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Municipal budgetary educational institution
"Secondary school No. 35", Bryansk
Entertaining experiences in chemistry
Developed
chemistry teacher of the highest category
Velicheva Tamara Alexandrovna
When conducting experiments, it is necessary to observe safety precautions, skillfully handle substances, utensils and appliances. These experiments do not require complex equipment and expensive reagents, and the effect of their impact on the audience is huge.
"Golden" nail.
Pour 10-15 ml of copper sulfate solution into a test tube and add a few drops of sulfuric acid. An iron nail is dipped into the solution for 5-10 seconds. A red coating of metallic copper appears on the surface of the nail. To give shine, the nail is rubbed with filter paper.
Pharaoh snakes.
Crushed dry fuel is placed on the asbestos mesh. Norsulfazole tablets are placed around the top of the hill at the same distance from each other. During the demonstration of the experiment, the top of the hill is set on fire with a match. During the experiment, it is monitored that three independent “snakes” are formed from three norsulfazole tablets. To prevent sticking of the reaction products into one "snake", it is necessary to correct the resulting "snakes" with a splinter.
Bank explosion.
Take for experience tin can from coffee (without a lid) with a capacity of 600-800 ml and punch a small hole in the bottom. The jar is placed upside down on the table and, having closed the hole with a damp piece of paper, a gas outlet tube from the Kiryushkin device for filling with hydrogen is brought from below ( the jar is filled with hydrogen for 30 seconds). Then the tube is removed, and the gas is ignited with a long splinter through the hole in the bottom of the jar. At first, the gas burns quietly, and then the buzz begins and an explosion occurs. The jar bounces high up and flames burst out. The explosion occurs because an explosive mixture has formed in the bank.
"Dance of the Butterflies".
For experience, “butterflies” are made in advance. The wings are cut out of tissue paper and glued to the body (fragments of a match or toothpick) for greater stability in flight.
A wide-mouthed jar is prepared, hermetically sealed with a stopper, into which a funnel is inserted. The diameter of the funnel at the top should be no more than 10 cm. Pour into a jar acetic acid CH 3 COOH so that the lower end of the funnel does not reach the surface of the acid by about 1 cm. Then, through a funnel, several tablets of sodium bicarbonate (NaHCO 3) are thrown into a jar of acid, and the "butterflies" are placed in a funnel. They begin to "dance" in the air.
"Butterflies" are kept in the air by a jet of carbon dioxide formed as a result of a chemical reaction between sodium bicarbonate and acetic acid:
NaHCO 3 + CH 3 COOH \u003d CH 3 COONa + CO 2 + H 2 O
Lead coat.
A human figure is cut out of a thin zinc plate, cleaned well and lowered into a glass with a solution of tin chloride SnCl 2 . A reaction begins, as a result of which the more active zinc displaces the less active tin from the solution:
Zn + SnCl 2 = ZnCl 2 + Sn
The zinc figurine begins to be covered with shiny needles.
Fire cloud.
Flour is sifted through a frequent sieve and flour dust is collected, which settles far along the sides of the sieve. It dries well. Then two full teaspoons of flour dust are introduced into a glass tube, closer to the middle, and shake it a little along the length of the tube by 20-25 cm.
Then the dust is strongly blown over the flame of an alcohol lamp placed on a demonstration table (the distance between the end of the tube and the alcohol lamp should be about one meter).
A "fiery" cloud is formed.
"Star Rain.
Take three teaspoons of iron powder, the same amount of pounded charcoal. All this is mixed and poured into a crucible. It is fixed in a tripod and heated on a spirit lamp. Soon the "starry" rain begins.
These incandescent particles are ejected from the crucible by carbon dioxide formed during the combustion of coal.
Changing the color of flowers.
In a large battery glass, a mixture is prepared from three parts of diethyl ether C 2 H 5 ─ O ─ C 2 H 5 and one part (by volume) of a strong solution of ammonia NH 3 ( there should be no fire nearby). Ether is added in order to facilitate the penetration of ammonia into the cells of the flower petal.
Individual flowers or a bunch of flowers are dipped into an ether-ammonia solution. This will change their color. Red, blue and purple flowers turn green, white White Rose, chamomile) - will turn into dark, yellow will retain their natural color. The changed color is preserved by flowers for several hours, after which it turns into natural.
This is due to the fact that the color of fresh flower petals is caused by natural organic dyes, which have indicator properties and change their color in an alkaline (ammonia) environment.
List of used literature:
Shulgin G.B. This fascinating chemistry. M. Chemistry, 1984.
Shkurko M.I. Entertaining experiments in chemistry. Minsk. Narodnaya Asveta, 1968.
Aleksinsky V.N. Entertaining experiments in chemistry. A guide for the teacher. M. Education, 1980.
Not a single person, even the slightest bit familiar with the problems modern education won't argue about the benefits Soviet system. However, it also had certain drawbacks, in particular, in the study of natural science subjects, the emphasis was often placed on providing a theoretical component, and practice was relegated to the background. At the same time, any teacher will confirm that The best way to arouse in a child an interest in these objects is to show some spectacular physical or chemical experience. This is especially important for initial stage study of such subjects and even long before that. In the second case good help for parents, a special kit for chemical experiments can be used, which can also be used at home. True, when purchasing such a gift, fathers and mothers should understand that they will also have to take part in classes, since such a “toy” in the hands of a child left unattended represents a certain danger.
What is a chemical experiment
First of all, you should understand what is at stake. In general, it is generally accepted that a chemical experiment is manipulations with various organic and inorganic substances in order to establish their properties and reactions in various conditions. If we are talking about experiments that are carried out in order to arouse in the child the desire to study the world they should be spectacular and at the same time simple. In addition, it is not recommended to choose options that require special security measures.
Where to begin
First of all, you can tell the child that everything that surrounds us, including his own body, consists of various substances that interact. As a result, various phenomena can be observed: both those to which people have long been accustomed and do not pay attention to them, and very unusual ones. In this case, rust, which is a consequence of the oxidation of metals, or smoke from a fire, which is a gas released during combustion, can be cited as an example. various items. Then you can start showing simple chemical experiments.
"Float Egg"
A very interesting experience can be shown using an egg and water solution of hydrochloric acid. To carry it out, you need to take a glass decanter or a wide glass and pour a 5% solution of hydrochloric acid onto the bottom. Then you need to lower the egg into it and wait a while.
Soon, on the surface of the egg shell, due to the reaction of hydrochloric acid and calcium carbonate contained in the shell, carbon dioxide bubbles will appear and lift the egg up. Having reached the surface, the gas bubbles will burst, and the "load" will again go to the bottom of the dish. The process of lifting and diving the egg will continue until all the eggshell has been dissolved in the hydrochloric acid.
"Secret Signs"
Interesting chemical experiments can be done with sulfuric acid. For example, with a cotton swab dipped in a 20% sulfuric acid solution, figures or letters are drawn on paper and wait for the liquid to dry. Then the sheet is ironed with a hot iron and black letters begin to appear. This experience will be even more spectacular if you hold the leaf over the flame of a candle, but this must be done very carefully, trying not to set fire to the paper.
"Fire Lettering"
The previous experience can be done differently. To do this, draw a contour of a figure or letter on a sheet of paper with a pencil and prepare a composition consisting of 20 g of KNO 3 dissolved in 15 ml of hot water. Then, with a brush, saturate the paper along the pencil lines so that there are no gaps. As soon as the audience is ready, and the sheet is dry, you need to bring a burning splinter to the inscription at only one point. Immediately a spark will appear, which will “run” along the outline of the drawing until it reaches the end of the line.
Surely young viewers will be interested in why such an effect is achieved. Explain that when heated, potassium nitrate turns into another substance - potassium nitrite and releases oxygen, which supports combustion.
"Fireproof Handkerchief"
Children will certainly be interested in the experience with "fireproof" fabric. To demonstrate it, 10 g of silicate glue is dissolved in 100 ml of water and a piece of cloth or handkerchief is moistened with the resulting liquid. Then it is squeezed out and, using tweezers, immersed in a container with acetone or gasoline. Immediately set fire to the fabric with a splinter and watch how the flame "devours" the handkerchief, but it remains intact.
"Blue Bouquet"
Simple chemical experiments can be very spectacular. We invite you to surprise the viewer by using paper flowers, the petals of which should be smeared with natural starch glue. Then the bouquet should be placed in a jar, a few drops of iodine alcohol tincture should be put on the bottom and the lid should be tightly closed. In a few minutes, a "miracle" will happen: the flowers will turn blue, because the iodine vapor will cause the starch to change its color.
"Christmas decorations"
An original chemistry experience that will give you beautiful jewelry for a mini-Christmas tree, it will turn out if you use a saturated solution (1:12) of potassium alum KAl (SO 4) 2 with the addition of copper sulfate CuSO 4 (1: 5).
First you need to make a frame of a figurine from a wire, wrap it with white woolen threads and lower them into a pre-prepared mixture. After a week or two, crystals will grow on the workpiece, which should be varnished so that they do not crumble.
"Volcanoes"
A very effective chemical experiment will turn out if you take a plate, plasticine, baking soda, table vinegar, red dye and dishwashing liquid. Next, you need to do the following:
- divide a piece of plasticine into two parts;
- roll one into a flat pancake, and fashion a hollow cone from the second, at the top of which you need to leave a hole;
- put the cone on a plasticine base and connect it so that the "volcano" does not let water through;
- put the structure on a tray;
- pour "lava", consisting of 1 tbsp. l. baking soda and a few drops of liquid food coloring;
- when the audience is ready, pour vinegar into the "vent" and watch the violent reaction, during which carbon dioxide is released, and red foam flows out of the volcano.
As you can see, home chemical experiments can be very diverse, and all of them will interest not only children, but also adults.
This manual increases interest in the subject, develops cognitive, mental, research activities. Students analyze, compare, study and generalize the material, receive new information and practical skills. Students can conduct some experiments on their own at home, but most in the classroom of a chemical circle under the guidance of a teacher.
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Preview:
town Novomikhailovsky
municipality
Tuapse district
"Chemical reactions around us"
Teacher:
Kozlenko
Alevtina Viktorovna
2015
« Volcano" on the table.Ammonium dichromate mixed with metallic magnesium is poured into the crucible (the mound in the center is moistened with alcohol). Light the "volcano" with a burning torch. The reaction is exothermic, proceeds rapidly, together with nitrogen, hot particles of chromium oxide (III) fly out and
burning magnesium. If you turn off the light, you get the impression of an erupting volcano, from the crater of which red-hot masses pour out:
(NH 4) 2 Cr 2 O 7 \u003d Cr 2 O 3 + 4H 2 O + N 2; 2Mg + O 2 \u003d 2MgO.
"Star Rain".Spread out on a sheet blank paper, mixing thoroughly, three tablespoons of potassium permanganate, coal powder and reduced iron powder. The resulting mixture is poured into an iron crucible, which is fixed in the tripod ring and heated with the flame of an alcohol lamp. The reaction starts and the mixture is ejected
in the form of many sparks, giving the impression of "fiery rain".
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 wall of the cylinder, then a few crystals of potassium permanganate are thrown. Sparks appear on the border between two liquids, accompanied by crackling. Alcohol ignites when oxygen appears, which is formed when potassium permanganate reacts with sulfuric acid.
"Green Fire" . Boric acid with ethyl alcohol form an ester:
H 3 BO 3 + 3C 2 H 5 OH \u003d B (OS 2 H 5) + 3H 2 O
Pour 1 g of boric acid into a porcelain cup, add 10 ml of alcohol and 1 ml of sulfuric acid. The mixture is stirred with a glass rod and ignited. Ether vapor burns with a green flame.
Water ignites paper. In a porcelain cup, sodium peroxide is mixed 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 \u003d H 2 O 2 + 2NaOH
2H 2 O 2 \u003d 2H 2 O + O 2 |
Multicolored flame.Various flame colors can be shown when chlorides are burned in alcohol. To do this, take clean porcelain cups with 2-3 ml of alcohol. 0.2-0.5 g of finely ground chlorides are added to the alcohol. The mixture is ignited. 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 chemical beakers are filled with solutions of litmus, methyl orange and phenolphthalein to about 3/4 of the volume.
In other glasses, solutions of hydrochloric acid and sodium hydroxide are prepared. Sodium hydroxide solution is collected with a glass tube. Stir the liquid in all the glasses with this tube, imperceptibly pouring out a small amount of the solution each time. The color of the liquid in the glasses will change. Then acid is collected in this way into the second tubeand mix liquids in glasses with it. The color of the indicators will again change dramatically.
Magic wand.For the experiment, a pre-prepared slurry of potassium permanganate and concentrated sulfuric acid is placed in porcelain cups. The glass rod is immersed in the freshly prepared oxidizing mixture. Quickly bring the stick to the damp wick of a spirit lamp or cotton wool soaked in alcohol, the wick ignites. (It is forbidden to bring a stick re-moistened with alcohol into the gruel.)
2KMnO 4 + H 2 SO 4 \u003d Mn 2 O 7 + K 2 SO 4 + H 2 O
6Mp 2 O 7 + 5C 2 H 5 OH + 12H 2 SO 4 \u003d l2MnSO 4 + 10CO 2 + 27H 2 O
Reaction proceeds with release a large number heat, alcohol is flammable.
Self-igniting liquid.0.5 g of potassium permanganate crystals slightly ground in a mortar are placed in a porcelain cup, and then 3-4 drops of glycerin are applied from a pipette. After a while, the glycerin ignites:
14KMnO 4 + 3C 3 H 6 (OH) 3 \u003d 14MnO 2 + 9CO 2 + 5H 2 O + 14KOH
Combustion of various substancesin molten crystals.
Three tubes are 1/3 filled with white crystals of potassium nitrate. All three test tubes are fixed vertically in a rack and simultaneously heated with three spirit 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" at the same time. In the second test tube, a piece of sulfur burns with a bright flame. In the third test tube, red phosphorus burns out, releasing such an amount of heat that the test tube melts.
Water is a catalyst.Mix gently on a glass plate
4 g of powdered iodine and 2 g of zinc dust. The reaction does not occur. A few drops of water are added to the mixture. An exothermic reaction begins with the release of a violet vapor of iodine, which reacts with zinc. The experiment is carried out under tension.
Self-ignition of paraffin.Fill 1/3 of the tubes with pieces of paraffin and heat to its boiling point. Boiling paraffin is poured from a test tube, from a height of about 20 cm, in a thin stream. Paraffin flares up and burns with a bright flame. (In a test tube, paraffin cannot ignite, since there is no air circulation. When paraffin is poured out 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 General Educational Institution
Secondary school No. 35
town Novomikhailovsky
municipality
Tuapse district
Entertaining experiences on the subject
"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 closed with lids and placed at some distance from each other. Before the experiment show that the cylinders let. During the demonstration, the hydrochloric acid cylinder (on the walls) is turned upside down and placed on the cap of the ammonia cylinder. The lid is removed: white smoke is formed.
Golden Knife. To 200 ml of a saturated solution of copper sulphate, add 1 ml of sulfuric acid. Take a knife, brushed sandpaper. Dip the knife for a few seconds in a solution of copper sulfate, take it out, 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 glass.Ammonium nitrate is poured into a glass of water and placed on wet plywood, which freezes to the glass.
Color solutions. Crystal hydrates of copper, nickel, and cobalt salts are dehydrated before the experiment. After adding water to them, colored solutions are formed. Anhydrous white copper salt powder form blue color solution, green nickel green salt powder, blue salt powder 4 cobalt red.
Blood without a wound. For the experiment, use 100 ml of a 3% solution of ferric chloride FeCI 3 in 100 ml of a 3% solution of potassium thiocyanate KCNS. To demonstrate the experience, a children's polyethylene sword is used. Call someone from the audience to the stage. Wash the palm with a cotton swab with a solution of FeCI 3 , and the sword is moistened with a colorless solution of KCNS. Next, the sword is drawn across the palm: “blood” flows abundantly on the paper:
FeCl 3 + 3KCNS \u003d Fe (CNS) 3 + 3KCl
"Blood" from the palm is washed off 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 "photo".Yellow and red blood salts, interacting with salts heavy metals, give reaction products of various colors: 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. The above salt solutions on white paper make a drawing and dry it. Since the solutions are colorless, the paper remains uncolored. For the development of such drawings, a wet swab moistened with a solution of yellow blood salt is carried out on paper.
The transformation of liquid into jelly.Pour 100 g of sodium silicate solution into a beaker and add 5 ml of 24% hydrochloric acid solution. Stir the mixture of these solutions with a glass rod and hold the rod in the solution vertically. After 1-2 minutes, the rod no longer falls in the solution, because the liquid has thickened so that it does not pour out of the glass.
Chemical vacuum in a flask. Fill the flask with carbon dioxide. A little concentrated solution of potassium hydroxide is poured into it and the opening of the bottle is closed with a peeled hard-boiled egg, the surface of which is smeared with a thin layer of petroleum jelly. The egg gradually begins to be drawn into the bottle and, with a sharp sound of a shot, falls on her bottom.
(A vacuum was formed in the flask as a result of the reaction:
CO 2 + 2KOH \u003d K 2 CO 3 + H 2 O.
Outside air pressure pushes the egg.)
Fireproof handkerchief.The handkerchief is impregnated with a solution of sodium silicate, dried and folded. To demonstrate incombustibility, it is moistened with alcohol and set on fire. The handkerchief should be kept straightened with crucible tongs. The alcohol burns off, and the fabric impregnated with sodium silicate remains unharmed.
Sugar is on 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 quickly burns out.
(The ashes contain lithium compounds that act as a catalyst.)
Charcoal from sugar. Weigh out 30 g of powdered sugar and transfer it to a beaker. Pour ~ 12 ml of concentrated sulfuric acid into powdered sugar. Mix sugar and acid with a glass rod into a mushy mass. After a while, the mixture turns black and heats up, and soon a porous coal mass begins to crawl out of the glass.
Municipal Autonomous General Educational Institution
Secondary school No. 35
town Novomikhailovsky
municipality
Tuapse district
Entertaining experiences on the subject
"Chemistry in Nature"
Teacher:
Kozlenko
Alevtina Viktorovna
2015
Extraction of "gold".In one flask with hot water dissolve lead acetate, and in the other - potassium iodide. Both solutions are poured into a large flask, the mixture is allowed to cool and show beautiful golden scales floating in the solution.
Pb (CH 3 COO) 2 + 2KI \u003d PbI 2 + 2CH3COOK
Mineral "chameleon".3 ml of a saturated potassium permanganate solution and 1 ml of a 10% potassium hydroxide solution are poured into a test tube.
10-15 drops of sodium sulfite solution are added to the resulting mixture while shaking until a dark green color appears. When stirred, the color of the solution turns blue, then purple and finally raspberry.
The appearance of a dark green color is due to the formation of potassium manganate
K 2 MPO 4:
2KMpo 4 + 2KOH + Na 2 SO 3 \u003d 2K 2 MnO 4 + Na 2 SO 4 + H 2 O.
The change in the dark green color of the solution is due to the decomposition of potassium manganate under the influence of atmospheric oxygen:
4K 2 MnO 4 + O 2 + 2H 2 O \u003d 4KMpO 4 + 4KON.
The transformation of red phosphorus into white.A glass rod is lowered into a dry test tube and red phosphorus is placed in the amount of half a pea. The bottom of the test tube is very hot. First, there is white smoke. 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 stopping the heating of the test tube, the glass rod is removed. White phosphorus ignites on it. With the end of a glass rod, white phosphorus is also removed from the inner walls of the test tube. In the air there is a second flash.
The experiment is carried out only by the teacher.
Pharaoh snakes. For the experiment, a salt is prepared - 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, 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 \u003d Hg (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 impregnated with alcohol. A hole is made in the center of the cone and a mixture of 2 g is placed there. baking soda and 13 g of powdered sugar. Burn alcohol. Caxap turns into caramel, and soda decomposes with the release of 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 calcium chloride, manganese (II), cobalt (II), nickel (II) and other metals are thrown to 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 snow, 1-2 pieces of calcium carbide are placed in a jar. After that, a burning splinter is brought to the jar. The snow flares up and burns with a smoky flame. The reaction takes place between calcium carbide and water:
CaC 2 + 2H 2 O \u003d Ca (OH) 2 + C 2 H 2
The escaping gas - acetylene burns:
2C 2 H 2 + 5O 2 \u003d 4CO 2 + 2H 2 O.
"Buran" in a glass.Pour 5 g of benzoic acid into a 500 ml beaker and put a sprig of pine. Close the glass with a porcelain cup cold water and heated over an alcohol lamp. The acid first melts, then turns into steam, and the glass is filled with white "snow" that covers the twig.
Secondary school No. 35
Novomikhailovsky settlement
municipality
Tuapse district
Entertaining experiences on the subject
"Chemistry in Agriculture"
Teacher:
Kozlenko
Alevtina Viktorovna
2015
Different ways to get "milk".Solutions are prepared for the experiment: sodium chloride and silver nitrate; barium chloride and sodium sulfate; calcium chloride and sodium carbonate. Pour these solutions into separate beakers. In each of them, “milk” is formed - insoluble white salts:
NaCI + AgNO 3 \u003d AgCI ↓ + NaNO 3;
Na 2 SO 4 + ВаСI 2 \u003d BaSO 4 ↓ + 2NaCI;
Na 2 CO 3 + CaCI 2 \u003d CaCO 3 ↓ + 2NaCI.
Turning milk into water.An excess of hydrochloric acid is added to a white precipitate obtained by pouring solutions of calcium chloride and sodium carbonate. The liquid boils and becomes colorless and
transparent:
CaCl 2 + Na 2 CO 3 \u003d CaCO 3 ↓ + 2NaCl;
CaCO3↓ + 2HCI = CaCI 2 + H 2 O + CO 2.
original egg. AT glass jar with dilute hydrochloric acid solution egg. After 2-3 minutes, the egg is covered with gas bubbles and floats to the surface of the liquid. The gas bubbles break off 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
Novomikhailovsky settlement
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. What chemical element discovered earlier on the Sun than on Earth?
3. What rare metal is included in some precious stones?
4. What is helium air?
5. What metals and alloys are melted into 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 kind of molten metal can freeze water /?
14. Is drinking clean water good for a person?
15. Who was the first to determine the quantitative chemical composition water?
16 . What gas is in the solid state at a temperature - 2>252 °C combines with an explosion with liquid hydrogen?
17. What element is the basis of the entire mineral world of the Nanki planet?
18. Which compound of chlorine and mercury is a strong poison?
19. The names of what elements are associated with radioactive processes?
Answers:
1. The following elements are most common in the earth's crust: oxygen, silicon, aluminum, iron, calcium, sodium, magnesium, potassium, hydrogen, titanium. These elements occupy approximately 96.4% of the mass of the earth's crust; for all other elements, only 3.5% of the mass of the earth's crust remains.
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 component precious stones (beryl, aquamarine, alexandrite, etc.).
4. This is the name of artificial air, which includes approximately 20% oxygen and 80% helium.
5. The following metals melt in hot water: cesium (+28.5 °С), gallium (+ 29.75 °С), rubidium (+ 39 °С), potassium (+63 °С). Wood's alloy (50% Bi, 25% Pb, 12.5% Sn, 12.5% Cd) melts at +60.5°C.
6. The most refractory metals such as: tungsten (3370 ° C), rhenium (3160 ° C), tantalum (3000 ° C), osmium (2700 ° C), molybdenum (2620 ° C), niobium (2415 ° C).
7. Heavy water is the compound of the hydrogen isotope of deuterium with oxygen D 2 A. There is a small amount of heavy water in ordinary water (1 part by weight in 5000 parts by weight).
8. The composition of the human body includes 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
others
9. The heaviest gas taken under normal conditions is tungsten hexafluoride WF 6 , the heaviest liquid is mercury, the heaviest solid- osmium metal Os.
10. Approximately 50 chemical elements are used in the manufacture of a car, 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. Copper and iron sulfates, barium and zinc chlorides are used to protect plants from pests and diseases.
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 doesn't have useful salts and gases. It flushes out the salts contained in the cell sap from the cells of the stomach.
15. The quantitative chemical composition of water, first by the method of synthesis, and then by analysis, was determined by Lavoisier.
16. Fluorine - 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 the combination of chlorine with mercury - sublimate. In medicine, sublimate is used as disinfectant (1:1000).
19. The names of such elements are associated with radioactive processes: astatine, radium, radon, actinium, protactinium.
Do you know that...
The production of 1 ton of building bricks requires 1-2 m 3 water, and for the production of 1 ton of nitrogen fertilizers and 1 ton of capron - respectively 600, 2500 m 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 a temperature of 0 ° C, it would be distributed over the earth's surface in a thin layer of 2-3 mm. Ozone upper layers atmosphere absorbs most ultraviolet radiation that the sun sends, and protects all living things from its destructive influence.
Polycarbonate is a polymer interesting features. It can be hard like metal, elastic like silk, transparent like crystal, or dyed different colors. The polymer can be molded. It does not burn, 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. At a concentration in the air of more than 1%, its smell is extremely unpleasant and it is impossible to breathe it.
Crystal table salt with slow crystallization, it 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, as it interacts with it and continues to burn due to the released oxygen.
The most refractory metal is tungsten (t pl 3410 ° C), and the most fusible metal is cesium (t pl 28.5 °С).
The largest gold nugget found in the Urals in 1837 weighed about 37 kg. A gold nugget of 108 kg was found in California, and 250 kg in Australia.
Beryllium is called the metal of indefatigability, because the springs made from its alloy can withstand up to 20 billion load cycles (they are almost eternal).
CURIOUS FIGURES AND FACTS
Freon substitutes. Freons and other synthetic substances containing chlorine and fluorine are known to destroy the ozone layer of the atmosphere. Soviet scientists found a replacement for freon - hydrocarbon propylanes (compounds of propane and butane), harmless to the atmospheric layer. By 1995 chemical industry will produce 1 billion aerosol packages.
TU-104 and plastics. The TU-104 aircraft has 120,000 parts made of organic glass, other plastics and their various combinations 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 take place:
N 2 + O 2 \u003d 2NO
2NO+O 2 \u003d 2NO 2
2NO 2 + H 2 O + 1 / 2O 2 \u003d 2HNO 3
Thus, nitrate ions enter the soil, which are absorbed by plants.
Methane and warming. The methane content in the lower layers of the 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 the content of methane in the troposphere contributes to an increase in greenhouse effect because methane molecules absorb infrared radiation.
Ashes in sea water. In the water of the seas and oceans there are dissolved salts of gold. 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 sea water. 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”. Gak is a powder of amorphous silicon dioxide, which is used as a filler for rubber in the manufacture of rubber from it.
Threat from trace elements. Active circulation accumulating in natural environments trace elements poses, according to experts, a serious threat to health modern man and future generations. Their sources are millions of tons of annually burned fuel, blast furnace production, non-ferrous metallurgy, mineral fertilizers applied to the soil, etc.
Transparent rubber.In the manufacture of rubber from rubber, zinc oxide is used (it speeds up the vulcanization process of rubber). If zinc peroxide is added to rubber instead of zinc oxide, then the rubber is transparent. Through a layer of such rubber 2 cm thick, you can freely read a book.
Oil is more precious than gold.Rose oil is required to make many types of perfume. It is a mixture of aromatic substances extracted from rose petals. To obtain 1 kg of this oil, 4-5 tons of petals must be collected and subjected to chemical treatment. Rose oil is filtered three times more expensive than gold.
Iron is within us.The body of an adult contains 3.5 g of iron. This is very little compared, for example, with calcium, which 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 main mass of iron, which is part of the body (2.45 g), is concentrated in blood erythrocytes. Iron is found in the 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 male can store up to 1 g of iron. Between all tissues and organs containing iron, there is a constant exchange. About 10% of iron is brought into the bone marrow by the blood. It is part of the pigment that colors the hair.
Phosphorus - the 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 in the bones, about 130 g is in the muscles, and 12 g is in the nerves and brain. Almost all physiological processes occurring in our body are associated with the transformation 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 the 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 noticeably change the properties of the alloys. This is due to segregation, i.e., the formation of an excess concentration of alloying elements on structural defects.
Types of coal. "Colorless Coal"- this is gas, "yellow coal" - solar energy, "green coal" - vegetable fuel, "blue coal" - the energy of the ebb and flow of the seas, "blue coal" - driving force wind, "red coal" - the energy of volcanoes.
Native aluminium.Recent discoveries of native metallic aluminum have raised the question of how it was formed. According to scientists, in natural melts under the influence of electrotelluric currents (electric currents flowing in the earth's crust), aluminum is reduced electrochemically.
Plastic nail.Plastic masses - polycarbonates were also suitable for the manufacture of nails. Nails from them are freely driven into the board and do notrust, in many cases perfectly replacing 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, 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 daily carries into the sea up to 20 liters of "volcanic" sulfuric acid. IN THE USSR sulphuric acid was discovered by academician Fersman in the sulfur deposits in the Karakum desert.
Fun chemistry games
Who is faster and more?The teacher invites the participants of the game to write the names of the elements ending in the same letter, for example, in “n” (argon, krypton, xenon, lanthanum, molybdenum, neon, radon, etc.). The game can be made more difficult by offering to find these elements in the 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 blackboard and asks him to write down a series of syllables. The rest of the students write them in their notebooks. Task: in 3 minutes, make possible names of elements from the recorded syllables. For example, from the syllables "se, tiy, diy, ra, lion, li" you can compose the words: "lithium, sulfur, radium, selenium."
Drawing up reaction equations.“Who can quickly write equations for reactions, for example, between a metal and oxygen? - asks the teacher, referring to the participants in the game. - Write down the equation for the oxidation of aluminum. 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 some group of elements (or period) and in turn invites the teams to name and write the signs of the elements of a closed group (or period). The winner is the student who names the most chemical elements and correctly writes their signs.
The meaning of the names of elements in translation from a foreign language.What does the word "bromine" mean in Greek? You can play the same game and find out by the participants the meaning of the names of the elements translated from Latin (for example, ruthenium, tellurium, gallium, hafnium, lutetium, holmium, etc.).
Name the formula. The teacher names some compound, for example, magnesium hydroxide. The players, in whose hands are tablets with formulas, run out, holding a tablet with the corresponding formula in their hands.
Charades, puzzles,
chainwords, crosswords.
1 . The first four letters of the name of the famous Greek philosopher" denote the word "people" in Greek without last letter, the last four are an island in the Mediterranean; in general - the name of the Greek philosopher, founder of the atomistic 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 won the Nobel Prize.(Radon, rhodium - radium.)
3. The first syllable of the name of the 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. Sklodowska-Curie; in general it is (in alchemical language) "the gall of the god Vulcan".(Selenium, radium - sulfur.)
4. The first syllable of the name is also the first syllable of the name of an asphyxiant gas obtained by the synthesis of carbon monoxide (II) and chlorine; the second syllable is the first in the name of the 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.)
Did you know that May 29 is Chemist's Day? Which of us in childhood did not dream of creating peculiar magic, amazing chemical experiments? It's time to turn your dreams into reality! Read on and we will tell you how to have fun Chemist Day 2017, as well as what chemistry experiments for kids are easy to do at home.
home volcano
If you are no longer attracted, then ... Want to see a volcanic eruption? Try making it at home! To arrange a chemical experiment "volcano" you will need soda, vinegar, food coloring, a plastic cup, a glass of warm water.
Pour 2-3 tablespoons of table soda into a plastic cup, add ¼ cup of warm water and a little food coloring, preferably red. Then add ¼ of vinegar and watch the "eruption" of the volcano.
Rose and ammonia
A very interesting and original chemical experiment with plants can be viewed on a video from YouTube:
self-inflating balloon
Do you want to conduct safe chemistry experiments for children? Then you will definitely like the balloon experiment. Prepare in advance: a plastic bottle, baking soda, balloon and vinegar.
Pour 1 teaspoon of baking soda inside the ball. Pour ½ cup of vinegar into the bottle, then put the ball on the neck of the bottle and make sure that the soda gets into the vinegar. As a result of a violent chemical reaction, which is accompanied by the active release of carbon dioxide, the balloon will begin to inflate.
pharaoh snake
For the experiment you will need: calcium gluconate tablets, dry fuel, matches or gas-burner. See the YouTube video for the steps:
color magic
Do you want to surprise a child? Rather, conduct chemical experiments with color! You will need the following available ingredients: starch, iodine, a transparent container.
Mix white starch and brown iodine in a container. As a result, you will get an amazing mixture of blue.
We grow a snake
The most interesting home chemistry experiments can be done using available ingredients. To create a snake, you will need: a plate, river sand, powdered sugar, ethyl alcohol, a lighter or burner, baking soda.
Pour a sand slide onto a plate and soak it with alcohol. In the top of the slide, make a recess where you carefully add powdered sugar and soda. Now we set fire to the sand hill and observe. After a couple of minutes, a dark wriggling ribbon will begin to grow from the top of the hill, which resembles a snake.
How to conduct chemical experiments with an explosion, see the following video from Youtube:
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There are very simple experiences that children remember for a lifetime. The guys may not fully understand why this is all happening, but when time will pass and they will find themselves in a lesson in physics or chemistry, a very clear example will surely pop up in their memory.
website collected 7 interesting experiments that children will remember. Everything you need for these experiments is at your fingertips.
refractory ball
It will take: 2 balls, candle, matches, water.
An experience: Inflate a balloon and hold it over a lighted candle to show the children that the balloon will burst from fire. Then pour plain tap water into the second ball, tie it up and bring it to the candle again. It turns out that with water the ball can easily withstand the flame of a candle.
Explanation: The water in the balloon absorbs the heat generated by the candle. Therefore, the ball itself will not burn and, therefore, will not burst.
Pencils
You will need: plastic bag, pencils, water.
An experience: Pour water halfway into a plastic bag. We pierce the bag through with a pencil in the place where it is filled with water.
Explanation: If you pierce a plastic bag and then pour water into it, it will pour out through the holes. But if the bag is first filled halfway with water and then pierced sharp object so that the object remains stuck in the bag, then almost no water will flow out through these holes. This is due to the fact that when polyethylene breaks, its molecules are attracted closer to each other. In our case, the polyethylene is pulled around the pencils.
Non-popping ball
You will need: balloon, wooden skewer and some dishwashing liquid.
An experience: Lubricate the top and bottom with the product and pierce the ball, starting from the bottom.
Explanation: The secret of this trick is simple. In order to save the ball, you need to pierce it at the points of least tension, and they are located at the bottom and at the top of the ball.
Cauliflower
It will take: 4 cups of water, food coloring, cabbage leaves or white flowers.
An experience: Add food coloring of any color to each glass and put one leaf or flower into the water. Leave them overnight. In the morning you will see that they have turned into different colors.
Explanation: Plants absorb water and thus nourish their flowers and leaves. This is due to the capillary effect, in which the water itself tends to fill the thin tubes inside the plants. This is how flowers, and grass, and big trees. By sucking in tinted water, they change their color.
floating egg
It will take: 2 eggs, 2 glasses of water, salt.
An experience: Gently place the egg in a glass of plain clean water. As expected, it will sink to the bottom (if not, the egg may be rotten and should not be returned to the refrigerator). Pour warm water into the second glass and stir 4-5 tablespoons of salt in it. For the purity of the experiment, you can wait until the water cools down. Then dip the second egg into the water. It will float near the surface.
Explanation: It's all about density. The average density of an egg is much greater than that of plain water, so the egg sinks down. And the density of the saline solution is higher, and therefore the egg rises.
crystal lollipops
It will take: 2 cups water, 5 cups sugar wooden sticks for mini-kebabs, thick paper, transparent glasses, a saucepan, food coloring.
An experience: In a quarter cup of water, boil sugar syrup with a couple of tablespoons of sugar. Sprinkle some sugar on paper. Then you need to dip the stick in syrup and collect the sugar with it. Next, distribute them evenly on a stick.
Leave the sticks to dry overnight. In the morning, dissolve 5 cups of sugar in 2 cups of water on fire. You can leave the syrup to cool for 15 minutes, but it should not cool down much, otherwise the crystals will not grow. Then pour it into jars and add different food colors. Lower the prepared sticks into a jar of syrup so that they do not touch the walls and bottom of the jar, a clothespin will help with this.
Explanation: As the water cools, the solubility of sugar decreases, and it begins to precipitate and settle on the walls of the vessel and on your stick with a seed of sugar grains.
lit match
Need: Matches, flashlight.
An experience: Light a match and hold it at a distance of 10-15 centimeters from the wall. Shine a flashlight on the match and you will see that only your hand and the match itself are reflected on the wall. It would seem obvious, but I never thought about it.
Explanation: Fire does not cast shadows, as it does not prevent light from passing through it.
