Chemistry experiments. Interesting chemistry experiments you can do at home

My personal experience in teaching chemistry has shown that a science like chemistry is very difficult to study without any prior knowledge and practice. Schoolchildren very often neglect this subject. I personally observed how an 8th grade student, when he heard the word “chemistry,” began to wince, as if he had eaten a lemon.

Later it turned out that due to dislike and misunderstanding of the subject, he skipped school secretly from his parents. Certainly, school program is designed in such a way that the teacher must give a lot of theory in the first chemistry lessons. Practice seems to fade into the background precisely at the moment when the student cannot yet independently realize whether he needs this subject in the future. This is primarily due to the laboratory equipment of schools. IN big cities Currently, the situation with reagents and instruments is better. As for the province, just like 10 years ago and now, many schools do not have the opportunity to conduct laboratory classes. But the process of studying and becoming interested in chemistry, as well as other natural sciences, usually begins with experiments. And this is no coincidence. Many famous chemists, such as Lomonosov, Mendeleev, Paracelsus, Robert Boyle, Pierre Curie and Marie Sklodowska-Curie (schoolchildren also study all of these researchers in physics lessons) began experimenting from childhood. The great discoveries of these great people were made precisely in home chemical laboratories, since studying chemistry in institutes was available only to people of means.

And, of course, the most important thing is to interest the child and convey to him that chemistry surrounds us everywhere, so the process of studying it can be very exciting. This is where your family will come to the rescue chemical experiments. By observing such experiments, one can further look for an explanation of why things happen this way and not otherwise. And when a young researcher encounters similar concepts in school lessons, the teacher’s explanations will be more understandable to him, since he will already have his own experience in conducting chemical experiments at home and the knowledge gained.

It is very important to start learning science with common observations and real-life examples that you think will be most successful for your child. Here are some of them. Water is a chemical substance consisting of two elements, as well as gases dissolved in it. Man also contains water. It is known that where there is no water, there is no life. A person can live without food for about a month, but without water - only a few days.

River sand is nothing more than silicon oxide, and is also the main raw material for glass production.

A person himself does not suspect it and carries out chemical reactions every second. The air we breathe is a mixture of gases - chemicals. During exhalation, another complex substance is released - carbon dioxide. We can say that we ourselves are a chemical laboratory. You can explain to your child that washing hands with soap is also a chemical process of water and soap.

An older child who, for example, has already started studying chemistry at school, can be explained that almost all elements can be found in the human body periodic table D. I. Mendeleev. Not only are all chemical elements present in a living organism, but each of them performs some biological function.

Chemistry also includes medicines, without which many people nowadays cannot live a day.

Plants also contain the chemical chlorophyll, which gives leaves their green color.

Cooking is a complex chemical process. Here is an example of how dough rises when yeast is added.

One of the options for getting a child interested in chemistry is to take an individual outstanding researcher and read the story of his life or watch an educational film about him (films about D.I. Mendeleev, Paracelsus, M.V. Lomonosov, Butlerov are now available).

Many people believe that real chemistry is harmful substances, experimenting with them is dangerous, especially at home. There are many very exciting experiences that you can do with your child without harming your health. And these home chemical experiments will be no less exciting and instructive than those that come with explosions, acrid odors and clouds of smoke.

Some parents are also afraid to conduct chemical experiments at home because of their complexity or lack of necessary equipment and reagents. It turns out that you can get by with improvised means and those substances that every housewife has in her kitchen. You can buy them at your local hardware store or pharmacy. Test tubes for conducting home chemical experiments can be replaced with bottles of tablets. To store reagents, you can use glass jars, for example, baby food or mayonnaise.

It is worth remembering that the container with reagents must have a label with the inscription and be tightly closed. Sometimes the test tubes need to be heated. In order not to hold it in your hands when it heats up and not get burned, you can build such a device using a clothespin or a piece of wire.

It is also necessary to allocate several steel and wooden spoons for mixing.

You can make a stand for holding test tubes yourself by drilling through holes in the block.

To filter the resulting substances you will need a paper filter. It is very easy to make according to the diagram given here.

For children who do not yet go to school or are in elementary school, performing chemical experiments at home with their parents will be a kind of game. Most likely, such a young researcher will not yet be able to explain some individual laws and reactions. However, perhaps it is precisely this empirical method of discovering the surrounding world, nature, man, and plants through experiments that will lay the foundation for the study of natural sciences in the future. You can even organize some kind of competitions in the family to see who has the most successful experience and then demonstrate them at family holidays.

Regardless of your child's age or ability to read and write, I recommend keeping a laboratory journal in which you can record experiments or sketch. A real chemist always writes down a work plan, a list of reagents, sketches the instruments and describes the progress of the work.

When you and your child first begin to study this science of substances and conduct home chemical experiments, the first thing you need to remember is safety.

To do this you need to follow following rules security:

2. It is better to allocate a separate table for conducting chemical experiments at home. If you do not have a separate table at home, then it is better to conduct experiments on a steel or iron tray or pallet.

3. You need to get thin and thick gloves (they are sold at a pharmacy or hardware store).

4. For chemical experiments, it is best to buy a lab coat, but you can also use a thick apron instead of a coat.

5. Laboratory glassware should not be further used for food.

6. In home chemical experiments there should be no cruelty to animals or disruption of the ecological system. Acidic chemical wastes must be neutralized with soda, and alkaline ones must be neutralized. acetic acid.

7. If you want to check the smell of a gas, liquid or reagent, never bring the container directly to your face, but, holding it at some distance, direct the air above the container towards you by waving your hand and at the same time smell the air.

8. Always use small quantities of reagents in home experiments. Avoid leaving reagents in a container without an appropriate inscription (label) on the bottle, from which it should be clear what is in the bottle.

You should start learning chemistry with simple chemical experiments at home, allowing your child to master the basic concepts. A series of experiments 1-3 allow you to get acquainted with the basic aggregative states of substances and the properties of water. To begin with, you can show your preschooler how sugar and salt dissolve in water, accompanying this with an explanation that water is a universal solvent and is a liquid. Sugar or salt are solids that dissolve in liquid.

Experience No. 1 “Because - without water and neither here nor there”

Water is a liquid chemical substance consisting of two elements as well as gases dissolved in it. Man also contains water. It is known that where there is no water, there is no life. A person can live without food for about a month, and without water - only a few days.

Reagents and equipment: 2 test tubes, soda, citric acid, water

Experiment: Take two test tubes. Pour into them equal quantities soda and citric acid. Then pour water into one of the test tubes, but not into the other. In a test tube in which water was poured, carbon dioxide began to be released. In a test tube without water - nothing has changed

Discussion: This experiment explains the fact that without water many reactions and processes in living organisms are impossible, and water also accelerates many chemical reactions. It can be explained to schoolchildren that an exchange reaction occurred, as a result of which carbon dioxide was released.

Experiment No. 2 “What is dissolved in tap water”

Reagents and equipment: transparent glass, tap water

Experiment: Pour tap water into a transparent glass and leave it in a warm place for an hour. After an hour, you will see settled bubbles on the walls of the glass.

Discussion: Bubbles are nothing more than gases dissolved in water. Gases dissolve better in cold water. As soon as the water becomes warm, the gases stop dissolving and settle on the walls. Such a home chemical experiment also allows you to introduce your child to the gaseous state of matter.

Experiment No. 3 “What is dissolved in mineral water or water is a universal solvent”

Reagents and equipment: test tube, mineral water, candle, magnifying glass

Experiment: Pour mineral water into a test tube and slowly evaporate it over a candle flame (the experiment can be done on the stove in a saucepan, but the crystals will be less visible). As the water evaporates, small crystals will remain on the walls of the test tube, all of them of different shapes.

Discussion: Crystals are salts dissolved in mineral water. They have different shape and size, since each crystal has its own chemical formula. With a child who has already started studying chemistry at school, you can read the label on mineral water, where its composition is indicated, and write the formulas of the compounds contained in the mineral water.

Experiment No. 4 “Filtering water mixed with sand”

Reagents and equipment: 2 test tubes, funnel, paper filter, water, river sand

Experiment: Pour water into a test tube and add a little river sand there, mix. Then, according to the scheme described above, make a filter out of paper. Insert a dry, clean test tube into the rack. Slowly pour the sand and water mixture through a funnel with a paper filter. The river sand will remain on the filter, and you will get clean water in the test tube.

Discussion: Chemical experiment allows us to show that there are substances that do not dissolve in water, for example, river sand. The experience also introduces one of the methods for purifying mixtures of substances from impurities. Here you can introduce the concepts of pure substances and mixtures, which are given in the 8th grade chemistry textbook. In this case, the mixture is sand and water, pure substance- filtrate, river sand is sediment.

The filtration process (described in grade 8) is used here to separate a mixture of water and sand. To diversify the study of this process, you can delve a little deeper into the history of drinking water purification.

Filtration processes were used as early as the 8th and 7th centuries BC. in the state of Urartu (now the territory of Armenia) to purify drinking water. Its residents carried out the construction plumbing system using filters. We used as filters thick fabric and charcoal. Similar systems of intertwined drainpipes, clay channels, equipped with filters were also on the territory of the ancient Nile by the ancient Egyptians, Greeks and Romans. Water was passed through such a filter several times, ultimately many times, ultimately achieving best quality water.

One of the most interesting experiments is growing crystals. The experiment is very visual and gives an idea of ​​many chemical and physical concepts.

Experiment No. 5 “Growing sugar crystals”

Reagents and equipment: two glasses of water; sugar - five glasses; wooden skewers; thin paper; pot; transparent cups; food coloring (the proportions of sugar and water can be reduced).

Experiment: The experiment should begin with the preparation of sugar syrup. Take a saucepan, pour 2 cups of water and 2.5 cups of sugar into it. Place over medium heat and, stirring, dissolve all the sugar. Pour the remaining 2.5 cups of sugar into the resulting syrup and cook until completely dissolved.

Now let's prepare the crystal seeds - rods. Sprinkle a small amount of sugar on a piece of paper, then dip the stick in the resulting syrup and roll it in sugar.

We take the pieces of paper and poke a hole in the middle with a skewer so that the paper fits tightly to the skewer.

Then pour the hot syrup into transparent glasses (it is important that the glasses are transparent - this way the process of crystal ripening will be more exciting and visual). The syrup must be hot, otherwise the crystals will not grow.

You can make colored sugar crystals. To do this, add a little food coloring to the resulting hot syrup and stir it.

The crystals will grow in different ways, some quickly and some may take longer. At the end of the experiment, the child can eat the resulting candies if he is not allergic to sweets.

If you do not have wooden skewers, then the experiment can be carried out with ordinary threads.

Discussion: A crystal is a solid state of matter. It has a certain shape and a certain number of faces due to the arrangement of its atoms. Substances whose atoms are arranged regularly so that they form a regular three-dimensional lattice, called crystalline, are considered crystalline. Crystals of a number of chemical elements and their compounds have remarkable mechanical, electrical, magnetic and optical properties. For example, diamond is a natural crystal and the hardest and rarest mineral. Due to its exceptional hardness, diamond plays a huge role in technology. Diamond saws are used to cut stones. There are three ways to form crystals: crystallization from a melt, from a solution and from the gas phase. An example of crystallization from a melt is the formation of ice from water (after all, water is molten ice). An example of crystallization from a solution in nature is the precipitation of hundreds of millions of tons of salt from sea ​​water. In this case, when growing crystals at home, we are dealing with the most common method of artificial growth - crystallization from solution. Sugar crystals grow from a saturated solution with the slow evaporation of the solvent - water or with a slow decrease in temperature.

The following experiment allows you to obtain at home one of the most useful crystalline products for humans - crystalline iodine. Before conducting the experiment, I advise you to watch the short film “The Life of Wonderful Ideas” with your child. Smart iodine." The film gives an idea of ​​the benefits of iodine and the unusual story of its discovery, which the young researcher will remember for a long time. And it is interesting because the discoverer of iodine was an ordinary cat.

During the Napoleonic Wars, the French scientist Bernard Courtois noticed that the products obtained from the ash of seaweed that washed up on the shores of France contained some substance that corroded iron and copper vessels. But neither Courtois himself nor his assistants knew how to isolate this substance from algae ash. An accident helped speed up the discovery.

At his small saltpeter production plant in Dijon, Courtois planned to conduct several experiments. There were vessels on the table, one of which contained a tincture of seaweed in alcohol, and the other a mixture of sulfuric acid and iron. His favorite cat was sitting on the scientist’s shoulders.

There was a knock on the door, and the frightened cat jumped and ran away, sweeping away the flasks on the table with her tail. The vessels broke, the contents were mixed, and a violent chemical reaction suddenly began. When a small cloud of vapors and gases settled, the surprised scientist saw some kind of crystalline coating on objects and debris. Courtois began to investigate it. The crystals of this previously unknown substance were called “iodine”.

Thus, a new element was discovered, and Bernard Courtois’s domestic cat went down in history.

Experiment No. 6 “Obtaining iodine crystals”

Reagents and equipment: tincture of pharmaceutical iodine, water, glass or cylinder, napkin.

Experiment: Mix water with iodine tincture in the proportion: 10 ml iodine and 10 ml water. And put everything in the refrigerator for 3 hours. During the cooling process, iodine will precipitate at the bottom of the glass. Drain the liquid, remove the iodine precipitate and place it on a napkin. Squeeze with napkins until the iodine begins to crumble.

Discussion: This chemical experiment is called extraction or extraction of one component from another. In this case, water extracts iodine from the alcohol solution. Thus, the young researcher will repeat the experiment of Courtois the cat without smoke and breaking of dishes.

Your child will already learn about the benefits of iodine for disinfecting wounds from the film. Thus, you will show that there is an inextricable connection between chemistry and medicine. However, it turns out that iodine can be used as an indicator or analyzer of the content of another useful substance - starch. The following experiment will introduce the young experimenter to a separate, very useful chemistry - analytical.

Experiment No. 7 “Iodine-indicator of starch content”

Reagents and equipment: fresh potatoes, pieces of banana, apple, bread, a glass of diluted starch, a glass of diluted iodine, a pipette.

Experiment: We cut the potatoes into two parts and drip diluted iodine on it - the potatoes turn blue. Then drop a few drops of iodine into a glass with diluted starch. The liquid also turns blue.

Using a pipette, drop iodine dissolved in water onto an apple, banana, bread, one at a time.

We observe:

The apple did not turn blue at all. Banana - slightly blue. The bread turned very blue. This part of the experiment shows the presence of starch in various foods.

Discussion: Starch reacts with iodine to give a blue color. This property allows us to detect the presence of starch in various products. Thus, iodine is like an indicator or analyzer of starch content.

As you know, starch can be converted into sugar; if you take an unripe apple and drop iodine, it will turn blue, since the apple is not yet ripe. As soon as the apple is ripe, all the starch contained will turn into sugar and the apple, when treated with iodine, will not turn blue at all.

The following experience will be useful for children who have already started studying chemistry at school. It introduces concepts such as chemical reaction, compound reaction, and qualitative reaction.

Experiment No. 8 “Flame coloring or compound reaction”

Reagents and equipment: tweezers, table salt, alcohol lamp

Experiment: Using tweezers, take a few crystals of coarse table salt. Let's hold them over the flame of the burner. The flame will turn yellow.

Discussion: This experiment allows for a combustion chemical reaction, which is an example of a compound reaction. Due to the presence of sodium in table salt, during combustion it reacts with oxygen. As a result, a new substance is formed - sodium oxide. The appearance of a yellow flame indicates that the reaction has completed. Such reactions are qualitative reactions to compounds containing sodium, that is, they can be used to determine whether a substance contains sodium or not.

This manual increases interest in the subject, develops cognitive, thinking, and research activities. Students analyze, compare, study and summarize the material, receive new information and practical skills. Students can conduct some experiments on their own at home, but most of them can be done in a chemistry class under the guidance of a teacher.

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village Novomikhailovsky

Municipal entity

Tuapse district

"Chemical reactions around us"

Teacher:

Kozlenko

Alevtina Viktorovna

2015

« Vulcan" on the table.Ammonium dichromate mixed with magnesium metal is poured into the crucible (the mound in the center is moistened with alcohol). They light the “volcano” with a burning torch. The reaction is exothermic, proceeds violently, along with nitrogen, hot particles of chromium (III) oxide and

burning magnesium. If you turn off the light, you get the impression of an erupting volcano, from the crater of which hot masses pour out:

(NH 4 ) 2 Cr 2 O 7 = Cr 2 O 3 +4H 2 O + N 2; 2Mg + O 2 = 2MgO.

"Star Rain".Pour three tablespoons of potassium permanganate, carbon powder and reduced iron powder onto a sheet of clean paper, mixing thoroughly. The resulting mixture is poured into an iron crucible, which is secured in the ring of a tripod and heated with the flame of an alcohol lamp. The reaction begins and the mixture is ejected

in the form of many sparks giving the impression of “rain of fire”.

Fireworks in the middle of the liquid. 5 ml of concentrated sulfuric acid is poured into the cylinder and 5 ml of ethyl alcohol is carefully poured along the cylinder wall, then several crystals of potassium permanganate are thrown in. Sparks appear at the boundary between the two liquids, accompanied by crackling sounds. Alcohol ignites when oxygen appears, which is formed when potassium permanganate reacts with sulfuric acid.

"Green Fire" . Boric acid and ethyl alcohol form an ester:

H 3 VO 3 + 3C 2 H 5 OH = B(OS 2 H 5 ) + 3H 2 O

1 g of boric acid is poured into a porcelain cup, 10 ml of alcohol and 1 ml of sulfuric acid are added. The mixture is stirred with a glass rod and set on fire. Ether vapors burn with a green flame.

Water lights paper. In a porcelain cup, mix sodium peroxide with small pieces of filter paper. A few drops of water are dripped onto the prepared mixture. The paper is flammable.

Na 2 O 2 + 2H 2 O = H 2 O 2 + 2NaOH

2H 2 O 2 = 2H 2 O + O 2 |

Multi-colored flames.Different flame colors can be shown when chlorides are burned in alcohol. To do this, take clean porcelain cups with 2-3 ml of alcohol. Add 0.2-0.5 g of finely ground chlorides to the alcohol. The mixture is set on fire. In each cup, the color of the flame is characteristic of the cation that is present in the salt: lithium - crimson, sodium - yellow, potassium - violet, rubidium and cesium - pink-violet, calcium - brick red, barium - yellowish-green, strontium - raspberry, etc.

Magic wands.Three beakers are filled to approximately 3/4 volume with solutions of litmus, methyl orange and phenolphthalein.

Solutions of hydrochloric acid and sodium hydroxide are prepared in other glasses. A glass tube is used to draw up a solution of sodium hydroxide. Mix the liquid in all glasses with this tube, quietly pouring out a small amount of solution each time. The color of the liquid in the glasses will change. Then draw acid into the second tube in this way.and mix liquids in glasses with it. The color of the indicators will change dramatically again.

Magic wand.For the experiment, a pre-prepared slurry of potassium permanganate and concentrated sulfuric acid is placed in porcelain cups. A glass rod is immersed in a freshly prepared oxidizing mixture. Quickly bring the stick to the wet wick of an alcohol lamp or cotton wool soaked in alcohol, the wick ignites. (It is prohibited to re-introduce a stick moistened with alcohol into the pulp.)

2KMnO 4 + H 2 SO 4 = Mn 2 O 7 + K 2 SO 4 + H 2 O

6Mn 2 O 7 + 5C 2 H 5 OH +12H 2 SO 4 = l2MnSO 4 + 10СО 2 + 27Н 2 О

A reaction takes place, releasing a large amount of heat, and the alcohol ignites.

Self-igniting liquid.Place 0.5 g of potassium permanganate crystals lightly ground in a mortar into a porcelain cup, and then apply 3-4 drops of glycerin from a pipette. After some time, glycerin ignites:

14KMnO 4 +3C 3 H 6 (OH) 3 = 14MnO 2 +9CO 2 +5H 2 O+14KOH

Combustion of various substancesin molten crystals.

Three test tubes are filled 1/3 full with white crystals of potassium nitrate. All three test tubes are fixed vertically in a stand and simultaneously heated with three alcohol lamps. When the crystals melt,A piece of heated charcoal is lowered into the first test tube, a piece of heated sulfur into the second, and a little lit red phosphorus into the third. In the first test tube, the coal burns, “jumping” as it does so. In the second test tube, a piece of sulfur burns with a bright flame. In the third test tube, red phosphorus burns, releasing such an amount of heat that the test tube melts.

Water is a catalyst.Mix carefully on a glass plate

4 g of powdered iodine and 2 g of zinc dust. No reaction occurs. A few drops of water are dripped onto the mixture. An exothermic reaction begins, releasing violet iodine vapor, which reacts with zinc. The experiment is carried out under traction.

Self-ignition of paraffin.Fill 1/3 of the test tube with pieces of paraffin and heat it to its boiling point. Pour boiling paraffin from a test tube, from a height of about 20 cm, in a thin stream. Paraffin flares up and burns with a bright flame. (Paraffin cannot ignite in a test tube, since there is no air circulation. When paraffin is poured in a thin stream, air access to it is facilitated. And since the temperature of the molten paraffin is higher than its ignition temperature, it flares up.)

Municipal autonomous educational institution

Secondary school No. 35

village Novomikhailovsky

Municipal entity

Tuapse district

Entertaining experiments on the topic

"Chemistry in our house"

Teacher:

Kozlenko

Alevtina Viktorovna

2015

Smoke without fire. A few drops of concentrated hydrochloric acid are poured into one cleanly washed cylinder, and an ammonia solution is poured into the other. Both cylinders are covered with lids and placed at some distance from each other. Before the experiment they show that the cylinders are let. During the demonstration, a cylinder with hydrochloric acid(on the walls) are turned upside down and placed on the lid of the ammonia cylinder. The lid is removed: white smoke is formed.

"Golden" knife. Add 1 ml of sulfuric acid to 200 ml of saturated solution of copper sulfate. Take a knife cleaned with sandpaper. Dip the knife into the copper sulfate solution for a few seconds, remove it, rinse it and immediately wipe it dry with a towel. The knife becomes “golden”. It was covered with an even, shiny layer of copper.

Freezing of glass.Pour ammonium nitrate into a glass of water and place it on wet plywood, which freezes to the glass.

Colored solutions. Before the experiment, crystalline hydrates of copper, nickel, and cobalt salts are dehydrated. After adding water to them, colored solutions are formed. Anhydrous White powder copper salts form a solution blue color, green nickel-green salt powder, blue salt powder 4 cobalt - red.

Blood without a wound. To carry out the experiment, use 100 ml of a 3% solution of iron chloride FeCI 3 in 100 silt of 3% solution of potassium thiocyanate KCNS. To demonstrate the experience, a children's polyethylene sword is used. Call someone from the audience onto the stage. Use a cotton swab to wash your palm with FeCI solution. 3 , and a colorless KCNS solution is moistened onto the sword. Next, the sword is drawn across the palm: “blood” flows copiously onto the paper:

FeCl 3 + 3KCNS=Fe(CNS) 3 +3KCl

“Blood” is washed off from the palm with cotton wool moistened with a solution of sodium fluoride. They show the audience that there is no wound and the palm is completely clean.

Instant color “photography”.Yellow and red blood salts, interacting with salts of heavy metals, give different colors reaction products: yellow blood salt with iron (III) sulfate gives a blue color, with copper (II) salts - dark brown, with bismuth salts - yellow, with iron (II) salts - green. Using the above salt solutions, make a drawing on white paper and dry it. Since the solutions are colorless, the paper remains uncolored. To develop such drawings, a damp swab moistened with a solution of yellow blood salt is passed over the paper.

Turning liquid into jelly.100 g of sodium silicate solution is poured into a beaker and 5 ml of 24% hydrochloric acid solution is added. Stir the mixture of these solutions with a glass rod and hold the rod vertically in the solution. After 1-2 minutes, the rod no longer falls in the solution, because the liquid has thickened so much that it does not pour out of the glass.

Chemical vacuum in a bottle. Fill the flask with carbon dioxide. Pour a little concentrated solution of potassium hydroxide into it and close the opening of the bottle with a peeled hard-boiled egg, the surface of which is smeared with a thin layer of Vaseline. The egg gradually begins to be drawn into the bottle and, with the sharp sound of a shot, falls on its bottom.

(A vacuum was formed in the flask as a result of the reaction:

CO 2 + 2KON = K 2 CO 3 + H 2 O.

The outside air pressure pushes the egg.)

Fireproof handkerchief.The handkerchief is soaked in a sodium silicate solution, dried and folded. To demonstrate its non-flammability, it is moistened with alcohol and set on fire. The handkerchief must be held flat with crucible tongs. The alcohol burns, but the fabric impregnated with sodium silicate remains unharmed.

Sugar burns with fire.Take a piece of refined sugar with tongs and try to set it on fire - the sugar does not light up. If this piece is sprinkled with cigarette ashes and then set on fire with a match, the sugar lights up with a bright blue flame and burns quickly.

(The ash contains lithium compounds that act as a catalyst.)

Coal from sugar. Weigh out 30 g of powdered sugar and transfer it to a beaker. Add ~12 ml of concentrated sulfuric acid to the powdered sugar. Using a glass rod, stir the sugar and acid into a mushy mass. After some time, the mixture turns black and heats up, and soon a porous coal mass begins to crawl out of the glass.

Municipal autonomous educational institution

Secondary school No. 35

village Novomikhailovsky

Municipal entity

Tuapse district

Entertaining experiments on the topic

"Chemistry in Nature"

Teacher:

Kozlenko

Alevtina Viktorovna

2015

Mining "gold".Lead acetate is dissolved in one flask with hot water, and potassium iodide is dissolved in the other. Both solutions are poured into a large flask, the mixture is allowed to cool and display beautiful golden flakes floating in the solution.

Pb(CH 3 COO) 2 + 2KI = PbI 2 + 2CH3COOK

Mineral "chameleon".3 ml of a saturated solution of potassium permanganate and 1 ml of a 10% solution of potassium hydroxide are poured into a test tube.

While shaking, add 10-15 drops of sodium sulfite solution to the resulting mixture until a dark green color appears. When stirred, the color of the solution turns blue, then purple and finally crimson.

The appearance of a dark green color is due to the formation of potassium manganate

K 2 MnO 4:

2KMnO 4 + 2KOH + Na 2 SO 3 = 2K 2 MnO 4 + Na 2 SO 4 + H 2 O.

The change in the dark green color of the solution is explained by the decomposition of potassium manganate under the influence of atmospheric oxygen:

4K 2 MnO 4 + O 2 + 2H 2 O = 4KMnO 4 + 4KON.

Conversion of red phosphorus to white.A glass rod is lowered into a dry test tube and red phosphorus is added in the amount of half a pea. The bottom of the test tube is heated strongly. White smoke appears first. With further heating, yellowish droplets of white phosphorus appear on the cold inner walls of the test tube. It is also deposited on a glass rod. After heating the test tube stops, the glass rod is removed. White phosphorus on it ignites. Using the end of a glass rod, remove white phosphorus from the inner walls of the test tube. A second outbreak occurs in the air.

Only the teacher conducts the experiment.

Pharaoh's snakes. To conduct the experiment, prepare a salt - mercury (II) thiocyanate by mixing a concentrated solution of mercury (II) nitrate with a 10% solution of potassium thiocyanate. The precipitate is filtered, washed with water, and sticks are made 3-5 mm thick and 4 cm long. The sticks are dried on glass at room temperature. During the demonstration, the sticks are placed on a demonstration table and set on fire. As a result of the decomposition of mercury(II) thiocyanate, products are released that take the form of a writhing snake. Its volume is many times greater than the original volume of salt:

Hg(NO 3 ) 2 + 2KCNS = Нg(CNS) 2 + 2KNO 3

2Hg (CNS| 2 = 2HgS + CS 2 + C 3 N 4.

Dark gray "snake".Sand is poured into a crystallizer or onto a glass plate and soaked in alcohol. Make a hole in the center of the cone and place a mixture of 2 g of baking soda and 13 g of powdered sugar there. Alcohol is set on fire. Caxap turns into caramel, and soda decomposes, releasing carbon monoxide (IV). A thick dark gray “snake” crawls out of the sand. The longer the alcohol burns, the longer the “snake”.

"Chemical algae». A solution of silicate glue (sodium silicate) diluted with an equal volume of water is poured into a glass. Crystals of chlorides of calcium, manganese (II), cobalt (II), nickel (II) and other metals are thrown into the bottom of the glass. After some time, crystals of the corresponding sparingly soluble silicates begin to grow in the glass, resembling algae.

Burning snow. Together with the snow, 1-2 pieces of calcium carbide are placed in the jar. After this, a burning splinter is brought to the jar. The snow flares up and burns with a smoky flame. The reaction occurs between calcium carbide and water:

CaC 2 + 2H 2 O = Ca(OH) 2 + C 2 H 2

The gas released - acetylene burns:

2C 2 H 2 + 5O 2 = 4CO 2 + 2H 2 O.

"Buran" in a glass.Pour 5 g of benzoic acid into a 500 ml beaker and add a pine sprig. Cover the glass with a porcelain cup filled with cold water and heat it over an alcohol lamp. The acid first melts, then turns into steam, and the glass is filled with white “snow”, which covers the twig.

Secondary school No. 35

p. Novomikhailovsky

Municipal entity

Tuapse district

Entertaining experiments on the topic

"Chemistry in Agriculture"

Teacher:

Kozlenko

Alevtina Viktorovna

2015

Different ways to obtain “milk”.For the experiment, solutions are prepared: sodium chloride and silver nitrate; barium chloride and sodium sulfate; calcium chloride and sodium carbonate. Pour these solutions into separate glasses. In each of them “milk” is formed - insoluble white salts:

NaCI+ AgNO 3 = AgCI ↓ + NaNO 3 ;

Na 2 SO 4 + BaCI 2 = BaSO 4 ↓ + 2NaCI;

Na 2 CO 3 + CaCI 2 = CaCO 3 ↓+ 2NaCI.

Transforming milk into water.Excess hydrochloric acid is added to the white precipitate obtained by combining solutions of calcium chloride and sodium carbonate. The liquid boils and becomes colorless and

transparent:

CaCl 2 +Na 2 CO 3 = CaCO 3 ↓+2NaCl;

CaCO3↓ + 2HCI = CaCI 2 +H 2 O + CO 2.

Original egg. Drop into a glass jar containing a dilute solution of hydrochloric acid. egg. After 2-3 minutes, the egg is covered with gas bubbles and floats to the surface of the liquid. The gas bubbles break away and the egg sinks to the bottom again. So, diving and rising, the egg moves until the shell dissolves.

Municipal educational institution

Secondary school No. 35

p. Novomikhailovsky

municipality

Tuapse district

Extracurricular activity

"Interesting questions about chemistry"

Teacher:

Kozlenko

Alevtina Viktorovna

2015

Quiz.

1. Name the ten most common in earth's crust elements.

2. Which one chemical element discovered earlier on the Sun than on Earth?

3. What rare metal is found in some precious stones?

4. What is helium air?

5. What metals and alloys melt in hot water?

6. What refractory metals do you know?

7. What is heavy water?

8. Name the elements that make up human body.

9. Name the heaviest gas, liquid and solid.

10. How many elements are used in the manufacture of a car?

11. What chemical elements enter the plant from air, water, soil?

12. What salts of sulfuric and hydrochloric acids are used to protect plants from pests and diseases?

13. What molten metal can be used to freeze water?

14. Is it good for a person to drink clean water?

15. Who was the first to determine the quantitative chemical composition of water using methods of synthesis and analysis?

16 . Which gas is in a solid state at a temperature - 2>252 °C combines with liquid hydrogen explosion?

17. What element is the basis of the entire mineral world of the planet?

18. Which compound of chlorine and mercury is a strong poison?

19. The names of which elements are associated with radioactive processes?

Answers:

1. The most common elements in the earth’s crust are: oxygen, silicon, aluminum, iron, calcium, sodium, magnesium, potassium, hydrogen, titanium. These elements occupy approximately 96.4% of the mass of the earth's crust; only 3.5% of the mass of the earth's crust remains for all other elements.

2. Helium was first discovered on the Sun, and only a quarter of a century later it was found on Earth.

3. The metal beryllium is found in nature as a component of precious stones (beryl, aquamarine, alexandrite, etc.).

4. This is the name for artificial air, which contains approximately 20% oxygen and 80% helium.

5. The following metals melt in hot water: cesium (+28.5 °C), gallium (+ 29.75 °C), rubidium (+ 39 °C), potassium (+63 °C). Wood's alloy (50% Bi, 25% Pb, 12.5% ​​Sn, 12.5% ​​Cd) melts at +60.5°C.

6. The most refractory metals are: tungsten (3370°C), rhenium (3160°C), tantalum (3000°C), osmium (2700°C), molybdenum (2620°C), niobium (2415°C).

7. Heavy water is a compound of the hydrogen isotope deuterium with oxygen D 2 A. Heavy water is found in small quantities in ordinary water (1 part by weight per 5000 parts by weight).

8. The human body contains more than 20 elements: oxygen (65.04%), carbon (18.25%), hydrogen (10.05%), nitrogen (2.65%), calcium (1.4%) , phosphorus (0.84%), potassium (0.27%), chlorine (0.21%), sulfur (0.21%) and

etc.

9. Most heavy gas, taken under normal conditions, is tungsten hexafluoride WF 6 , the heaviest liquid is mercury, the heaviest solid is the metal osmium Os.

10. In the manufacture of a car, approximately 50 chemical elements are used, which are part of 250 different substances and materials.

11. Carbon, nitrogen, oxygen enter the plant from the air. Hydrogen and oxygen from water. All other elements enter the plant from the soil.

12. To protect plants from pests and diseases, copper and iron sulfates, barium and zinc chlorides are used.

13. You can freeze water with mercury; it melts at a temperature of 39 °C.

14. Chemists consider distilled water to be relatively pure water. But it is harmful to the body becauseit does not contain useful salts and gases. It flushes salts contained in the cell juice from the stomach cells.

15. The quantitative chemical composition of water was determined first by synthesis and then by analysis by Lavoisier.

16. Fluorine is a very strong oxidizing agent. In the solid state, it combines with liquid hydrogen at a temperature of -252 °C.

17. Silicon makes up 27.6% of the earth's crust and is the main element in the kingdom of minerals and rocks, which are exclusively composed of silicon compounds.

18. A strong poison is a compound of chlorine and mercury - sublimate. In medicine, sublimate is used as a disinfectant (1:1000).

19. The names of the following elements are associated with radioactive processes: astatine, radium, radon, actinium, protactinium.

Do you know that...

For production 1 t building bricks 1-2 m required 3 water, and for production 1 t nitrogen fertilizers and 1 ton of nylon - 600, 2500 m respectively 3 .

The layer of the atmosphere at an altitude of 10 to 50 km is called the ozonosphere. The total amount of ozone gas is small; at normal pressure and temperature O °C it would be distributed over earth's surface a thin layer of 2-3 mm. Ozone in the upper layers of the atmosphere absorbs most of the ultraviolet radiation sent by the Sun and protects all living things from its destructive influence.

Polycarbonate is a polymer that has interesting features. It can be hard like metal, elastic like silk, transparent like crystal, or colored in different colors. The polymer can be cast into a mold. It does not burn and retains its properties at temperatures from +135 to -150 °C.

Ozone is toxic. In low concentrations (during a thunderstorm), the smell of ozone is pleasant and refreshing. When the concentration in the air exceeds 1%, its odor is extremely unpleasant and impossible to breathe.

A crystal of table salt with slow crystallization can reach a size of more than half a meter.

Pure iron is found on Earth only in the form of meteorites.

Burning magnesium cannot be extinguished with carbon dioxide, since it interacts with it and continues to burn due to the oxygen released.

The most refractory metal is tungsten (t pl 3410 °C), and the most fusible metal is cesium (t pl 28.5 °C).

The largest gold nugget found in the Urals in 1837 weighed about 37 kg. A gold nugget weighing 108 kg was found in California, and 250 kg in Australia.

Beryllium is called the metal of indefatigability, because springs made from its alloy can withstand up to 20 billion load cycles (they are practically eternal).

INTERESTING FIGURES AND FACTS

Freon substitutes. As is known, freons and other synthetic substances containing chlorine and fluorine destroy ozone layer atmosphere. Soviet scientists have found a replacement for freon - hydrocarbon propylanes (compounds of propane and butane), harmless to the atmospheric layer. By 1995, the chemical industry will produce 1 billion aerosol packages.

TU-104 and plastics. The TU-104 aircraft contains 120,000 parts made of organic glass, other plastics and various combinations of them with other materials.

Nitrogen and lightning. About 100 lightning strikes every second are one of the sources of nitrogen compounds. In this case, the following processes occur:

N 2 + O 2 = 2NO

2NO+O 2 =2NO 2

2NO 2 +H 2 O+1/2O 2 =2HNO 3

This way, nitrate ions enter the soil and are absorbed by plants.

Methane and warming. The methane content in the lower atmosphere (troposphere) averaged 0.0152 ppm 10 years ago. and was relatively constant. Recently, there has been a systematic increase in its concentration. An increase in methane content in the troposphere contributes to an increase in the greenhouse effect, as methane molecules absorb infrared radiation.

Ash in sea water. There are dissolved gold salts in the water of the seas and oceans. Calculations show that the water of all seas and oceans contains about 8 billion tons of gold. Scientists are looking for the most profitable ways to extract gold from seawater. 1 ton of sea water contains 0.01-0.05 mg of gold.

"White Soot" . In addition to the usual, well-known black soot, there is also “white soot”. This is the name given to powder made from amorphous silicon dioxide, which is used as a filler for rubber in the manufacture of rubber.

Threat from trace elements. Active circulation of accumulated in natural environments microelements creates, according to experts, a serious threat to the health of modern people and future generations. Their sources are millions of tons of annually burned fuel, blast furnace production, non-ferrous metallurgy, introduced into the soil mineral fertilizers etc.

Transparent rubber.When making rubber from rubber, zinc oxide is used (it accelerates the vulcanization process of rubber). If zinc peroxide is added to rubber instead of zinc oxide, the rubber becomes transparent. Through a layer of such rubber 2 cm thick you can freely read a book.

Oil is more valuable than gold.Many types of perfumes require rose oil. It is a mixture of aromatic substances extracted from rose petals. To obtain 1 kg of this oil, it is necessary to collect and chemically treat 4-5 tons of petals. Rose oil is three times more expensive than gold.

Iron is inside us.The adult human body contains 3.5 g of iron. This is very little compared to, for example, calcium, of which there is more than 1 kg in the body. But if we compare not the total content of these elements, but their concentration only in the blood, then there is five times more iron than calcium. The bulk of the iron in the body is concentrated in red blood cells (2.45 g). Iron is found in muscle protein - myoglobin and in many enzymes. 1% of iron constantly circulates in plasma - the liquid part of the blood. The main “depot” of iron is the liver: here an adult man can store up to 1 g of iron. There is a constant exchange between all tissues and organs containing iron. The blood brings about 10% of iron to the bone marrow. It is part of the pigment that colors hair.

Phosphorus - element of life and thought. In animals, phosphorus is concentrated mainly in the skeleton, muscles and nervous tissue. The human body contains on average about 1.5 kg of phosphorus. Of this mass, 1.4 kg is bones, about 130 g is muscles and 12 g is nerves and brain. Almost all physiological processes, occurring in our body, are associated with the transformations of organophosphorus substances.

Asphalt Lake. On the island of Trinidad in the Lesser Antilles group there is a lake filled not with water, but with frozen asphalt. Its area is 45 hectares, and its depth reaches 90 m. It is believed that the lake was formed in the crater of a volcano, into which oil penetrated through underground cracks. Millions of tons of asphalt have already been extracted from it.

Microalloying.Microalloying is one of the central problems of modern materials science. By introducing small amounts (approximately 0.01%) of certain elements, it is possible to significantly change the properties of the alloys. This is due to segregation, i.e. the formation of an excessive concentration of alloying elements on structural defects.

Types of coal. "Colorless Coal"- this is gas, “yellow coal” is solar energy, “green coal” is vegetable fuel, “blue coal” is the energy of the ebb and flow of the seas, “blue coal” is driving force wind, “red coal” - the energy of volcanoes.

Native aluminum.Recent discoveries of native metallic aluminum have raised the question of how it is formed. According to scientists, in natural melts, under the influence of electrotelluric currents (electric currents flowing in the earth's crust), electrochemical reduction of aluminum occurs.

Plastic nail.Plastics - polycarbonates - turned out to be suitable for making nails. Nails made from them are driven freely into the board and do notrust, in many cases an excellent replacement for iron nails.

Sulfuric acid in nature. Sulfuric acid is obtained fromchemical plants. It turned out that it is formed in nature, primarily in volcanoes. For example, in the waters of the Rio Negro River, which originates from the Puracho volcano in South America, in the crater of which sulfur is formed, contains up to0.1% sulfuric acid. The river carries up to 20 liters of “volcanic” sulfuric acid into the sea every day. In the USSR, sulfuric acid was discovered by Academician Fersman in sulfur deposits in the Karakum Desert.

Exciting chemistry games

Who is faster and bigger?The teacher invites the game participants to write the names of elements ending in the same letter, for example, “n” (argon, krypton, xenon, lanthanum, molybdenum, neon, radon, etc.). The game can be complicated by asking you to find these elements in a table

D.I. Mendeleev and indicate which of them are metals and which non-metals.

Make up the names of the elements.The teacher calls the student to the board and asks him to write down a series of syllables. The rest of the students write them down in their notebooks. Task: in 3 minutes, create possible names of elements from the written syllables. For example, from the syllables “se, tiy, diy, ra, lion, li” you can make the words: “lithium, sulfur, radium, selenium.”

Drawing up reaction equations.“Who knows how to quickly create reaction equations, for example, between a metal and oxygen? - asks the teacher, addressing the participants in the game. - Write down the equation for the reaction of aluminum oxidation. Whoever writes the equation first, let him raise his hand.”

Who knows more?The teacher closes the table with a strip of paper

D.I. Mendeleev any group of elements (or period) and alternately invites the teams to name and write the signs of the elements closed group(or period). The winner is the student who names the most chemical elements and writes their symbols correctly.

The meaning of the names of elements translated from a foreign language.What does the word “bromine” mean in Greek? The same game can also be played with participants finding out the meaning of the names of elements translated from Latin (for example, ruthenium, tellurium, gallium, hafnium, lutetium, holmium, etc.).

Name the formula. The teacher names a compound, for example, magnesium hydroxide. The players, holding tablets with formulas, run out, holding a tablet with the corresponding formula in their hands.

Charades, puzzles,

teawords, crosswords.

1 . The first four letters of the surname of the famous Greek philosopher" indicate the word "people" in Greek without the last letter, the last four are an island in the Mediterranean Sea; in general - the surname of the Greek philosopher, founder of the atomic theory.(Demos, Crete - Democritus.)

2. The first syllable of the name of a chemical element is also the first of the name of one of the elements of the platinum group; in general, it is the metal for which Marie Skłodowska-Curie received the Nobel Prize.(Radon, rhodium - radium.)

3. The first syllable of the name of a chemical element is also the first of the name of the “lunar element”; the second is the first in the name of the metal discovered by M. Skłodowska-Curie; in general it is (in alchemical language) “the bile of the god Vulcan.”(Selenium, radium - sulfur.)

4. The first syllable of the name is also the first syllable of the name of an asphyxiating gas produced by the synthesis of carbon monoxide (II) and chlorine; the second syllable is the first of the name of a solution of formaldehyde in water; in general, it is a chemical element about which A.E. Fersman wrote that it is an element of life and thought.(Phosgene, formalin- phosphorus.)

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 this has always been the case, at least there is a lot of historical evidence of this.

The materials in the section “Chemistry at school and at home” will describe simple and interesting experiments. All of them turn out well if you strictly follow the given recommendations: after all, the course of the reaction is often influenced 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 of their addition to each other.

Any chemical experiments require caution, attention and accuracy when performed. Following three simple rules will help you avoid unpleasant surprises.

First: There is no need to experiment at home with unfamiliar substances. Don't forget that too much of a well-known chemical can also become dangerous in the wrong hands. Never exceed the amounts of substances specified in the experiment description.

Second: before performing any experience, you need to carefully read its description and understand the properties of the substances used. There are textbooks, reference books and other literature for this.

Third: one must be careful and prudent. If experiments involve 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 a chemistry class or in the open air. If during the experiment any substances are scattered or splashed, then it is necessary to protect yourself with protective glasses 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 chemistry club leader.

If these rules are followed, the experiments will be successful. Then chemical substances will reveal to you the wonders of their transformations.

Christmas tree in the snow

For this experiment, you need to get a glass bell, a small aquarium, or, as a last resort, 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, the plastic Christmas tree is sprayed with concentrated hydrochloric acid in a fume hood and immediately placed under a bell, jar or aquarium (Fig. 1). Keep the Christmas tree under the bell for 10–15 minutes, then quickly, slightly raising the bell, place a small cup with a concentrated ammonia solution next to the Christmas tree. Immediately, crystalline “snow” appears in the air under the bell, which settles on the Christmas tree, and soon it is all covered with crystals similar to 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 tiny colorless crystals of ammonium chloride, showering the Christmas tree.

Sparkling Crystals

How can one 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 while stirring a little hot distilled or boiled water until all the crystals have dissolved. Leave the solution in the dark so that upon cooling, crystallization of the double salt of the composition Na 2 SO 4 2K 2 SO 4 10H 2 O begins. As soon as crystals begin to separate, the solution will sparkle: weakly at 60 ° C, and stronger and stronger as it cools. When a lot of crystals fall out, you will see a whole sheaf of sparks.

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

The reason for the release of light is the redox reactions of converting 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 = C 6 H 4 O 2 + 2H 2 O,

HCHO + H 2 O 2 = HCOOH + H 2 O.

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

2HCOOH + K 2 CO 3 = 2HCOOC + 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 this 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 + 2KCl.

Filter the resulting colorless precipitate of Ba(BrO3)2 crystals and wash it 2–3 times with small (5–10 ml) portions of cold water. Then air dry the washed sediment. After this, dissolve 2 g of the resulting Ba(BrO 3) 2 in 50 ml of boiling water and filter the still hot solution.

Set 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, reheat the water using an electric stove.

Close the windows with curtains or turn off the lights in the room, and you will see how in the glass, simultaneously with the appearance of crystals, blue sparks - “lightning” - will appear in one place or another and clapping sounds of “thunder” will be heard. Here you have 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

Tap water is poured into a glass and a piece of “dry ice” - solid carbon dioxide CO 2 - is thrown into it. The water will immediately begin to bubble, and thick white “smoke” will pour out of the glass, formed by cooled water vapor, which is carried along by sublimating carbon dioxide. This “smoke” is completely safe.

Carbon dioxide. Solid carbon dioxide sublimes without melting at a low temperature of –78 °C. In the liquid state, CO 2 can only be under pressure. Carbon dioxide gas is a colorless, nonflammable gas with a mild sour taste. Water is capable of dissolving a significant amount of CO 2 gas: 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 hydrocarbonate 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 show how the substance disappears without a trace, disappearing without flame or smoke. To do this, pile up several tablets of “dry alcohol” (solid fuel based on hexamine), and pour a pinch of chromium(III) oxide Cr 2 O 3 preheated in a metal spoon on top. And what? There is no flame, no smoke, and the slide gradually decreases in size. After some time, all that remains is a pinch of unspent green powder - the catalyst Cr 2 O 3.

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

(CH 2) 6 N 4 + 9O 2 = 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

You can show another experiment with the mysterious disappearance of a substance, which at first glance seems to be simply witchcraft. Prepare copper wire 0.8–1.0 mm thick: clean it with sandpaper and roll it into a ring with a diameter of 3–4 cm. Bend a piece of wire 10–15 cm long, which will serve as a handle, and to keep it cool, The end of this segment is put on a piece of pencil from which the lead has been previously removed.

Then pour 10–15 ml of acetone (CH 3) 2 CO into a glass (don’t forget: acetone is flammable!).

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

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Rice. 2. Disappearance of acetone

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

2(CH 3) 2 CO + O 2 = CH 3 COOH + 2CH 3 CHO,

with the release of a large amount of heat, so the wire becomes red-hot. The vapors of both reaction products are colorless; they are identified only by the smell.

"Dry acid"

If you put a piece of “dry ice” - solid carbon dioxide - into a flask and close it with a stopper with gas outlet pipe, and put the end of this tube into a test tube with water, where blue litmus was added in advance, then a small miracle will soon happen.

Warm 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 peel a chicken egg without breaking the shell? If you dip it in dilute hydrochloric or nitric acid, the shell will completely dissolve and the white and yolk will remain, surrounded by a thin film.

This experience can be demonstrated in a very impressive way. You need to take a flask or glass bottle with a wide neck, pour diluted hydrochloric or nitric acid into it 3/4 of the volume, place a raw egg on the neck of the flask, and then carefully heat 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 inside the vessel with the acid (although the egg is larger in cross-section than the neck of the flask).

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

Who didn't believe in miracles as a child? To have a fun and educational time with your baby, you can try experiments in entertaining chemistry. They are safe, interesting and educational. These experiments will answer many children's “whys” and awaken interest in science and knowledge of the world around us. And today I want to tell you what experiments parents can organize for children at home.

Pharaoh's snake

This experience is based on increasing the volume of mixed reagents. During the burning process, they transform and, wriggling, resemble a snake. The experiment got its name from a biblical miracle when Moses, who came to Pharaoh with a request, turned his rod into a snake.

For the experiment you will need the following ingredients:

• ordinary sand;
• ethanol;
• crushed sugar;
• baking soda.

We soak the sand in alcohol, then form a small hill out of it and make a depression at the top. After this, mix a small spoon of powdered sugar and a pinch of soda, then pour everything into an improvised “crater”. We set fire to our volcano, the alcohol in the sand begins to burn out, and black balls form. They are a product of the decomposition of soda and caramelized sugar.

After all the alcohol has burned out, the pile of sand will turn black and a wriggling “black pharaoh’s snake” will form. This experiment looks more impressive with the use of real reagents and strong acids, which can only be used in a chemical laboratory.

You can do it a little easier and buy a calcium gluconate tablet at the pharmacy. Set it on fire at home, the effect will be almost the same, only the “snake” will quickly collapse.

Magic lamp

In stores you can often see lamps, inside of which a beautiful illuminated liquid moves and shimmers. Such lamps were invented in the early 60s. They work on the basis of paraffin and oil. At the bottom of the device there is a built-in conventional incandescent lamp, which heats the descending molten wax. Part of it reaches the top and falls, the other part heats up and rises, so we see a kind of “dance” of paraffin inside the container.

In order to carry out a similar experience at home with a child, we will need:

• any juice;
• vegetable oil;
• effervescent tablets;
• beautiful container.

Take a container and fill it more than halfway with juice. Add vegetable oil on top and throw in an effervescent tablet. It begins to “work”, the bubbles rising from the bottom of the glass capture the juice and form a beautiful bubbling in the oil layer. Then the bubbles reaching the edge of the glass burst and the juice falls down. It turns out to be a kind of “circulation” of juice in a glass. Such magic lamps are absolutely harmless, unlike paraffin lamps, which a child can accidentally break and get burned.

Ball and orange: experience for kids

What will happen to a balloon if you drop orange or lemon juice on it? It will burst as soon as the citrus droplets touch it. And you can then eat the orange with your baby. It's very entertaining and fun. For the experiment we will need a couple of balloons and citrus. We inflate them and let the baby drip some fruit juice onto each one and see what happens.

Why does the balloon burst? It's all about a special chemical - limonene. It is found in citrus fruits and is often used in the cosmetics industry. When the juice comes into contact with the rubber of the balloon, a reaction occurs, limonene dissolves the rubber and the balloon bursts.

Sweet glass

You can make amazing things from caramelized sugar. In the early days of cinema, edible sweet glass was used in most fight scenes. This is because it is less traumatic for actors during filming and is inexpensive. Its fragments can then be collected, melted and made into film props.

Many people made sugar cockerels or fudge in childhood; glass should be made according to the same principle. Pour water into the pan, heat it up a little, the water should not be cold. After this, add granulated sugar and bring to a boil. When the liquid boils, cook until the mixture gradually begins to thicken and bubbles strongly. The melted sugar in the container should turn into viscous caramel, which, if lowered into cold water, will turn into glass.

Pour the prepared liquid onto the previously prepared and lubricated vegetable oil pan, cool and the sweet glass is ready.

During the cooking process, you can add dye to it and cast it into some interesting shape, and then treat and surprise everyone around you.

Philosophical nail

This entertaining experiment is based on the principle of copper plating of iron. Named by analogy with a substance that, according to legend, could turn everything into gold, and was called the philosopher's stone. To conduct the experiment we will need:

• iron nail;
• a quarter of a glass of acetic acid;
• table salt;
• soda;
• a piece of copper wire;
• glass container.

Take a glass jar and pour acid and salt into it and stir well. Be careful, vinegar has a strong, unpleasant odor. It can burn the baby's delicate airways. Then we put copper wire into the resulting solution for 10-15 minutes, after some time we lower an iron nail, previously cleaned with soda, into the solution. After some time, we can see that a copper coating has appeared on it, and the wire has become shiny as new. How could this happen?

Copper reacts with acetic acid to form a copper salt, then the copper ions on the surface of the nail exchange places with iron ions and form a coating on the surface of the nail. And the concentration of iron salts in the solution increases.

Copper coins are not suitable for the experiment because this metal itself is very soft, and to make the money stronger, its alloys with brass and aluminum are used.

Copper products do not rust over time; they are covered with a special green coating - patina, which prevents it from further corrosion.

DIY soap bubbles

Who didn't love blowing soap bubbles as a child? How beautifully they shimmer and burst merrily. You can simply buy them in the store, but it will be much more interesting to create your own solution with your child and then blow bubbles.

It should be said right away that the usual mixture of laundry soap and water won't do. It produces bubbles that quickly disappear and are difficult to blow out. Most affordable way To prepare such a substance, mix two glasses of water with a glass of dishwashing detergent. If you add sugar to the solution, the bubbles become stronger. They will fly for a long time and will not burst. And the huge bubbles that can be seen on stage by professional artists are created by mixing glycerin, water and detergent.

For beauty and mood, you can mix food coloring into the solution. Then the bubbles will glow beautifully in the sun. You can create several different solutions and use them in turn with your child. It's interesting to experiment with color and create your own new shade of soap bubbles.

You can also try mixing soap solution with other substances and see how they affect the bubbles. Maybe you will invent and patent some new type of yours.

Spy ink

This legendary invisible ink. What are they made of? Now there are so many films about spies and interesting intellectual investigations. You can invite your child to play secret agents a little.

The point of such ink is that it cannot be seen on paper with the naked eye. Only by applying a special influence, for example, heating or chemical reagents you can see the secret message. Unfortunately, most recipes for making them are ineffective and such ink leaves marks.

We will make special ones that are difficult to see without special identification. For this you will need:

• water;
• spoon;
• baking soda;
• any heat source;
• stick with cotton on the end.

Pour warm liquid into any container, then, stirring, pour baking soda into it until it stops dissolving, i.e. the mixture will reach a high concentration. We put a stick with cotton wool at the end there and write something on paper with it. Let's wait until it dries, then bring the sheet to a lit candle or gas stove. After a while, you can see how the yellow letters of the written word appear on the paper. Make sure that the leaf does not catch fire while developing the letters.

Fireproof money

This is a famous and old experiment. For it you will need:

• water;
• alcohol;
• salt.

Take a deep glass container and pour water into it, then add alcohol and salt, stir well until all ingredients dissolve. To set it on fire, you can take ordinary pieces of paper, or if you don’t mind, you can take a banknote. Just take a small denomination, otherwise something may go wrong in the experiment and the money will be spoiled.

Place strips of paper or money in a water-salt solution; after a while they can be removed from the liquid and set on fire. You can see that the flame covers the entire bill, but it does not light up. This effect is explained by the fact that the alcohol in the solution evaporates, and the wet paper does not light up.

Wish-fulfilling stone

The process of growing crystals is very exciting, but labor-intensive. However, what you get as a result will be worth your time. The most popular is the creation of crystals from table salt or sugar.

Let's consider growing a “wishing stone” from refined sugar. For this you will need:

• drinking water;
• granulated sugar;
• piece of paper;
• thin wooden stick;
• small container and glass.

First, let's make the preparation. To do this we need to prepare a sugar mixture. Pour some water and sugar into a small container. Let the mixture boil and cook until it becomes syrupy. Then we lower the wooden stick there and sprinkle it with sugar, this must be done evenly, in this case the resulting crystal will become more beautiful and even. Leave the base for the crystal overnight to dry and harden.

Let's start preparing the syrup solution. Pour water into a large container and add sugar, stirring slowly. Then, when the mixture boils, cook it until it becomes a viscous syrup. Remove from heat and let cool.

We cut out circles from paper and attach them to the end of a wooden stick. It will become the lid on which the wand with crystals is attached. Fill the glass with the solution and lower the workpiece into it. We wait for a week, and the “wishing stone” is ready. If you add dye to the syrup during cooking, it will turn out even more beautiful.

The process of creating crystals from salt is somewhat simpler. Here you just need to monitor the mixture and change it periodically in order to increase the concentration.

First of all, we create a blank. Pour into a glass container warm water, and gradually stirring, add salt until it stops dissolving. Leave the container for a day. After this time, you can find many small crystals in the glass; choose the largest one and tie it to a thread. Make a new salt solution and put a crystal there; it must not touch the bottom or edges of the glass. This may lead to unwanted deformations.

After a couple of days you can notice that he has grown. The more often you change the mixture, increasing the concentration of salt, the faster you can grow your wishing stone.

Glowing tomato

This experiment must be carried out strictly under the supervision of adults, as it uses harmful substances. The glowing tomato that will be created during this experiment should absolutely not be eaten, as it can lead to death or severe poisoning. We will need:

• regular tomato;
• syringe;
• sulfuric matter from matches;
• bleach;
• hydrogen peroxide.

We take a small container, put pre-prepared match sulfur there and pour in bleach. We leave all this for a while, after which we draw the mixture into a syringe and inject it inside the tomato with different sides, so that it glows evenly. To start the chemical process, hydrogen peroxide is needed, which we introduce through the trace from the petiole from above. We turn off the lights in the room and we can enjoy the process.

Egg in vinegar: a very simple experiment

This is a simple and interesting ordinary acetic acid. To implement it you will need a boiled chicken egg and vinegar. Take a transparent glass container and place an egg in its shell in it, then fill it to the top with acetic acid. You can see bubbles rising from its surface; this is a chemical reaction taking place. After three days, we can observe that the shell has become soft and the egg is elastic, like a ball. If you shine a flashlight on it, you can see that it glows. Conduct an experiment with raw egg not recommended, as the soft shell may rupture when squeezed.

DIY slime made from PVA

This is a fairly common strange toy from our childhood. Currently it is quite difficult to find it. Let's try to make slime at home. Its classic color is green, but you can use the one you like. Try mixing several shades and creating your own unique color.

To conduct the experiment we will need:

• glass jar;
• several small glasses;
• dye;
• PVA glue;
• regular starch.

Let's prepare three identical glasses with solutions that we will mix. Pour PVA glue into the first, water into the second, and dilute starch into the third. First, pour water into the jar, then add glue and dye, stir everything thoroughly and then add starch. The mixture needs to be stirred quickly so that it does not thicken, and you can play with the finished slime.

How to quickly inflate a balloon

Is there a holiday coming up and you need to inflate a lot of balloons? What to do? This unusual experience will help make the task easier. For it we need a rubber ball, acetic acid and regular soda. It must be carried out carefully in the presence of adults.

Pour a pinch of soda into a balloon and place it on the neck of a bottle of acetic acid so that the soda does not spill out, straighten the balloon and let its contents fall into the vinegar. You will see a chemical reaction take place and it will begin to foam, releasing carbon dioxide and inflating the balloon.

That's all for today. Don’t forget, it’s better to conduct experiments for children at home under supervision, it will be safer and more interesting. See you again!

Household chemist-scientists believe that the most useful property detergents - this is the content of surfactants (surfactants). Surfactants significantly reduce the electrostatic voltage between particles of substances and break down conglomerates. This property makes clothes easier to clean. In this article chemical reactions, which you can repeat with household chemicals, because with the help of surfactants you can not only remove dirt, but also conduct spectacular experiments.

Experience one: foam volcano in a jar

Carry out this interesting experiment at home it is very simple. For it you will need:

hydroperite, or (the higher the concentration of the solution, the more intense the reaction will be and the more spectacular the eruption of the “volcano”; therefore, it is better to buy tablets at the pharmacy and immediately before use, dilute them in a small volume in a ratio of 1/1 (you will get a 50% solution - this is an excellent concentration);

gel dishwashing detergent (prepare approximately 50 ml of aqueous solution);

dye.

Now we need to obtain an effective catalyst - ammonia. Carefully add ammonia liquid drop by drop until completely dissolved.

Copper sulfate crystals

Consider the formula:

CuSO₄ + 6NH₃ + 2H₂O = (OH)₂ (copper ammonia) + (NH₄)₂SO₄

Peroxide decomposition reaction:

2H₂O₂ → 2H₂O + O₂

We make a volcano: mix ammonia with a washing solution in a jar or wide-necked flask. Then quickly pour in the hydroperite solution. The “eruption” can be very strong - to be on the safe side, it is better to place some kind of container under the volcano flask.

Experiment two: reaction of acid and sodium salts

Perhaps this is the most common compound that is found in every home - baking soda. It reacts with the acid, and the result is new salt, water and carbon dioxide. The latter can be detected by hissing and bubbles at the site of the reaction.

Experiment three: “floating” soap bubbles

It's a very simple experience with baking soda. You will need:

• aquarium with a wide bottom;
• baking soda (150-200 grams);
• (6-9% solution);
• soap bubbles (to make your own, mix water, dish soap and glycerin);

Spread baking soda evenly along the bottom of the aquarium and fill it with acetic acid. The result is carbon dioxide. It is heavier than air and therefore settles at the bottom of the glass box. To determine whether there is CO₂ there, lower a lit match to the bottom - it will instantly go out in carbon dioxide.

NaHCO₃ + CH₃COOH → CH₃COONa + H₂O + CO₂

Now you need to blow bubbles into the container. They will slowly move along a horizontal line (the boundary between carbon dioxide and air, invisible to the eye, as if floating in an aquarium).

Experiment four: reaction of soda and acid 2.0

For the experience you will need:

• different types of non-hygroscopic food products(for example, chewing marmalade).
• a glass of diluted baking soda (one tablespoon);
• a glass with a solution of acetic or any other available acid (malic,).

Cut pieces of marmalade with a sharp knife into strips 1-3 cm long and place for processing in a glass with soda solution. Wait 10 minutes and then transfer the pieces to another glass (with an acid solution).

The ribbons will become overgrown with bubbles of carbon dioxide formed and float to the top. The bubbles on the surface will evaporate, the lifting force of the gas will disappear, and the marmalade ribbons will sink and again become overgrown with bubbles, and so on until the reagents in the container run out.

Experience five: properties of alkali and litmus paper

Most detergents contain caustic soda, the most common alkali. Its presence in a detergent solution can be detected in this elementary experiment. At home, a young enthusiast can easily carry it out on his own:

• take a strip of litmus paper;
• dissolve a little liquid soap in water;
• dip litmus in soapy liquid;
• wait for the indicator to color Blue colour, which will indicate an alkaline reaction of the solution.

Click to find out what other experiments to determine the acidity of the medium can be carried out using available substances.

Experience six: colored explosions in milk

The experience is based on the properties of interaction between fats and surfactants. Fat molecules have a special, dual structure: hydrophilic (interacting, dissociating with water) and hydrophobic (water-insoluble “tail” of a polyatomic compound) end of the molecule.

1. Pour milk into a wide container of shallow depth (“canvas” on which a color explosion will be visible). Milk is a suspension, a suspension of fat molecules in water.
2. Using a pipette, add a few drops of water-soluble liquid dye to the milk container. You can add different dyes to different places in the container and create a multi-color explosion.
3. Then you need to moisten a cotton swab in liquid detergent and touch the surface of the milk. The white “canvas” of milk turns into a moving palette with colors that move in the liquid like spirals and twist into bizarre curves.

This phenomenon is based on the ability of a surfactant to fragment (divide into sections) a film of fat molecules on the surface of a liquid. Fat molecules, repelled by their hydrophobic “tails,” migrate in the milk suspension, and with them the partially undissolved paint.