Chemical experience of bromine with aluminum

If you place a few milliliters of bromine in a test tube made of heat-resistant glass and carefully lower a piece of bromine into it aluminum foil, then after a while (necessary for bromine to penetrate through the oxide film), a violent reaction will begin. From the heat released, aluminum melts and, in the form of a small fireball, rolls over the surface of bromine (the density of liquid aluminum is less than the density of bromine), rapidly decreasing in size. The test tube is filled with bromine vapor and white smoke, consisting of the smallest crystals of aluminum bromide:

2Al+3Br 2 → 2AlBr 3 .

It is also interesting to observe the reaction of aluminum with iodine. Mix in a porcelain cup a small amount of powdered iodine with aluminum powder. While the reaction is not noticeable: in the absence of water, it proceeds extremely slowly. Using a long pipette, drop a few drops of water on the mixture, which plays the role of an initiator, and the reaction will proceed vigorously - with the formation of a flame and the release of purple vapors of iodine.

Chemical experiments with gunpowder: how gunpowder explodes!

Gunpowder

Smoky, or black, gunpowder is a mixture of potassium nitrate (potassium nitrate - KNO 3), sulfur (S) and coal (C). It ignites at a temperature of about 300 °C. Gunpowder can also explode on impact. It consists of an oxidizing agent (nitrate) and a reducing agent (charcoal). Sulfur is also a reducing agent, but its main function is to bind potassium into a strong compound. During the combustion of gunpowder, the following reaction occurs:

2KNO 3 + ЗС + S → K 2 S + N 2 + 3СО 2,
- as a result of which large volume gaseous substances. The use of gunpowder in military affairs is connected with this: the gases formed during the explosion and expanding from the heat of the reaction push the bullet out of the gun barrel. It is easy to verify the formation of potassium sulfide by smelling the barrel of a gun. It smells of hydrogen sulfide - a product of the hydrolysis of potassium sulfide.

Chemical experiments with saltpeter: fiery inscription

Spectacular chemical experience can be carried out with potassium nitrate. Let me remind you that nitrates are complex substances - salts of nitric acid. In this case, we need potassium nitrate. Its chemical formula is KNO 3 . On a sheet of paper, draw a contour, a drawing (for greater effect, let the lines do not intersect!). Prepare a concentrated solution of potassium nitrate. For information: in 15 ml hot water 20 g of KNO 3 are dissolved. Then, using a brush, we impregnate the paper along the drawn contour, while leaving no gaps or gaps. let the paper dry. Now you need to touch a burning splinter to some point on the contour. Immediately a "spark" will appear, which will slowly move along the contour of the picture until it closes it completely. Here's what happens: Potassium nitrate decomposes according to the equation:

2KNO 3 → 2 KNO 2 + O 2 .

Here KNO 2 +O 2 is a salt of nitrous acid. From the released oxygen, the paper chars and burns. For greater effect, the experiment can be carried out in a dark room.

Chemical experience of dissolving glass in hydrofluoric acid

Glass dissolves
in hydrofluoric acid

Indeed, glass dissolves easily. Glass is a very viscous liquid. The fact that glass can dissolve can be verified by performing the following chemical reaction. Hydrofluoric acid is an acid formed by dissolving hydrogen fluoride (HF) in water. It is also called hydrofluoric acid. For greater clarity, let's take a thin speckle, on which we attach a weight. We lower the glass with a weight into a solution of hydrofluoric acid. When the glass dissolves in the acid, the weight will fall to the bottom of the flask.

Chemical experiments with smoke emission

Chemical reactions with
smoke emission
(ammonium chloride)

Let's spend beautiful experience producing thick white smoke. To do this, we need to prepare a mixture of potash (potassium carbonate K 2 CO 3) with an ammonia solution (ammonia). Mix the reagents: potash and ammonia. Add a solution of hydrochloric acid to the resulting mixture. The reaction will begin already at the moment when the flask with hydrochloric acid will be brought close to the flask containing ammonia. Carefully add hydrochloric acid to the ammonia solution and observe the formation of a thick white vapor of ammonium chloride, the chemical formula of which is NH 4 Cl. The chemical reaction between ammonia and hydrochloric acid proceeds as follows:

HCl + NH 3 → NH 4 Cl

Chemical experiments: the glow of solutions

Glow reaction solution

As noted above, the glow of solutions is a sign chemical reaction. Let's conduct another spectacular experiment, in which our solution will glow. For the reaction, we need a solution of luminol, a solution of hydrogen peroxide H 2 O 2 and crystals of red blood salt K 3. Luminol- complex organic matter, whose formula is C 8 H 7 N 3 O 2. Luminol is highly soluble in some organic solvents, while it does not dissolve in water. The glow occurs when luminol reacts with some oxidizing agents in an alkaline medium.

So, let's start: add a solution of hydrogen peroxide to luminol, then add a handful of red blood salt crystals to the resulting solution. For greater effect, try experimenting with dark room! As soon as the blood red salt crystals touch the solution, a cold blue glow will immediately be noticeable, which indicates the course of the reaction. The glow in a chemical reaction is called chemiluminescence

Another chemical experience with luminous solutions:

For it, we need: hydroquinone (formerly used in photographic equipment), potassium carbonate K 2 CO 3 (also known as "potash"), pharmacy solution of formalin (formaldehyde) and hydrogen peroxide. Dissolve 1 g of hydroquinone and 5 g of potassium carbonate K 2 CO 3 in 40 ml of pharmacy formalin (formaldehyde aqueous solution). Pour this reaction mixture into a large flask or bottle with a capacity of at least one liter. In a small vessel, prepare 15 ml of concentrated hydrogen peroxide solution. You can use hydroperite tablets - a combination of hydrogen peroxide with urea (urea will not interfere with the experiment). For more effect go to dark room when your eyes have adjusted to the dark, pour the hydrogen peroxide solution into large vessel with hydroquinone. The mixture will begin to foam (hence the need for a large vessel) and a distinct orange glow will appear!

The chemical reactions in which the glow appears do not occur only during oxidation. Sometimes the glow occurs during crystallization. The easiest way to observe it is table salt. Dissolve table salt in water, and take enough salt so that undissolved crystals remain at the bottom of the glass. Pour the resulting saturated solution into another glass and add concentrated hydrochloric acid to this solution drop by drop. The salt will begin to crystallize, and sparks will fly through the solution. It is most beautiful if the experience is set in the dark!

Chemical experiments with chromium and its compounds

Multicolored chrome!... The color of chromium salts can easily change from purple to green and vice versa. Let's carry out the reaction: let's dissolve in water a few purple crystals of chromium chloride CrCl 3 6H 2 O. When boiling, the purple solution of this salt turns green. When the green solution is evaporated, a green powder of the same composition as the original salt is formed. And if you saturate a green solution of chromium chloride cooled to 0 ° C with hydrogen chloride (HCl), its color will turn purple again. How to explain the observed phenomenon? This is a rare example of isomerism in inorganic chemistry - the existence of substances that have the same composition, but different structure and properties. In the violet salt, the chromium atom is bonded to six water molecules, and the chlorine atoms are counterions: Cl 3, and in green chromium chloride they change places: Cl 2H 2 O. In an acidic environment, dichromates are strong oxidizing agents. Their recovery products are Cr3+ ions:

K 2 Cr 2 O 7 + 4H 2 SO 4 + 3K 2 SO 3 → Cr 2 (SO 4) 3 + 4K 2 SO 4 + 4H 2 O.

Potassium chromate (yellow)
dichromate - (red)

At low temperature from the resulting solution, it is possible to isolate purple crystals of potassium chromium alum KCr (SO 4) 2 12H 2 O. The dark red solution obtained by adding concentrated sulfuric acid to a saturated aqueous solution of potassium dichromate is called “chromic peak”. In laboratories, it is used for washing and degreasing chemical glassware. The dishes are carefully rinsed with chromic, which is not poured into the sink, but is used repeatedly. In the end, the mixture becomes green - all the chromium in such a solution has already passed into the Cr 3+ form. A particularly strong oxidizing agent is chromium (VI) oxide CrO 3 . With it, you can light an alcohol lamp without matches: just touch the wick moistened with alcohol with a stick with several crystals of this substance. When CrO 3 is decomposed, dark brown chromium (IV) oxide powder CrO 2 can be obtained. It has ferromagnetic properties and is used in the magnetic tapes of some types of audio cassettes. The body of an adult contains only about 6 mg of chromium. Many compounds of this element (especially chromates and dichromates) are toxic, and some of them are carcinogens, i.e. capable of causing cancer.

Chemical experiments: the reducing properties of iron

Ferric chloride III

This type chemical reaction refers to redox reactions. To carry out the reaction, we need diluted (5%) aqueous solutions of iron (III) chloride FeCl 3 and the same solution of potassium iodide KI. So, a solution of iron (III) chloride is poured into one flask. Then add a few drops of potassium iodide solution to it. Observe the color change of the solution. The liquid will take on a reddish-brown color. The following chemical reactions will take place in the solution:

2FeCl 3 + 2KI → 2FeCl 2 + 2KCl + I 2

KI + I 2 → K

Ferric chloride II

Another chemical experiment with iron compounds. For it, we need dilute (10–15%) aqueous solutions of iron (II) sulfate FeSO 4 and ammonium thiocyanate NH 4 NCS, bromine water Br 2. Let's start. Pour a solution of iron(II) sulfate into one flask. 3-5 drops of ammonium thiocyanate solution are also added there. We notice that there are no signs of chemical reactions. Of course, iron(II) cations do not form colored complexes with thiocyanate ions. Now add bromine water to this flask. But now the iron ions "given themselves out" and colored the solution in a blood-red color. this is how the (III) ion of valence iron reacts with thiocyanate ions. Here's what happened in the flask:

Fe(H 2 O) 6 ] 3+ + n NCS– (n–3) – + n H 2 O

Chemical experiment on the dehydration of sugar with sulfuric acid

Sugar dehydration
sulfuric acid

Concentrated sulfuric acid dehydrates the sugar. Sugar is a complex organic substance whose formula is C 12 H 22 O 11. Here's how it goes. Powdered sugar is placed in a tall glass beaker, slightly moistened with water. Then a little concentrated sulfuric acid is added to the wet sugar. mix gently and quickly with a glass rod. The stick is left in the middle of the glass with the mixture. After 1 - 2 minutes, the sugar begins to turn black, swell and rise in the form of a voluminous, loose black mass, taking the glass rod with it. The mixture in the glass gets very hot and smokes a little. In this chemical reaction, sulfuric acid not only removes water from sugar, but also partially turns it into coal.

C 12 H 22 O 11 + 2H 2 SO 4 (conc.) → 11C + CO 2 + 13H 2 O + 2SO 2

The released water during such a chemical reaction is mainly absorbed by sulfuric acid (sulfuric acid "greedily" absorbs water) with the formation of hydrates, hence the strong release of heat. And carbon dioxide CO 2, which is obtained during the oxidation of sugar, and sulfur dioxide SO 2 raise the charring mixture up.

Chemical experiment with the disappearance of an aluminum spoon

Mercury nitrate solution

Let's carry out another funny chemical reaction: for this we need an aluminum spoon and mercury nitrate (Hg (NO 3) 2). So, let's take a spoon, clean it with a fine-grained sandpaper then degrease with acetone. Dip a spoon for a few seconds in a solution of mercury nitrate (Hg (NO 3) 2). (remember that mercury compounds are poisonous!). As soon as the surface of the aluminum spoon in the mercury solution becomes gray color, the spoon must be removed, washed with boiled water and dried (wetting, but not wiping). After a few seconds, the metal spoon will turn into fluffy white flakes, and soon only a grayish pile of ash will be left of it. This is what happened:

Al + 3 Hg(NO 3) 2 → 3 Hg + 2 Al(NO 3) 3 .

In the solution, at the beginning of the reaction, a thin layer of aluminum amalgam (an alloy of aluminum and mercury) appears on the surface of the spoon. The amalgam then turns into fluffy white flakes of aluminum hydroxide (Al(OH) 3). The metal consumed in the reaction is replenished with new portions of aluminum dissolved in mercury. And, finally, instead of a shiny spoon, white Al (OH) 3 powder and tiny droplets of mercury remain on the paper. If after a solution of mercury nitrate (Hg (NO 3) 2) aluminum spoon immediately immerse in distilled water, then gas bubbles and scales will appear on its surface white color(hydrogen and aluminum hydroxide will be released).

B.D. STEPIN, L.YU.ALIKBEROVA

Spectacular experiments in chemistry

Where does the passion for chemistry begin - a science full of amazing mysteries, mysterious and incomprehensible phenomena? Very often - from chemical experiments, which are accompanied by colorful effects, "miracles". And it has always been so, at least there is a lot of historical evidence for this.

The materials under the heading "Chemistry at school and at home" will describe simple and interesting experiments. All of them work well if you strictly follow the recommendations given: after all, the course of a reaction is often affected by temperature, the degree of grinding of substances, the concentration of solutions, the presence of impurities in the starting substances, the ratio of the reacting components, and even the order in which they are added to each other.

Any chemical experiments require caution, attention and accuracy when performing. Three simple rules will help you avoid unpleasant surprises.

First: no need to experiment at home with unfamiliar substances. Don't forget that too large quantities well-known chemicals in the wrong hands can also become dangerous. Never exceed the amounts of substances indicated in the test description.

Second: before performing any experiment, one must carefully read its description and understand the properties of the substances used. For this there are textbooks, reference books and other literature.

Third: you have to be careful and prudent. If experiments are related to combustion, the formation of smoke and harmful gases, they should be shown where this will not cause unpleasant consequences, for example, in a fume hood during classes in a chemistry circle or under open sky. If during the experiment some substances are scattered or splashed, then it is necessary to protect yourself with goggles or a screen, and seat the audience at a safe distance. All experiments with strong acids and alkalis should be carried out wearing goggles and rubber gloves. Experiments marked with an asterisk (*) can only be performed by a teacher or leader of a chemistry circle.

If these rules are observed, the experiments will be successful. Then the chemicals will reveal to you the wonders of their transformations.

Christmas tree in the snow

For this experiment, you need to get a glass bell, small aquarium, in extreme cases - a five-liter glass jar with a wide neck. You also need a flat board or sheet of plywood on which these vessels will be installed upside down. You will also need a small plastic toy Christmas tree. Perform the experiment as follows.

First, a plastic Christmas tree is sprayed in a fume hood with concentrated hydrochloric acid and immediately placed under a bell, jar or aquarium (Fig. 1). The Christmas tree is kept under the bell for 10–15 minutes, then quickly, slightly raising the bell, a small cup with a concentrated ammonia solution is placed next to the Christmas tree. Immediately, crystalline “snow” appears in the air under the bell, which settles on the Christmas tree, and soon the whole of it is covered with crystals that look like frost.

This effect is caused by the reaction of hydrogen chloride with ammonia:

Hcl + NH 3 = NH 4 Cl,

which leads to the formation of the smallest colorless crystals of ammonium chloride, showering the Christmas tree.

sparkling crystals

How to believe that a substance, when crystallized from an aqueous solution, emits a sheaf of sparks under water? But try mixing 108 g of potassium sulfate K 2 SO 4 and 100 g of sodium sulfate decahydrate Na 2 SO 4 10H 2 O (Glauber's salt) and add in portions with stirring a little hot distilled or boiled water until all the crystals are dissolved. Leave the solution in the dark so that, upon cooling, the crystallization of the double salt of the composition Na 2 SO 4 2K 2 SO 4 10H 2 O begins. As soon as the crystals begin to stand out, the solution will sparkle: at 60 ° C weakly, and as it cools, more and more. When a lot of crystals fall out, you will see a whole sheaf of sparks.

The glow and the formation of sparks are caused by the fact that during the crystallization of the double salt, which is obtained by the reaction

2K 2 SO 4 + Na 2 SO 4 + 10H 2 O \u003d Na 2 SO 4 2K 2 SO 4 10H 2 O,

a lot of energy is released, almost completely converted into light.

orange light

The appearance of this amazing glow is caused by almost complete transformation the energy of a chemical reaction into light. To observe it, a 10–15% solution of potassium carbonate K 2 CO 3 is added to a saturated aqueous solution of hydroquinone C 6 H 4 (OH) 2, formalin is an aqueous solution of formaldehyde HCHO and perhydrol is a concentrated solution of hydrogen peroxide H 2 O 2. The glow of the liquid is best observed in the dark.

The reason for the release of light is the redox reactions of the conversion of hydroquinone C 6 H 4 (OH) 2 into quinone C 6 H 4 O 2, and formaldehyde HCHO into formic acid HCOOH:

C 6 H 4 (OH) 2 + H 2 O 2 \u003d C 6 H 4 O 2 + 2H 2 O,

HCNO + H 2 O 2 \u003d HCOOH + H 2 O.

At the same time, the reaction of neutralization of formic acid with potassium carbonate proceeds with the formation of a salt - potassium formate HCOOK - and the release of carbon dioxide CO 2 ( carbon dioxide), so the solution foams:

2HCOOH + K 2 CO 3 \u003d 2HSOOK + CO 2 + H 2 O.

Hydroquinone (1,4-hydroxybenzene) is a colorless crystalline substance. The hydroquinone molecule contains a benzene ring in which two hydrogen atoms in the para position are replaced by two hydroxyl groups.

Thunderstorm in a glass

"Thunder" and "lightning" in a glass of water? It turns out that it happens! First, weigh 5–6 g of potassium bromate KBrO 3 and 5–6 g of barium chloride dihydrate BaC 12 2H 2 O and dissolve these colorless crystalline substances when heated in 100 g of distilled water, and then mix the resulting solutions. When the mixture is cooled, a precipitate of barium bromate Ba (BrO 3) 2, which is slightly soluble in the cold, will precipitate:

2KBrO 3 + BaCl 2 = Ba (BrO 3) 2 + 2KSl.

Filter off the precipitated colorless precipitate of Ba(BrO 3) 2 crystals and wash it 2-3 times with small (5-10 ml) portions of cold water. Then air dry the washed precipitate. After that, dissolve 2 g of the resulting Ba(BrO 3) 2 in 50 ml of boiling water and filter the still hot solution.

Place the glass with the filtrate to cool to 40–45 °C. This is best done in a water bath heated to the same temperature. Check the temperature of the bath with a thermometer and, if it drops, heat the water again with an electric hotplate.

Close the windows with curtains or turn off the light in the room, and you will see how in the glass, simultaneously with the appearance of crystals, blue sparks will appear in one place or another - "lightning" and pops of "thunder" will be heard. Here's a "thunderstorm" in a glass! The light effect is caused by the release of energy during crystallization, and the pops are caused by the appearance of crystals.

Smoke from the water

Poured into a glass tap water and throw a piece of "dry ice" - solid carbon dioxide CO 2 - into it. The water will immediately bubble up, and a thick white "smoke" will pour out of the glass, formed by the cooled vapors of water, which are carried away by the rising carbon dioxide. This "smoke" is completely safe.

Carbon dioxide. Solid carbon dioxide sublimes without melting at a low temperature of -78 °C. AT liquid state CO 2 can only be under pressure. Gaseous carbon dioxide is a colorless, non-flammable gas with a slightly sour taste. Water is able to dissolve a significant amount of gaseous CO 2: 1 liter of water at 20 ° C and a pressure of 1 atm absorbs about 0.9 liters of CO 2. A very small part of dissolved CO2 interacts with water, and carbonic acid H 2 CO 3 is formed, which only partially interacts with water molecules, forming oxonium ions H 3 O + and bicarbonate ions HCO 3 -:

H 2 CO 3 + H 2 O HCO 3 - + H 3 O +,

HCO 3 - + H 2 O CO 3 2- + H 3 O +.

Mysterious Disappearance

Chromium(III) oxide will help to show how the substance disappears without a trace, disappears without flame and smoke. For this, several tablets of “dry alcohol” (solid fuel based on urotropine) are stacked in a pile, and a pinch of chromium (III) oxide Cr 2 O 3 preheated in a metal spoon is poured on top. And what? There is no flame, no smoke, and the slide is gradually decreasing in size. After some time, only a pinch of unused green powder remains from it - the Cr 2 O 3 catalyst.

Oxidation of urotropine (CH 2) 6 N 4 (hexamethylenetetramine) - the basis of solid alcohol - in the presence of a Cr 2 O 3 catalyst proceeds according to the reaction:

(CH 2) 6 N 4 + 9O 2 \u003d 6CO 2 + 2N 2 + 6H 2 O,

where all products - carbon dioxide CO 2, nitrogen N 2 and water vapor H 2 O - are gaseous, colorless and odorless. It is impossible to notice their disappearance.

Acetone and copper wire

One more experiment can be shown with the mysterious disappearance of a substance, which at first glance seems to be just sorcery. Copper wire 0.8–1.0 mm thick is prepared: it is cleaned with sandpaper and rolled into a ring 3–4 cm in diameter. the end of this segment is put on a piece of pencil, from which the stylus has been removed in advance.

Then pour 10-15 ml of acetone (CH 3) 2 CO into a glass (do not forget: acetone is flammable!).

Away from the beaker of acetone, a ring of copper wire, holding it by the handle, and then quickly lower it into a glass of acetone so that the ring does not touch the surface of the liquid and is 5–10 mm from it (Fig. 2). The wire will become hot and will glow until all the acetone is used up. But there will be no flame, no smoke! To make the experience even more spectacular, the lights are turned off in the room.

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Rice. 2. Disappearance of acetone

On the copper surface, which serves as a catalyst and accelerates the reaction, acetone vapor is oxidized to acetic acid CH 3 COOH and acetaldehyde CH 3 CHO:

2 (CH 3) 2 CO + O 2 \u003d CH 3 COOH + 2CH 3 CHO,

with emphasis a large number heat, so the wire becomes red hot. The vapors of both reaction products are colorless, only the smell gives them away.

"Dry Acid"

If you put a piece of "dry ice" - solid carbon dioxide - into a flask and close it with a cork with a gas outlet tube, and lower the end of this tube into a test tube with water, to which blue litmus has been added in advance, then a small miracle will soon happen.

Warm up the flask slightly. Very soon, the blue litmus in the test tube will turn red. This means that carbon dioxide is an acidic oxide, when it reacts with water, carbonic acid is obtained, which undergoes protolysis, and the environment becomes acidic:

H 2 CO 3 + H 2 O HCO 3 - + H 3 O +.

magic egg

How to clean egg without breaking the shell? If you lower it into dilute hydrochloric or nitric acid, then the shell will completely dissolve and the protein and yolk will remain, surrounded by a thin film.

This experience can be demonstrated very spectacular way. It is necessary to take a flask or a glass bottle with a wide mouth, pour into it 3/4 of the volume of dilute hydrochloric or nitric acid, put a raw egg on the neck of the flask, and then carefully warm the contents of the flask. When the acid begins to evaporate, the shell will dissolve, and after a short time, the egg in the elastic film will slip into the vessel with acid (although the egg is larger in cross section than the neck of the flask).

The chemical dissolution of the egg shell, the main component of which is calcium carbonate, corresponds to the reaction equation.

Evening of entertaining chemistry

When preparing a chemical evening, careful preparation of the teacher for conducting experiments is required.

The evening should be preceded by long, careful work with students, and one student should not be assigned more than two experiments.

The purpose of the chemistry evening- repeat the knowledge gained, deepen students' interest in chemistry and instill in them practical skills in developing and implementing experiments.

Description of the main stages of the evening of entertaining chemistry

I. Introductory speech of the teacher on the topic "The role of chemistry in the life of society."

II. Entertaining experiences in chemistry.

Leading (the role of the leader is performed by one of the students of the 10-11th grade):

Today we are having an evening of entertaining chemistry. Your task is to carefully follow the chemical experiments and try to explain them. And so, we begin! Experience No. 1: "Volcano".

Experience number 1. Description:

A participant in the evening pours powdered ammonium dichromate (in the form of a slide) onto an asbestos net, on upper part Gorki puts several heads of matches and sets them on fire with a splinter.

Note: The volcano will look even more spectacular if you add a little powdered magnesium to the ammonium dichromate. Mix the components of the mixture immediately, because. magnesium burns vigorously and being in one place causes the scattering of hot particles.

The essence of the experiment is the exothermic decomposition of ammonium dichromate under local heating.

There is no smoke without fire, says an old Russian proverb. It turns out that with the help of chemistry you can get smoke without fire. And so, attention!

Experience number 2. Description:

The participant of the evening takes two glass rods, on which a little cotton wool is wound, and wets them: one in concentrated nitric (or hydrochloric) acid, the other in an aqueous 25% ammonia solution. Sticks should be brought to each other. White smoke rises from the sticks.

The essence of the experience is the formation of nitrate (chloride) ammonium.

And now we present to your attention the following experience - “Shooting Paper”.

Experience number 3. Description:

The participant of the evening takes out pieces of paper on a sheet of plywood, touches them with a glass rod. When you touch each leaf, a shot is heard.

Note: Narrow strips of filter paper are cut in advance and moistened in a solution of iodine in ammonia. After that, the strips are laid out on a sheet of plywood and left to dry until the evening. The shot is the stronger, the better the paper is impregnated with the solution and the more concentrated the solution of nitrogen iodide was.

The essence of the experiment is the exothermic decomposition of the fragile compound NI3*NH3.

I have an egg. Which one of you guys will peel it without breaking the shells?

Experience number 4. Description:

The participant of the evening places the egg in a crystallizer with a solution of hydrochloric (or acetic) acid. After a while, it pulls out an egg covered only with a shell membrane.

The essence of the experience is that the composition of the shell mainly includes calcium carbonate. In hydrochloric (acetic) acid, it turns into soluble calcium chloride (calcium acetate).

Guys, I have a figure of a man made of zinc in my hands. Let's dress him up.

Experience number 5. Description:

The participant of the evening lowers the figurine into a 10% lead acetate solution. The figurine is covered with a fluffy layer of lead crystals, reminiscent of fur clothing.

The essence of the experiment is that a more active metal displaces a less active metal from salt solutions.

Guys, is it possible to burn sugar without the help of fire? Let's check!

Experience number 6. Description:

The participant of the evening pours into a glass placed on a saucer, powdered sugar(30 g), pour 26 ml of concentrated sulfuric acid into the same place and stir the mixture with a glass rod. After 1-1.5 minutes, the mixture in the glass darkens, swells and rises above the edges of the glass in the form of a loose mass.

The essence of the experiment is that sulfuric acid removes water from sugar molecules, oxidizes carbon into carbon dioxide, and at the same time sulfur dioxide is formed. The released gases push the mass out of the glass.

What methods of making fire do you know?

Examples are given from the audience.

Let's try to do without these funds.

Experience number 7. Description:

A participant in the evening pours potassium permanganate (6 g) ground into powder on a piece of tin (or a tile) and drops glycerin on it from a pipette. After a while, a fire appears.

The essence of the experiment is that as a result of the reaction, atomic oxygen is released and glycerol ignites.

Other participant of the evening:

I will also get fire without matches, only in a different way.

Experience number 8. Description:

A participant in the evening sprinkles a small amount of potassium permanganate crystals on a brick and drips concentrated sulfuric acid on it. Around this mixture, he folds thin chips in the form of a fire, but so that they do not touch the mixture. Then he wets a small piece of cotton wool with alcohol and, holding his hand over the fire, squeezes a few drops of alcohol out of the cotton so that they fall on the mixture. The fire instantly lights up.

The essence of the experience is the vigorous oxidation of alcohol by oxygen, which is released during the interaction of sulfuric acid with potassium permanganate. The heat released during this reaction ignites the fire.

And now amazing lights!

Experience number 9. Description:

The participant of the evening puts cotton swabs moistened with ethyl alcohol into porcelain cups. On the surface of the tampons, he pours the following salts: sodium chloride, strontium nitrate (or lithium nitrate), potassium chloride, barium nitrate (or boric acid). On a piece of glass, the participant prepares a mixture (slurry) of potassium permanganate and concentrated sulfuric acid. He takes some of this mass with a glass rod and touches the surface of the tampons. Tampons flash and burn different colors: yellow, red, purple, green.

The essence of the experience is that alkali and alkaline earth metal ions color the flame in different colors.

Dear children, I am so tired and hungry that I ask you to allow me to eat a little.

Experience number 10. Description:

The host addresses the participant of the evening:

Give me some tea and biscuits, please.

The participant of the evening gives the host a glass of tea and a white cracker.

The host moistens the cracker in tea - the cracker turns blue.

Leading :

Disgrace, you almost poisoned me!

Participant of the evening:

Excuse me, I must have mixed up the glasses.

The essence of the experiment - in the glass was a solution of iodine. The starch in the bread turned blue.

Guys, I received a letter, but there was a blank sheet of paper in the envelope. Who can help me find out what's wrong?

Experience number 11. Description:

A student from the audience (prepared in advance) touches a smoldering splinter to a pencil mark on a sheet of paper. The paper along the line of the drawing slowly burns out and the light, moving along the contour of the image, outlines it (the drawing can be arbitrary).

The essence of the experience is that the paper burns due to the oxygen of the saltpeter crystallized in its thickness.

Note: a drawing is preliminarily applied to a sheet of paper with a strong solution of potassium nitrate. It must be applied in one continuous line without intersections. From the outline of the drawing with the same solution, draw a line to the edge of the paper, marking its end with a pencil. When the paper dries, the pattern will become invisible.

Well, now, guys, let's move on to the second part of our evening. Chemical games!

III. Team games.

Participants of the evening are invited to break into groups. Each group takes part in the proposed game.

Game number 1. Chemical lotto.

Formulas are written on cards, graphed as in a regular loto. chemical substances, and on cardboard squares - the names of these substances. The group members are given cards, and one of them pulls out the squares and names the substances. The winner is the member of the group who first closes all the fields of the card.

Game number 2. Chemical quiz.

A rope is stretched between the backs of two chairs. Sweets are tied to it on strings, to which pieces of paper with questions are attached. Group members take turns cutting candy with scissors. The player becomes the owner of the candy after answering the question attached to it.

The group members form a circle. They have chemical symbols and numbers in their hands. Two of the players are in the middle of the circle. On command, they make up the chemical formula of substances from the signs and numbers held by the other players. The participant who completes the formula the fastest wins.

The group members are divided into two teams. They are given cards with chemical formulas and numbers. They must write a chemical equation. The team that completes the equation first wins.

The evening ends with the presentation of prizes to the most active participants.

Helpful Hints

Children are always trying to find out something new every day and they always have a lot of questions.

They can explain some phenomena, or you can show how this or that thing, this or that phenomenon works.

In these experiments, children not only learn something new, but also learn create differentcrafts with which they can play further.

1. Experiments for children: lemon volcano

You will need:

2 lemons (for 1 volcano)

Baking soda

Food coloring or watercolors

Dishwashing liquid

Wooden stick or spoon (optional)

1. Cut off the bottom of the lemon so that it can be placed on flat surface.

2. On the reverse side, cut a piece of lemon as shown in the image.

* You can cut half a lemon and make an open volcano.

3. Take the second lemon, cut it in half and squeeze the juice out of it into a cup. This will be the backup lemon juice.

4. Place the first lemon (with the part cut out) on the tray and spoon "remember" the lemon inside to squeeze out some of the juice. It is important that the juice is inside the lemon.

5. Add food coloring or watercolor to the inside of the lemon, but do not stir.

6. Pour dishwashing liquid inside the lemon.

7. Add a full spoonful to the lemon baking soda. The reaction will start. With a stick or spoon, you can stir everything inside the lemon - the volcano will begin to foam.

8. To make the reaction last longer, you can gradually add more soda, dyes, soap and reserve lemon juice.

2. Home experiments for children: electric eels from chewing worms

You will need:

2 glasses

small capacity

4-6 chewable worms

3 tablespoons of baking soda

1/2 spoon of vinegar

1 cup water

Scissors, kitchen or clerical knife.

1. With scissors or a knife, cut lengthwise (just lengthwise - this will not be easy, but be patient) of each worm into 4 (or more) parts.

* The smaller the piece, the better.

* If scissors don't want to cut properly, try washing them with soap and water.

2. Mix water and baking soda in a glass.

3. Add pieces of worms to the solution of water and soda and stir.

4. Leave the worms in the solution for 10-15 minutes.

5. Using a fork, transfer the worm pieces to a small plate.

6. Pour half a spoon of vinegar into an empty glass and start putting worms in it one by one.

* The experiment can be repeated if the worms are washed with plain water. After a few attempts, your worms will begin to dissolve, and then you will have to cut a new batch.

3. Experiments and experiments: a rainbow on paper or how light is reflected on a flat surface

You will need:

bowl of water

Clear nail polish

Small pieces of black paper.

1. Add 1-2 drops to a bowl of water clear varnish for nails. See how the varnish disperses through the water.

2. Quickly (after 10 seconds) dip a piece of black paper into the bowl. Take it out and let it dry on a paper towel.

3. After the paper has dried (it happens quickly) start turning the paper and look at the rainbow that is displayed on it.

* To better see the rainbow on paper, look at it under the sun's rays.

4. Experiments at home: a rain cloud in a jar

When small drops of water accumulate in a cloud, they become heavier and heavier. As a result, they will reach such a weight that they can no longer remain in the air and will begin to fall to the ground - this is how rain appears.

This phenomenon can be shown to children with simple materials.

You will need:

Shaving foam

Food coloring.

1. Fill the jar with water.

2. Apply shaving foam on top - it will be a cloud.

3. Let the child begin to drip food coloring onto the "cloud" until it starts to "rain" - drops of food coloring begin to fall to the bottom of the jar.

During the experiment, explain this phenomenon to the child.

You will need:

warm water

Sunflower oil

4 food coloring

1. Fill the jar 3/4 full with warm water.

2. Take a bowl and mix 3-4 tablespoons of oil and a few drops of food coloring in it. AT this example 1 drop of each of 4 dyes was used - red, yellow, blue and green.

3. Stir the dyes and oil with a fork.

4. Carefully pour the mixture into a jar of warm water.

5. Watch what happens - the food coloring will begin to slowly sink through the oil into the water, after which each drop will begin to disperse and mix with other drops.

* Food coloring dissolves in water, but not in oil, because. The density of oil is less than water (which is why it "floats" on water). A drop of dye is heavier than oil, so it will begin to sink until it reaches the water, where it begins to disperse and look like a small firework.

6. Interesting experiences: ina bowl in which colors merge

You will need:

- a printout of the wheel (or you can cut out your own wheel and draw all the colors of the rainbow on it)

Elastic band or thick thread

Glue stick

Scissors

A skewer or screwdriver (to make holes in the paper wheel).

1. Choose and print the two templates you want to use.

2. Take a piece of cardboard and use a glue stick to glue one template to the cardboard.

3. Cut out the glued circle from the cardboard.

4. Glue the second template to the back of the cardboard circle.

5. Use a skewer or screwdriver to make two holes in the circle.

6. Pass the thread through the holes and tie the ends into a knot.

Now you can spin your spinning top and watch how the colors merge on the circles.

7. Experiments for children at home: jellyfish in a jar

You will need:

Small transparent plastic bag

Transparent plastic bottle

Food coloring

Scissors.

1. Lay the plastic bag on a flat surface and smooth it out.

2. Cut off the bottom and handles of the bag.

3. Cut the bag lengthwise on the right and left so that you have two sheets of polyethylene. You will need one sheet.

4. Find a center polyethylene sheet and fold it like a balloon to make a jellyfish head. Tie the thread around the "neck" of the jellyfish, but not too tight - you need to leave a small hole through which to pour water into the head of the jellyfish.

5. There is a head, now let's move on to the tentacles. Make cuts in the sheet - from the bottom to the head. You need about 8-10 tentacles.

6. Cut each tentacle into 3-4 smaller pieces.

7. Pour some water into the jellyfish's head, leaving room for air so the jellyfish can "float" in the bottle.

8. Fill the bottle with water and put your jellyfish in it.

9. Drop a couple of drops of blue or green food coloring.

* Close the lid tightly so that water does not spill out.

* Have the children turn the bottle over and watch the jellyfish swim in it.

8. Chemical experiments: magic crystals in a glass

You will need:

Glass cup or bowl

plastic bowl

1 cup Epsom salt (magnesium sulfate) - used in bath salts

1 cup hot water

Food coloring.

1. Pour Epsom salt into a bowl and add hot water. You can add a couple of drops of food coloring to the bowl.

2. Stir the contents of the bowl for 1-2 minutes. Most of the salt granules should dissolve.

3. Pour the solution into a glass or glass and place it in the freezer for 10-15 minutes. Don't worry, the solution isn't hot enough to crack the glass.

4. After freezing, move the solution to the main compartment of the refrigerator, preferably on top shelf and leave overnight.

The growth of crystals will be noticeable only after a few hours, but it is better to wait out the night.

This is what the crystals look like the next day. Remember that crystals are very fragile. If you touch them, they are most likely to break or crumble immediately.

9. Experiments for children (video): soap cube

10. Chemical experiments for children (video): how to make a lava lamp with your own hands

Who loved at school laboratory works in chemistry? It is interesting, after all, it was to mix something with something and get a new substance. True, it didn’t always work out the way it was described in the textbook, but no one suffered about this, did they? The main thing is that something happens, and we saw it right in front of us.

If in real life if you are not a chemist and do not face much more complex experiments every day at work, then these experiments that can be carried out at home will definitely amuse you, at least.

lava lamp

For experience you need:
– Transparent bottle or vase
— Water
- Sunflower oil
- Food coloring
- Several effervescent tablets "Suprastin"

Mix water with food coloring, pour sunflower oil. You don't need to mix, and you won't be able to. When a clear line between water and oil is visible, we throw a couple of Suprastin tablets into the container. Watching lava flows.

Because oil is less dense than water, it stays on the surface, and the effervescent tablet creates bubbles that carry water to the surface.

Elephant Toothpaste

For experience you need:
- Bottle
- small cup
— Water
- dish detergent or liquid soap
- Hydrogen peroxide
- Fast acting nutritional yeast
- Food coloring

Mix liquid soap, hydrogen peroxide and food coloring in a bottle. In a separate cup, dilute the yeast with water and pour the resulting mixture into a bottle. We look at the eruption.

Yeast releases oxygen, which reacts with hydrogen and is pushed out. Due to the soap suds, a dense mass erupts from the bottle.

Hot Ice

For experience you need:
- container for heating
- Clear glass cup
- Plate
- 200 g baking soda
- 200 ml of acetic acid or 150 ml of its concentrate
- crystallized salt

We mix acetic acid and soda in a saucepan, wait until the mixture stops sizzling. Turn on the stove and boil excess moisture until an oily film appears on the surface. The resulting solution is poured into a clean container and cooled to room temperature. Then add a crystal of soda and watch how the water “freezes” and the container becomes hot.

Heated and mixed vinegar and soda form sodium acetate, which, when melted, becomes aqueous solution sodium acetate. When salt is added to it, it begins to crystallize and release heat.

rainbow in milk

For experience you need:
- Milk
- Plate
- Liquid food coloring in several colors
- cotton swab
— Detergent

Pour milk into a plate, drip dyes in several places. Wet a cotton swab in detergent, dip it into a bowl of milk. Let's see the rainbow.

In the liquid part there is a suspension of droplets of fat, which, in contact with detergent split and rush from the inserted stick in all directions. A regular circle is formed due to surface tension.

Smoke without fire

For experience you need:
– Hydroperite
— Analgin
- Mortar and pestle (can be replaced with a ceramic cup and spoon)

The experiment is best done in a well-ventilated area.
We grind hydroperite tablets to a powder, we do the same with analgin. We mix the resulting powders, wait a bit, see what happens.

During the reaction, hydrogen sulfide, water and oxygen are formed. This leads to partial hydrolysis with the elimination of methylamine, which interacts with hydrogen sulfide, a suspension of its small crystals which resembles smoke.

pharaoh snake

For experience you need:
- Calcium gluconate
- Dry fuel
- Matches or lighter

We put several tablets of calcium gluconate on dry fuel, set fire to it. Let's look at the snakes.

Calcium gluconate decomposes when heated, which leads to an increase in the volume of the mixture.

non-newtonian fluid

For experience you need:

- mixing bowl
- 200 g corn starch
- 400 ml of water

Gradually add water to the starch and stir. Try to make the mixture homogeneous. Now try to roll the ball out of the resulting mass and hold it.

The so-called non-Newtonian fluid during rapid interaction behaves as solid, and when slow - like a liquid.