring a tablet of calcium gluconate to the flame.

When heated, the drug decomposes into carbon dioxide, water, calcium oxide, coal. The last two substances form the basis of the snake, and carbon dioxide and vaporous water make it porous and make it crawl:

Volcano

Volcanoes are another kind of spectacular reactions. In chemistry class, you may have seen ammonium dichromate volcano. However, the same chemical experiment can be repeated at home.

You will need:

• plate;
• plasticine or clay;
• acetic acid (vinegar);
• dishwashing liquid;
• food coloring, fukortsin from the first aid kit or beet juice.

From plasticine, fashion a volcano cone, hollow inside, but having a dense bottom below that does not let water through. "Charge" your volcano. To do this, pour a tablespoon of soda into its mouth, pour in the same amount of dishwashing liquid and add a few drops of dye. Then pour in the same quarter cup of vinegar.

A brightly colored foam will crawl out of the vent of the volcano, consisting of carbon dioxide and soda residues:

As you can see, even on the basis of such available substances as soda and vinegar, interesting chemical experiments can be carried out at home.

A large black snake grows out of a hill of sugar and soda

Complexity:

Danger:

Do this experiment at home

Reagents

Security

Put on safety goggles before starting the experiment.

Do the experiment on a tray.

Keep a container of water nearby during the experiment.

Place the burner on the cork stand. Do not touch the burner immediately after completing the experiment - wait until it cools down.

General safety rules

• Avoid getting chemicals in your eyes or mouth.
• Do not allow people without goggles, as well as small children and animals, to the experiment site.
• Keep the experimental kit out of the reach of children under 12 years of age.
• Wash or clean all equipment and accessories after use.
• Make sure all reagent containers are tightly closed and properly stored after use.
• Make sure all disposable containers are properly disposed of.
• Use only the equipment and reagents supplied in the kit or recommended in the current instructions.
• If you have used a food container or experiment utensils, discard them immediately. They are no longer suitable for food storage.

First Aid Information

• If reagents come into contact with eyes, rinse eyes thoroughly with water, keeping eyes open if necessary. Seek immediate medical attention.
• If swallowed, rinse mouth with water, drink some clean water. Don't induce vomiting. Seek immediate medical attention.
• In case of inhalation of reagents, remove the victim to fresh air.
• In case of skin contact or burns, flush the affected area with plenty of water for 10 minutes or longer.
• If in doubt, consult a doctor immediately. Take a chemical reagent and a container from it with you.
• In case of injury, always consult a doctor.

• Improper use of chemicals can cause injury and damage to health. Carry out only the experiments specified in the instructions.
• This set of experiments is intended only for children 12 years of age and older.
• The abilities of children differ significantly even within an age group. Therefore, parents conducting experiments with their children should decide at their own discretion which experiments are suitable for their children and will be safe for them.
• Parents should discuss safety rules with their child or children before experimenting. Particular attention must be paid to the safe handling of acids, alkalis and flammable liquids.
• Before starting experiments, clear the place of experiments from objects that may interfere with you. Storage of foodstuffs near the test site should be avoided. The test site should be well ventilated and close to a faucet or other source of water. For experiments, you need a stable table.
• Substances in disposable packaging should be used completely or disposed of after one experiment, i.e. after opening the package.

Frequently asked Questions

Dry fuel (urotropine) does not spill out of the jar. What to do?

Urotropin may stick together during storage. To still pour it out of the jar, take a black stick from the set and carefully break the lumps.

It is not possible to form urotropin. What to do?

If hemotropin is not pressed in a mold, pour it into a plastic cup and add 4 drops of water. Mix the moistened powder well and transfer back to the mould.

You can also add 3 drops of soap solution from the "Tin" kit that you received with the "Monster Chemistry" kit.

Can this snake be eaten or touched?

When working with chemicals, you need to follow an unshakable rule: never taste anything from what you get as a result of chemical reactions. Even if in theory it is a safe product. Life is often richer and more unpredictable than any theory. The product may not be what you expected, chemical glassware may contain traces of previous reactions, chemical reagents may not be clean enough. Experiments with tasting reagents can end sadly.

That is why it is forbidden to eat anything in professional laboratories. Even brought food. Safety above all!

Is it possible to touch the "snake"? Be careful, it can be hot! Coal, of which the "snake" mainly consists, can smolder. Make sure the snake is cold before you can touch it. The snake gets dirty - do not forget to wash your hands after the experience!

Other experiments

Step-by-step instruction

Take a dry fuel burner from the starter kit and put foil on it. Attention! Use a cork stand to avoid damaging your work surface.

Position the plastic ring in the center of the foil.

Pour all dry fuel (2.5 g) into the ring.

Press the mold into the ring to make a hole in the pile of dry fuel. Remove the mold carefully.

Remove the plastic ring by lightly tapping it.

Pour two level scoops of sugar (2 g) into a jar of 0.5 g of soda (NaHCO3) and close the jar with a lid.

Shake the jar for 10 seconds to mix the sugar and soda.

Pour the mixture of soda and sugar into the recess in the dry fuel.

Set fire to dry fuel - very soon a black "snake" will begin to grow from this hill!

Expected Result

Dry fuel will start to burn. A mixture of sugar and soda in the fire will begin to turn into a large black "snake". If you do everything right, then you will grow a snake 15-35 cm long.

Disposal

Dispose of the solid waste of the experiment with household waste.

What happened

Why is such a "snake" formed?

When heated, part of the sugar (C 12 H 22 O 11) burns out, turning into water vapor and carbon dioxide. Combustion requires oxygen supply. Since the flow of oxygen into the inner regions of the sugar hill is difficult, a different process takes place there: from a high temperature, sugar decomposes into coal and water vapor. This is how our “snake” turns out.

Why is soda (NaHCO 3) added to sugar?

When heated, soda decomposes with the release of carbon dioxide (CO 2):

Soda is added to the dough so that it becomes fluffy when baking. And that is why we add soda to sugar in this experiment - so that the released carbon dioxide and water vapor make the “snake” airy, light. Therefore, the snake can grow up.

What is this "snake" made of?

Basically, the "snake" consists of coal, obtained by heating sugar and not burned in the fire. It is coal that gives the “snake” such a black color. Also in its composition there is Na 2 CO 3, resulting from the decomposition of soda when heated.

What chemical reactions take place during the formation of a "snake"?

• Combustion (combination with oxygen) of sugar:

C 12 H 22 O 11 + O 2 \u003d CO 2 + H 2 O

• Thermal decomposition of sugar into charcoal and water vapor:

C 12 H 22 O 11 → C + H 2 O

• Thermal decomposition of baking soda into water vapor and carbon dioxide:

2NaHCO 3 → Na 2 CO 3 + H 2 O + CO 2

What is sugar and where does it come from?

A sugar molecule is made up of carbon (C), oxygen (O), and hydrogen (H) atoms. This is how it looks like:

Frankly, it's hard to see something here. Download the MEL Chemistry app on your smartphone or tablet and you will be able to look at the sugar molecule from different angles and better understand its structure. In the application, the sugar molecule is called Sucrose.

As you can see, this molecule consists of two parts, linked together by an oxygen atom (O). Surely you have heard the name of these two parts: glucose and fructose. They are also called simple sugars. Ordinary sugar is called compound sugar to emphasize that a sugar molecule consists of several (two) simple sugars.

This is what these simple sugars look like:

fructose

Sugars are important building blocks of plants. During photosynthesis, plants produce simple sugars from water and carbon dioxide. The latter, in turn, can combine both into short molecules (for example, sugar) and into long chains. Starch and cellulose are such long chains (polysugars) that are made up of simple sugars. Plants use them as building material and to store nutrients.

The longer the sugar molecule, the harder it is for our digestive system to digest it. That is why we love sweets containing simple short sugars so much. But our body was not designed to feed mainly on simple sugars, they are rare in nature. Therefore, be careful with the consumption of sweets!

Why does soda (NaHCO 3) decompose when heated, but table salt (NaCl) does not?

This is not an easy question. First you need to understand what is bonding energy.

Imagine a train car with a very uneven floor. This car has its own mountains, its own hollows, depressions. A sort of small Switzerland in the car. A wooden ball is rolling on the floor. If released, it will roll down the slope until it reaches the bottom of one of the depressions. We say that the ball "wants" to take up the position of minimum potential energy, which is just below the trough. Similarly, the atoms try to line up in such a configuration in which the bond energy is minimal.

There are a few subtle points here that I would like to draw your attention to. First, remember that such an explanation of what is said “on the fingers” is not very accurate, but it will suit us to understand the big picture.

So where does the ball go? To the lowest point of the car? No matter how! It will slide into the nearest depression. And, most likely, it will remain there. Maybe on the other side of the mountain there is another depression, deeper. Unfortunately, our ball does not “know” this. But if the car shakes strongly, then with a high probability the ball will jump out of its local cavity and “find” a deeper hole. There we shake a bucket of gravel to compact it. The gravel knocked out of the position of the local minimum will most likely find a more optimal configuration, and our ball will sooner reach a deeper depression.

As you may have guessed, in the microcosm, temperature is an analogue of shaking. When we heat the substance, we make the whole system "shake", as we rocked the car with the ball. Atoms break off and reattach in a variety of ways, and with a high probability they will be able to find a more optimal configuration than they were at the beginning. If it exists, of course.

We see such a process in a very large number of chemical reactions. The molecule is stable because it is located in a local cavity. If we move it a little, it will get worse, and it will return back similarly to a ball, which, if moved sideways from a local cavity a little, it will roll back. But it is worth heating this substance harder so that our “car” is properly shaken, and the molecule will find a more successful configuration. That's why dynamite won't explode until you hit it. That is why the paper will not catch fire until you heat it. They feel good in their local holes and need a noticeable effort to get them out of there, even if there is a deeper hole nearby.

Now we can return to our original question: why does soda (NaHCO 3) decompose when heated? Because it is in a state of a local minimum of binding energies. In such a hollow. Nearby there is a deeper depression. This is how we talk about the state when 2NaHCO 3 decayed into 2Na 2 CO 3 + H 2 O + CO 2. But the molecule does not “know” about this, and until we heat it up, it will not be able to get out of its local hole in order to look around and find a deeper hole. But when we heat the soda to 100-200 degrees, this process will go quickly. Soda decomposes.

Why does table salt NaCl not break down in a similar way? Because she is already in the deepest hole. If it is broken into Na and Cl or any other combination of them, the bond energy will only increase.

If you've read this far, well done! This is not the simplest text and not the simplest thoughts. I hope you managed to glean something. I want to warn you in this place! As I said at the beginning, this is a beautiful explanation, but not quite right. There are situations when the ball in the car will tend to occupy not the deepest hole. Similarly, our matter will not always tend to a state with a minimum bond energy. But more about that some other time.

Belief in miracles is born in childhood. With a delighted look, the child catches every movement of the magician, with bated breath follows the hat with a rabbit, with trepidation and hope awaits a gift from his beloved magician. A spectacle, faith in a miracle are necessary for children, and adults will not hurt to introduce a little fairy tale and delight into everyday regularity. How to do it? It's not that hard! You can please children, for example, with the appearance of a huge wriggling snake made of ordinary sand. Entertaining chemistry will come to the aid of children's animators, holiday organizers, creative parents, caring teachers.

An ordinary miracle is a pharaoh's snake made of soda and sugar, growing out of burning sand. This will be remembered for a long time! An elementary trick is easy to carry out at home, observing fire safety precautions.

And this monster appears from a harmless soda!

In one of the biblical parables, it is said that the staff of Moses turned into a snake when it touched the sand at the feet of the ruler. The spectacular display of power impressed the pharaoh in antiquity. Today, schoolchildren are surprised by the pharaoh snake, demonstrating a chemical reaction, as a result of which the ingredients increase in volume quickly and many times over. What are these incredible substances? No magic, just sand, soda, sugar and alcohol.

Ordinary sand is poured onto a ceramic plate. This material is abundant on the banks of rivers. The top of the mound is leveled, a recess is made in it. The slide is saturated with alcohol. You will have to run to the pharmacy for ethanol in advance and stock up on at least two bottles, since sand perfectly absorbs liquid. A mixture of soda and powdered sugar is laid out with a spoon on a significantly moistened mound. Proportion 1:4. For example, a spoonful of soda to four tablespoons of powdered sugar. These ingredients are in every kitchen. If there is no powder, it can be made in half a minute by pouring granulated sugar into a coffee grinder.

Everything is ready, it remains only to heat the components. It is safer to use a long-handled oven lighter, as it is easier to ignite alcohol, sugar and soda, because they can flare up instantly.

Gluconate-born snake looks like a monster from a horror movie

Essence of focus

When the flame engulfs the entire hill, the ingredients will begin to blacken, shrink, and then increase dramatically in size, forming into a curving thick snake. Under the action of high temperature, a chemical reaction of decomposition of soda occurs, it decomposes into water vapor and carbon dioxide. It is the gases obtained as a result of this process that loosen and swell the mass, forming a snake - a black product of sugar combustion.

The experience itself lasts a few minutes, but the impressions of the sight of the curving body of an almost real reptile are remembered for a long time. Soda is the safest trick ingredient, but there are other substances that can be used to display monsters.

Other experiments

Pharaoh snake from potassium permanganate

Manganese crystals are amazingly beautifully dissolved in water, gradually coloring the liquid in a soft lilac color, it seems that marvelous flowers have blossomed. It is this ability of the substance to color that is useful to the magician to demonstrate an unusual bright lilac-white snake, somewhat reminiscent of toothpaste for a giant.

Important! The experiment is carried out in a bathtub or sink, on an open lawn or sandy beach. There will be a lot of substances, so you should not risk an expensive carpet or a new sofa.

Ingredients:

• potassium permanganate from a pharmacy;
• a glass of tap water;
• liquid soap or "Fairy" for washing dishes;
• 30% hydrogen peroxide or one tablet of hydroperite from a pharmacy, diluted with water.

Lilac manganese crystals (a teaspoon) are dissolved in water, then a foaming dishwashing detergent or ordinary liquid soap (also a spoon) is poured in. The mixture is best prepared in a narrow tall glass vessel or vase. And the final touch - peroxide!

Attention! The reaction is immediate and violent. A white-lilac dense foam, similar to an exotic python, literally erupts from a glass. The column of this mass first rushes up, and then folds into large rings.

Real sand viper

Urotropin snake

Urotropin is an antiseptic. Tablets must be bought at the pharmacy. You will also need a concentrate of an aqueous solution of ammonium. On one tablet of urotropin, 10 drops of ammonium should be dripped from a syringe or pipette, then dried. And so repeat 4 times. Tablets are dried at room temperature, they can not be heated.

When the urotropin dries, the tablet is set on fire on a ceramic saucer. The temperature rises, a reaction occurs, black balls appear, quickly merging into one tight mass, which begins to wriggle and grow. What happened from the pill? Carbon, carbon dioxide, nitrogen - in general, gases that loosen the porous mass.

This is important to consider! The experiment will fail if you mix not tablets (they contain talc and paraffin), but pure urotropin and ammonium nitrate.

Pharaoh's snake from calcium gluconate

One of the simplest and most accessible tricks is to set fire to calcium gluconate tablets with dry fuel. A gray spotted snake will gradually form from each tablet. And if you set fire to the entire blister, you get a huge octopus crawling forward with tentacles. The tiny starting material expands 15-20 times to form an oxide of calcium, carbon, water, and carbon dioxide. Isn't this magic?

Experiments are carried out only under the supervision of adults.

Sulfanilamide snake

If there is an expired streptocide or fthalazol, biseptol or sulgin in the home first aid kit, then you can call the spirit of the viper. For a chemical experiment, it is enough to place a sulfanilamide tablet on dry fuel and set it on fire. The mass will swell, expand, and a noble viper with a metallic sheen will appear from the middle. However, the nature of this reptile is extremely insidious, it is really poisonous. The pungent smell of hydrogen sulfide and sulfur dioxide formed can be harmful to health.

Safety

Chemical experiments should be carried out carefully, observing elementary safety rules:

• the experimenter puts on gloves, a dressing gown;
• the surface must be fireproof;
• a bucket of water or sand is placed within reach;
• for toxic gases, a fume hood must be provided;
• if the experiment is carried out on the street, then the direction of the wind is taken into account;
• spectators do not come closer than 2 meters;
• there should be a remedy for burns in the first-aid kit;
• All experiments are carried out by an adult, children only watch.

And this is a whole octopus or hydra.

It is better to see and do it once than to hear or learn a hundred times. The child will remember the emotions that he experienced during the demonstration, plunge into the atmosphere of magic. A small everyday miracle out of nothing is quite accessible to everyone with the right organization.

Video: sand snake

Video: making a three-headed hydra

Pharaoh snakes name a number of reactions that are accompanied by the formation of a porous product from a small volume of reactants. These reactions are accompanied by rapid evolution of gas. As a result, the reaction looks as if a large snake crawls out of the mixture of reagents and crawls along the table, like a real one.

On this page you will learn about the reactions accompanied by the formation of "pharaoh's snakes", get acquainted with the equations of these reactions and you can watch impressive videos demonstrating the course of such reactions. Some of these reactions can be reproduced even at home or in a school laboratory - subject to all safety rules, of course. And the other part of the reactions, fortunately, requires the presence of such reagents, which you will not find anywhere except in specialized laboratories. Fortunately, because many of them are highly toxic, and experimenting with them is strongly discouraged.

1. Decomposition of mercury thiocyanate (thiocyanate) - Hg (CNS) 2

Thermal decomposition of mercury thiocyanate follows the equation:

2 Hg(SCN) 2 = 2 HgS + CS 2 + C 3 N 4

CS 2 + 3O 2 \u003d CO 2 + 2SO 2

When mercury thiocyanate is heated, a black salt is formed - mercury sulfide, yellow carbon nitride and carbon disulfide CS 2. The latter ignites and burns in air, forming carbon dioxide CO 2 and sulfur dioxide SO 2 .

Carbon nitride swells with the resulting gases, while moving it captures black mercury (II) sulfide, and a yellow-black porous mass is obtained.

As a result, a large black-and-yellow "snake" emerges from a piece of mercury thiocyanate, resembling a snake, or even more than one. The blue flame from which the "snake" crawls out is the flame of burning carbon disulfide CS 2 . From 1 g of ammonium thiocyanate and 2.5 g of mercury nitrate, in skillful hands, a snake 20-30 cm long can be obtained.

The decomposition of mercury thiocyanate is the first discovered reaction of this type. Its discoverer is Friedrich Wöhler (1800-1882), a student at Heidelberg University. One day in the fall of 1820, while mixing aqueous solutions of ammonium thiocyanate NH 4 NCS and mercury nitrate Hg(NO 3) 2 , he discovered that a white precipitate formed from the solution. Wöhler filtered the solution and dried the precipitate of the resulting mercury thiocyanate Hg(NCS) 2 . Out of curiosity, the researcher set fire to it. The sediment caught fire and a miracle happened: a long black-and-yellow "snake" crawled out of a nondescript white lump, wriggling, and began to grow.

Mercury salts are poisonous, and handling them requires care and attention. It is safer to show a dichromatic snake.

2. Dichromate snake

Method 1. Mix 10 g of potassium dichromate K 2 Cr 2 O 7 , 5 g of potassium nitrate KNO 3 and 10 g of sugar (sucrose) C 12 H 22 O 11 . Then the mixture is ground in a mortar and moistened with ethyl alcohol C 2 H 5 OH or collodion (it is sold at a pharmacy). Then this mixture is pressed into a glass tube with a diameter of 5–8 mm.

The resulting column is pushed out of the tube and set on fire at one end. A barely noticeable light flashes, from under which a black, and then a green “snake” begins to crawl out. A mixture column with a diameter of 4 mm burns at a rate of 2 mm per second. When burning, it can lengthen 10 times!

The combustion reaction of sucrose in the presence of two oxidizers, potassium nitrate and potassium dichromate, is rather complex. The reaction products are black soot particles, green chromium (III) oxide Cr 2 O 3 , potassium carbonate melt K 2 CO 3 , carbon dioxide CO 2 and potassium nitrite KNO 2 . Carbon dioxide CO 2 puffs up the mixture of solids and makes it move.

Method 2. Mix 1 g of ammonium dichromate (NH 4) 2 Cr 2 O 7 2 g of ammonium nitrate NH 4 NO 3 and 1 g of powdered sugar. Moisten the mixture with water, fashion a stick out of it and air dry. If the wand is set on fire, black-and-green "snakes" will crawl from it in different directions.

When the mixture is ignited, the following reactions occur:

(NH 4) 2 Cr 2 O 7 \u003d Cr 2 O 3 + N 2 + 4H 2 O,

NH 4 NO 3 \u003d N 2 O + 2H 2 O,

C 12 H 22 O 11 + 6O 2 \u003d 6CO 2 + 11H 2 O + 6C.

The decomposition of ammonium dichromate produces nitrogen N 2 , water vapor and green chromium oxide (III) Cr 2 O 3 . The reaction proceeds with the release of heat. In the reaction of thermal decomposition of ammonium nitrate, a colorless gas is released - dinitrogen oxide N 2 O, which, even at low heating, decomposes into oxygen O 2 and nitrogen N 2. The combustion of sugar produces another gas - carbon dioxide CO 2 , in addition, charring occurs - the release of carbon. A large volume of gases plus solid oxidation products is the secret to the "snake" behavior of the mixture.

3. Soda and Sugar Viper

To conduct this experiment, 3–4 tablespoons of dry, sifted river sand are poured into a dinner plate and a hill is made from it with a depression at the top. Then prepare a mixture consisting of 1 teaspoon of powdered sugar and 1/4 teaspoon of sodium bicarbonate NaHCO 3 (baking soda). The sand is impregnated with a 96–98% solution of ethanol C 2 H 5 OH and the prepared reaction mixture is poured into the recess of the hill. Then the hill is set on fire.

The alcohol will burn. After 3-4 minutes, black balls appear on the surface of the mixture, and a black liquid appears at the base of the slide. When almost all the alcohol is burned, the mixture turns black, and a thick black "viper" slowly crawls out of the sand. At the base, it is surrounded by a "collar" of burning alcohol.

In this mass, the following reactions take place:

2NaHCO 3 \u003d Na 2 CO 3 + H 2 O + CO 2,

C 2 H 5 OH + 3O 2 \u003d 2CO 2 + 3H 2 O

Carbon dioxide CO 2, released during the decomposition of sodium bicarbonate and the combustion of ethyl alcohol, as well as water vapor, swell the burning mass, causing it to crawl like a snake. The longer the alcohol burns, the longer the "snake" turns out. It consists of sodium carbonate Na 2 CO 3 mixed with tiny particles of coal formed during the combustion of sugar.

Instead of sodium bicarbonate, ammonium nitrate NH 4 NO 3 can be used. 3-4 tablespoons of sifted river sand are poured into a table plate, a hill is made from it with a recess at the top and a reaction mixture is prepared, consisting of 1/2 teaspoon of ammonium nitrate and 1/2 teaspoon of powdered sugar, carefully ground in a mortar. Then, 1/2 tablespoon of ethyl alcohol is poured into the recess of the slide and 1 teaspoon of the prepared nitrate-sugar mixture is poured. Now, if you set fire to alcohol, black balls of charred sugar immediately appear on the surface of the mixture, and after them a black shiny and thick "worm" grows. If the nitrate-sugar mixture was taken no more than 1 teaspoon, then the length of the worm will not exceed 3-4 cm. And its thickness depends on the diameter of the recess of the slide.

The appearance of the worm is caused by the interaction of ammonium nitrate with sugar, which is expressed by the following equation:

2NH 4 NO 3 + C 12 H 22 O 11 \u003d 11C + 2N 2 + CO 2 + 15H 2 O.

The "worm" is set in motion by gases: nitrogen N 2 , carbon dioxide CO 2 and water vapor.

5. "Black boa" from a glass

This experience is an impressive sight. Powdered sugar in an amount of 75 g is placed in a tall glass beaker, moistened with 5–7 ml of water and stirred with a long glass rod. Then 30-40 ml of concentrated sulfuric acid H 2 SO 4 is poured over this stick to wet sugar. The mixture is then quickly stirred with a glass rod and left in the beaker.

After 1–2 minutes, the contents of the glass begin to blacken, swell and rise in the form of a voluminous, loose and spongy mass, dragging the glass rod upwards. The mixture in the glass gets very hot, even smokes a little, and slowly crawls out of the glass.

Sulfuric acid takes away water from sugar (sucrose C 12 H 22 O 11), destroying its molecular structure, and oxidizes it, turning into sulfur dioxide SO 2. When sugar is oxidized, carbon dioxide CO 2 is produced. These gases swell the formed coal and push it out of the glass along with the stick.

The equation that conveys these chemical transformations looks like this:

C 12 H 22 O 11 + 2H 2 SO 4 \u003d 11C + 2SO 2 + CO 2 + 13H 2 O.

Carbon dioxide and sulfur, together with water vapor, increase the volume of the reaction mass and cause it to rise up in a narrow glass.

You need to be patient for this experience, but it's worth it!

For the experiment, you will need urotropine (hexamethylenetetramine - (CH 2) 6 N 4). Urotropin tablets can be bought at a pharmacy - this is an antiseptic drug. “Hard spirit” (dry fuel) is also suitable - it can be purchased at a hardware store. Just make sure the dry fuel you buy contains urotropin - it comes in many varieties. To make sure that dry fuel contains urotropin, conduct a simple experiment. Break off a few pieces of dry fuel, put them in a test tube and heat a little. If it consists of urotropine, you will smell ammonia.

To make a "snake", you need to perform the following steps. Put one tablet of “solid alcohol” or pharmacy hexamine on a saucer and soak 3-4 times with a concentrated aqueous solution of ammonium nitrate NH 4 NO 3, dropping it from a pipette and then drying it. Each time it is necessary to apply 5-10 drops (0.5 ml of solution).

Drying the tablets is the most tedious part of the experience: at room temperature in air, it takes too long. But it is impossible to raise the temperature to speed up the process - urotropine decomposes at high temperatures. Moreover, it is impossible to dry the tablets on an open fire: they can catch fire.

The impregnated and dried tablet on a saucer should be set on fire on one side. And then miracles will begin: black balls of boiling liquid will appear, which merge together and form a kind of growing “tail”. It bends, and behind it the thick body of the “snake” grows out of the fire. The “snake” grows, rests its tail against the saucer, begins to bend.

The decomposition of urotropine (CH 2) 6 N 4 in a mixture with ammonium nitrate NH 4 NO 3 leads to the formation of a porous mass consisting of carbon and a large amount of gases - carbon dioxide CO 2, nitrogen N 2 and water:

(CH 2) 6 N 4 + 2NH 4 NO 3 + 7O 2 = 10C + 6N 2 + 2CO 2 + 16H 2 O

Interestingly, if you mix chemically pure urotropine and ammonium nitrate, they decompose without forming solid products. But binders - paraffin and talc - are added to the tablets at the stage of their formation. That is why the "body of the snake" appears. And the released gases swell and move it.

This is the easiest and safest way to get a gluconate snake - just bring a pill to the flame gluconatecalcium, which is sold in every pharmacy. You can put a tablet of calcium glucanate on a tablet of dry alcohol and set it on fire. A light gray "snake" with white spots will crawl out of the tablet, the volume of which far exceeds the volume of the original substance - it can reach a length of 10-15 cm.

The decomposition of calcium gluconate having the composition Ca 2 · H 2 O leads to the formation of calcium oxide, carbon, carbon dioxide and water.

The light shade of the "snake" gives calcium oxide.

The disadvantage of the resulting "snake" is its fragility - it crumbles quite easily.

8. Sulfanilamide Pharaoh Serpent

A very simple way to obtain "pharaoh's snakes" is the oxidative decomposition of sulfanilamide drugs (these include, for example, streptocid, sulgin, sulfadimethoxine, etazol, sulfadimezin, ftalazol, biseptol). During the oxidation of sulfanilamide preparations, many gaseous reaction products (SO 2 , H 2 S , N 2 , water vapor) are released, which swell the mass and form a porous "snake".

The experiment is carried out only under traction!

1 tablet of the drug is placed on a tablet of dry fuel and the fuel is ignited. In this case, a brilliant “pharaoh’s snake” of gray color is highlighted.

In its structure, the "snake" resembles corn sticks. If you carefully pick up the prominent “snake” with tweezers and carefully pull it out, you can get a fairly long “copy”.

9. Decomposition of nitroacetanilide

For the experiment you will need: a porcelain crucible, a triangle, a tripod, a burner, a glass rod, a spatula. Follow the rules for working with concentrated sulfuric acid. When performing the experiment, do not bend over the crucible. The experiment is performed under traction.

Mix in a porcelain crucible a white organic substance - nitroacetanilide and sulfuric acid. Let's heat up the mixture. After a few seconds, a black mass will shoot out of the crucible. The released gases make the mass very porous and friable.

The black color of the mass gives carbon, which is formed in large quantities. In even greater quantities during the reaction gases SO 2 , NO 2 and CO 2 are formed, which foam the carbon.

By the way...

And why "Pharaoh snakes"? Serpents - understandable, but why pharaohs? The following explanation can be found in the literature: “One of the biblical traditions says how the prophet Moses, having exhausted all other arguments in a dispute with the pharaoh, performed a miracle, turning the rod into a writhing snake ... Pharaoh was shamed and frightened, Moses received permission to leave Egypt and the world got another riddle." It sounds exhaustive, but there is only a catch: according to the Bible (the book "Exodus"), the prophet Moses convinced the pharaoh to release the Jews from slavery, using far powerful arguments; they were called "The Ten Plagues of Egypt". These were various troubles that the Lord sent to Egypt after the next refusal of the pharaoh to let the Jewish people go. None of them, by the way, was in any way connected with snakes. Some of these terrible miracles were indeed accompanied by the waving of the famous wand. And he is famous for the fact that he really had to be a snake, but it was not Moses who did this miracle, but the Lord himself, when he assigned a great mission to him, and Moses began to show cowardice.
Thus, it remains unclear why the chemical snakes were called "Pharaoh's." Perhaps only because such a name sounds solid - to match the showiness of this type of reaction.

In preparing the material, information from the site was used