We have a new set for fans chemical experiments from the "Super Professor" series. This time we have to watch a volcanic eruption and pharaoh snakes.

Important! These experiments should only be carried out in nature - there is a lot of fire and ashes!

And about our experiments that we carried out at home, see the articles ““”.

This time we decided to start our chemical experiments by reviving pharaoh snakes.

Qiddycome: Series “Best Chemistry Experiences and Experiments: Pharaoh's Snake”

For this chemical experiment we needed:

• Evaporation bowl
• Dry fuel
• Matches
• Scissors (or tweezers)
• Calcium gluconate – 3 tablets
• Gloves

Conducting the chemical experiment “Pharaoh’s Snakes”

1. We put a tablet of dry fuel into the bowl and set it on fire.
2. Using tweezers, carefully place the calcium gluconate tablet on the fire.

The tablet turns into a Pharaoh's snake, which crawls out of the bowl and grows until it crumbles into ashes.

Calcium gluconate should be placed in the center of the burning tablet, then the pharaoh’s snakes will be fat :) We first put one calcium gluconate tablet in the center, and two at the edges, and in the video you can see how the snakes differ in size. Then we moved the calcium gluconate to the center and all the pharaoh's snakes began to flow merrily.

Watch the video of how Pharaoh's snakes crawl:

Scientific explanation of the Pharaoh's Serpents chemical experiment

When calcium gluconate decomposes, calcium oxide, carbon, carbon dioxide and water are formed. The volume of decomposition products is much larger than the volume of the original product, which is why such an interesting effect is obtained.

In the “Super Professor” set, the ingredients are designed to repeat the “Pharaoh’s Snakes” chemical experiment three times.

Qiddycome: Series “The best chemical experiences and experiments: Vulcan”

Like most blog moms, Olesya and I made a volcano out of soda and vinegar several times. I thought there would be something similar in the box. But I was very wrong. The eruption experiment here was completely different - much cooler!

For the Vulcan experiment we used:

• Evaporation bowl
• Foil (non-flammable heat-resistant material)
• Ammonium dichromate (20 g)
• Potassium permanganate (10 g)
• Glycerin – 5 drops
• Pipette
• Gloves

Carrying out the chemical experiment “Vulcan”

1. Place foil on the table and place the evaporation bowl on it.
2. Pour ammonium dichromate (half a jar) into a bowl and make a depression at the top of the slide.
3. Pour potassium permanganate into the recess.
4. Take a few drops of glycerin and drop it onto potassium permanganate.

A few minutes later our volcano caught fire. Myself! No burning!

Here is a video of our burning volcano:

Scientific explanation of the chemical experiment "Vulcan".

It turns out that ammonium dichromate burns on its own if you set it on fire. But in our experiment, a mixture of potassium permanganate and glycerin worked as a fuse. Due to the reaction of this mixture, heat began to be released, which led to the ignition of ammonium dichromate.

Burning volcano eruption - amazing chemical experiment ! More interesting than an experiment We probably haven’t done it yet!

Olga Happy Category: 6 comments

Chemical experiment volcano at home

Hello, dear readers! It's no secret that all children love the mysterious, beautiful and magical. Probably, your children also like everything fabulous and interesting? Wouldn't you like to play the role of a wizard for your baby? Surprise him with unusual phenomena, make a lasting impression?

I bring to your attention the experiments at home that we conduct with children. Today I will tell you about the Vulcan experience for children- this is an amazing, mesmerizing spectacle, children watch the volcanic eruption with interest, I recommend trying it. Your baby will definitely appreciate it!

In addition to this experiment, the kids and I conducted several more: an experiment with milk (you can watch) and an experiment with water (see), which I think your child will also appreciate!

1. Cardboard
2. Plasticine
3. Jar (I took it from baby puree)
4. Plate or tray
5. Stapler
6. Scissors
7. Dishwashing liquid 1 tbsp.
8. Soda 1 tbsp.
9. Acetic acid
10. Thinned paint

Making preparations for the Vulcan experiment

Experience at home Vulcan

Now I will tell you in detail how to do the volcano experience. By the way, during the experiment, the children took an active part - they covered a paper cone with plasticine, poured soda into a jar, poured detergent, colored the water with paints, after which the resulting colored solution was poured into a jar. The only thing I did myself was to cut out a cone, fasten it with a stapler and pour vinegar into the mouth of the volcano, after which the eruption began. So, let's proceed directly to the experiment.

Seems like quite a lot interesting ideas suggested in the next section.

I wish I could mix cola and mentos

The chemical elements that make up everything that exists can form incredible compounds. They have unique properties and participate in the synthesis of essential substances used in industry. One such compound is potassium dichromate, which this article will discuss.

Physical properties

Potassium dichromate has many faces. The chemical formula of this substance is K 2 Cr 2 O 7. It has several names. The technical name of the reagent is chrompic. Sometimes K 2 Cr 2 O 7 is found under the name “potassium dichromate”.

At room temperature the substance is orange crystals with a specific density of 2.68 g/cm 3 . If you look closely, you will notice their triclinic structure. Like many other compounds, with increasing temperature the crystal lattice of chromium peak changes - this is how a monoclinic form is formed. This can be observed after passing the threshold of 257 degrees Celsius.

The compound boasts good solubility in water. As the temperature rises, it increases. At 20 ⁰C in liquid state 12.5 grams of the substance will be transferred, and when boiling - 100 g. Chromium is insoluble in alcohol and ammonia, but reacts with hydrogen fluoride.

The melting point is quite low and is only 396 ⁰C. At 610 ⁰C, complete thermal decomposition occurs with the formation of K 2 CrO 4, chromium (III) trioxide and oxygen.

Preparation and purification

To obtain K 2 Cr 2 O 7, a solution of sodium chromium and potassium chloride is used. They are mixed and subjected to strong heating to a temperature of 1200 ⁰C. Under such conditions, the exchange reaction occurs:

2KCl+Na 2 CR 2 O 7 → K 2 Cr 2 O 7 +2NaCl

To purify crystals in laboratory conditions, the recrystallization method is used. Prepare a solution by diluting 100 grams of potassium dichromate in 1 liter hot water. It is thoroughly mixed, filtered and evaporated so that about 1/7 of the original volume remains. The residue is cooled with constant stirring. In this way, small crystals are formed, which must be filtered under draft using a Buchner funnel. The process requires three rinses with very cold water.

Three-fold recrystallization will allow you to obtain a sample with a potassium dichromate reagent content of 99.92 to 100%. To achieve such purity, prepare a solution of 100 grams of the drug and 150 ml of boiling water. It is mixed well and poured in a thin stream into a desiccator or porcelain cup. As it cools, crystals form and are filtered on a porous glass funnel or platinum cone. Drying is carried out at 100 ⁰C for 2-2.5 hours. The resulting solid formation is crushed and continued to be heated at 200 ⁰C for another 12 hours. This sequence of actions is repeated 3 times.

Oxidative properties

One of the strongest oxidizing agents is potassium dichromate. Chemical properties This substance can be observed in the following experiments:

• When a porcelain cup with a small amount of reagent is heated strongly, its crystals turn into a dark-colored melt. After cooling, the calcined residue acquires green tint, and the solution of this substance is yellow. What remains on the shard is chromium trioxide, and the liquid phase is K 2 CrO 4 .
• In an alkaline environment, the reagent is reduced to oxides. Dissolve 3 grams of crystals in 50 ml of distilled water. Add some K 2 CO 3 . A reaction will occur with the release of CO 2, the solution will turn yellow - K 2 CrO 4 has been formed. When acid is added, a red-orange dichromate is formed again.
• The reagent is capable of reducing halogens from compounds. Boil 5 ml of K 2 Cr 2 O 7 and 3 ml of hydrochloric acid. The reaction will release free chlorine gas. Chrompic will turn into green trioxide. The experiment is carried out only under strong traction!
• Chromate salts of lead and silver are insoluble. If AgNO 3 is added to K 2 Cr 2 O 7, an exchange reaction occurs with the precipitation of a red-brown precipitate, Ag 2 CrO 4. The same reduction mechanism occurs when reacted with lead nitrate, which produces a yellow insoluble residue.
• The chromium crystals themselves also have oxidizing properties. If they are heated with sulfur, the reagent will reduce it to potassium sulfide and trioxide. Carrying out the same manipulation with carbon, you get K 2 CO 3, CO 2 and chromium (III) oxide.

Experience "Volcano Eruption"

One of the most impressive chemical experiments is the “volcanic eruption.” Its demonstration will require special equipment, aimed at protecting the respiratory system. For the experiment, you will have to cover your skin and wear a respirator, because the product of the reaction will be toxic chromium trioxide, which is harmful to humans.

A small pile of potassium dichromate (an alternative reagent (NH 4) 2 Cr 2 O 7) is placed on a fireproof substrate, which can be an asbestos sheet, tile or crystallizer. Make a hole in the center, add some alcohol and set it on fire. As combustion occurs, chromium decomposes with the formation of oxygen. The gas is included in the reaction and provides the blue flame effect. It's raging on the laboratory table real volcano! The remaining combustion products will be K 2 CrO 4 and chromium (III) trioxide. These substances are very toxic and cause burns and ulcerations if they come into contact with the skin.

"Pharaoh's Snake"

No less interesting is the experiment called “Pharaoh’s snakes” using the potassium dichromate reagent. Reactions with its participation look impressive: solutions change color, crystals decompose to form green-colored oxide Cr 2 O 3.

To get a “snake,” grind a mixture of equal parts of chromium and sugar in a mortar and add half a portion of sodium nitrate. Moisten all ingredients and mix in a little collodion. Take a glass tube and press the pulp into it. Set fire to one end of the vessel and you will see a black “snake” begin to crawl out of the other. When it cools down, it will turn color green color. In this case, sucrose burns to carbon, sodium nitrate decomposes to form O 2 and NaNO 2, and chromium forms trioxide.

Growing Crystals

If you prepare a saturated solution of potassium dichromate, you can grow fantastic crystals. They look very impressive, and making such beauty is very simple. It is enough to place the glass with the hot solution in a place protected from light, vibration and draft. Place a string inside the container and secure it to the edge. You need to wait a few days and you will see red-orange crystals forming on the thread.

Industrial Applications

Potassium dichromate has found application in several industries. It is used in the production of pigments for paint and varnish products, for tanning leather, and disinfecting seeds. The oxidizing properties make it possible to use chromium for creating match heads, combating metal corrosion, making pyrotechnic products and dry electrolytes.

A mixture of the reagent with concentrated sulfuric acid is an ideal means for washing chemical dishes.

"And you, Vulcan, who are before the forges
You forge lightning in the bottom of hell!"
(G.R. Derzhavin, “To the Knight of Athens”)

The most famous of the "domestic" volcanoes - dichromate - was first observed by the German chemist Rudolf Böttger, who became famous as the inventor of modern matches and the explosive pyroxylin.

Böttger Volcano

In 1843 Rudolf Böttger received ammonium dichromate(NH 4) 2 Cr 2 O 7 is an orange-red crystalline substance. He decided to test this substance. Having poured a pile of crystals onto a plate, he brought a burning splinter to it. The crystals did not flare up, but something “boiled” around the end of the burning splinter, and hot particles began to rapidly fly out. The hill began to grow and soon took on impressive dimensions. The color also changed: instead of orange it became green. Later it was found that ammonium dichromate spontaneously decomposes not only from a lit splinter or match, but also from a heated glass rod. This releases nitrogen gas, water vapor, solid particles of hot chromium oxide and a large number of warmth. An intramolecular redox reaction occurs.

Volcano Lemery

The French chemist, pharmacist and physician Nicolas Lemery (1645-1715) also observed something similar to a volcano in his time when, having mixed 2 g of iron filings and 2 g of powdered sulfur in an iron cup, he touched it with a hot glass rod. After some time, black particles began to fly out of the prepared mixture, and the mixture itself, having greatly increased in volume, became so hot that it began to glow. Lemery Volcano is the result of a simple chemical reaction between iron and sulfur to form iron sulfide. This reaction proceeds very energetically and is accompanied by significant heat release.

Ferrate volcano

To demonstrate this experiment, which is also very effective, mix 1 g of iron powder or powder with 2 g of dry potassium nitrate, previously ground in a mortar. The mixture is placed in the recess of a slide made from 4-5 tablespoons of dry sifted river sand, moisten ethyl alcohol or cologne and set it on fire. A violent reaction begins with the release of sparks, brownish smoke and strong heating. When potassium nitrate interacts with iron, potassium ferrate and gaseous nitrogen monoxide are formed, which, when oxidized in air, produces brown gas - nitrogen dioxide. If the solid residue after the end of the reaction is placed in a glass of cold boiled water, a red-violet solution of potassium ferrate will be obtained.

All three volcanoes will look especially impressive if shown in the evening twilight outdoors. And if you are doing “chemical volcanology” indoors, take care of the safety of spectators by seating them away from the demonstration table: inhalation of products"volcanic" reactions very bad! You can't bend over over the “volcano” and touch it until the process is over and all the substances have cooled down!!!

Safe volcano

To prepare a volcano that is completely safe and yet very effective, you will need plate, plasticine, baking soda(sodium bicarbonate), acetic acid(you can use table vinegar - 3 - 9% acetic acid solution), dye(you can take fucorcin from a home medicine cabinet or red food coloring, or even beet juice), any dishwashing liquid.

The plasticine is divided into two parts and one of them is rolled out into a flat “pancake” - the base of the volcano, and from the second a hollow cone is molded with a hole at the top (the slopes of the volcano). Having pinched both parts at the edges, you need to pour water inside and make sure that the “volcano” does not let it through from below. The volume of the internal cavity of the “volcano” should not be very large (100-200 ml is best, this is the capacity of a tea cup or a regular glass). The volcano on a plate is placed on a tray.

To “charge” a volcano with “lava”, prepare a mixture dishwashing liquid(1 tablespoon), dry baking soda(1 tablespoon) and dye(a few drops are enough). This mixture is poured into the “volcano”, and then added there vinegar(quarter cup). A violent reaction begins with the release of carbon dioxide. Brightly colored foam emerges from the crater of the volcano...
After the experiment, do not forget to wash the plate thoroughly.