Do we know everything about salt? Alkali metals and their compounds White salt a was dissolved in water.

Catalog of tasks.
Task 22. Chemical properties of simple and complex substances

Given substances: , .

Using water and the necessary substances only from this list, obtain iron(II) hydroxide in two stages. Describe the signs of the reactions being carried out. For an ion exchange reaction, write the abbreviated ionic equation for the reaction.

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Given substances: . Using water and the necessary substances only from this list, obtain manganese(II) hydroxide in two stages. Describe the signs of the reactions being carried out. For an ion exchange reaction, write the abbreviated ionic equation for the reaction.

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Substances are given: Using water and the necessary substances only from this list, obtain metallic copper in two stages. Describe the signs of the reactions being carried out. For an ion exchange reaction, write the abbreviated ionic equation

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Given substances:

Using water and the necessary substances only from this list, you will obtain bromine in two stages without using electric current. Describe the signs of ongoing reactions. For the ion exchange reaction, the abbreviated ion reaction equation is used.

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Given substances:

Using water and non-hot substances only from this list, obtain copper(II) chloride in two stages. Describe the signs of my reactions. For the second reaction, here is the abbreviated ion reaction equation.

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Substances are given: Using water and the necessary substances only from this list, obtain iron(II) hydroxide in two stages. Describe the signs of the reactions being carried out. For an ion exchange reaction, write the abbreviated ionic equation for the reaction.

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Substances are given: Using water and the necessary substances only from this list, obtain copper (II) hydroxide in two stages. Describe the signs of the reactions being carried out. For an ion exchange reaction, write the abbreviated ionic equation.

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Substances are given: Using water and the necessary substances only from this list, obtain copper(II) hydroxide in two stages. Describe the signs of the reactions being carried out. For an ion exchange reaction, write the abbreviated ionic equation for the reaction.

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The following reagents were proposed for the experiment: hydrochloric acid, solutions of sodium hydroxide, sodium nitrate, barium nitrate, iron (II) sulfate. Using the necessary substances only from this list, obtain iron (II) hydroxide as a result of two successive reactions.

Describe the signs of the reactions being carried out. For the second reaction, write the abbreviated ionic equation.

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The following reagents were proposed for the experiment: zinc (granulated), copper (II) oxide, ammonia solution, zinc sulfate solution, hydrochloric acid. Using the necessary substances only from this list, obtain zinc oxide as a result of two successive reactions.

Describe the signs of the reactions being carried out. For the first reaction, write the abbreviated ionic equation.

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The following reagents are proposed for the experiment:

solutions:

Using water and the necessary substances only from this list, obtain calcium nitrate in two stages. Describe the signs of the reactions being carried out.

For the second reaction, write the abbreviated ionic equation.

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Given substances:. Using water and the necessary substances only from this list, obtain copper(II) nitrate in two stages. Describe the signs of the reactions being carried out. For the second reaction, write the abbreviated ionic equation for the reaction.

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The following reagents are proposed for the experiment: solutions Using the necessary substances only from this list, obtain a solution of iron(II) nitrate as a result of two successive reactions. Write down the equations of the chemical reactions carried out. Describe the signs of these reactions. For the second reaction, write the abbreviated ionic equation.

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Substances are given: Using water and the necessary substances only from this list, obtain iron(II) hydroxide in two stages. Write down the equations of the chemical reactions carried out. Describe the signs of these reactions. For an ion exchange reaction, write the abbreviated ionic equation for the reaction.

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For the pro-ve-de-tion of ex-peri-men-ta, the following re-ak-ti-you are suggested: solutions of potassium nit-ra-ta , hydro-rock-si-da potassium, sul-fa-ta mag-nium, chlor-ri-da barium and chlor-ri-da na-trium. Using inappropriate substances only from this list, in the re-zul-ta-te pro-ve-de-tion two subsequent reactions of potassium chloride solution.

Make a scheme of transformations, as a result of which you can obtain the specified substance. Write down the equations of two reactions. For the first reaction, create an abbreviated ionic equation.

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The following reagents were proposed for the experiment: aluminum and solutions of ammonia, barium chloride, hydrogen peroxide, aluminum sulfate, hydrochloric acid. Using the necessary substances only from this list, obtain a solution of aluminum chloride as a result of two successive reactions.

Draw up a scheme of transformations as a result of which the indicated substance can be obtained. Write down the equations for the two reactions. For the second reaction, write the abbreviated ionic equation.

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Substances are given: Using water and the necessary substances only from this list, obtain iron(III) hydroxide in two stages. Write down the equations of the chemical reactions carried out. Describe the signs of these reactions. For an ion exchange reaction, write the abbreviated ionic equation for the reaction.

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The following reagents were proposed for the experiment: phenolphthalein solutions. Using the necessary substances only from this list, obtain a solution of sodium chloride as a result of two successive reactions. Write down the equations of the chemical reactions carried out. Describe the signs of these reactions. For the second reaction, write the abbreviated ionic equation.

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Substances are given: Using water and the necessary substances only from this list, obtain magnesium nitrate in two stages. Write down the equations of the chemical reactions carried out. Describe the signs of these reactions. For the second reaction, write the abbreviated ionic equation for the reaction.

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The substances are given: solutions and ammonia. Using water and the necessary substances only from this list, obtain an ammonium chloride solution in two stages. Write down the equations of the chemical reactions carried out. Describe the signs of these reactions. For the second reaction, write the abbreviated ionic equation for the reaction.

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Substances are given: solution Using water and the necessary substances only from this list, obtain a solution of zinc chloride in two stages. Write down the equations of the chemical reactions carried out. Describe the signs of these reactions. For the second reaction, write the abbreviated ionic equation for the reaction.

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Substances are given: Using water and the necessary substances only from this list, obtain calcium bicarbonate in two stages. Write down the equations of the chemical reactions carried out. Describe the signs of these reactions. For the first reaction, write the abbreviated ionic equation.

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The following reagents are proposed for the experiment: solutions: Using water and the necessary substances only from this list, obtain silver chloride in two stages. Write down the equations of the chemical reactions carried out. Describe the signs of these reactions. For the second reaction, write the abbreviated ionic equation.

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The substances are given: solution and ammonia solution. Using water and the necessary substances only from this list, obtain iron(III) oxide in two stages. Write down the equations of the chemical reactions carried out. Describe the signs of these reactions. For an ion exchange reaction, write the abbreviated ionic equation for the reaction.

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Substances are given: Using water and the necessary substances only from this list, obtain zinc nitrate in two stages. Write down the equations of the chemical reactions carried out. Describe the signs of these reactions. For an ion exchange reaction, write the abbreviated ionic equation for the reaction.

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The following reagents are proposed for the experiment: solutions: Using water and the necessary substances only from this list, obtain iron(III) hydroxide in two stages. Write down the equations of the chemical reactions carried out. Describe the signs of these reactions. For an ion exchange reaction, write the abbreviated ionic equation.

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Given substances: Using water and the necessary substances only from this list, obtain copper(II) chloride in two stages. Write down the equations of the chemical reactions carried out. Describe the signs of these reactions. For the second reaction, write the abbreviated ionic equation for the reaction.

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Given substances: litmus solution. Using water and the necessary substances only from this list, obtain a solution of ammonium nitrate as a result of two successive reactions. Write down the equations of the chemical reactions carried out. Describe the signs of these reactions. For the second reaction, write the abbreviated ionic equation.

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Substances are given: solution Using water and the necessary substances only from this list, obtain a solution of iron(II) chloride in two stages. Write down the equations of the chemical reactions carried out. Describe the signs of these reactions. For an ion exchange reaction, write the abbreviated ionic equation for the reaction.

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The following reagents were proposed for the experiment: solutions of sodium chloride, sodium hydroxide, sulfuric acid, barium chloride, metallic iron. Using the necessary substances only from this list, obtain a solution of iron(II) chloride as a result of two successive reactions.

Draw up a diagram of the transformations as a result of which the indicated substance can be obtained. Write down the equations for the two reactions. For the second reaction, write the abbreviated ionic equation.

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Substances are given: Using water and the necessary substances only from this list, obtain zinc sulfide in two stages. Write down the equations of the chemical reactions carried out. Describe the signs of these reactions. For an ion exchange reaction, write the abbreviated ionic equation for the reaction.

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The following reagents are proposed for the experiment: solutions: Using water and the necessary substances only from this list, obtain zinc hydroxide in two stages. Write down the equations of the chemical reactions carried out. Describe the signs of these reactions. For the second reaction, write the abbreviated ionic equation.

Oh salt mia!

We were not mistaken in mentioning the famous Italian song “My Sun!”: many peoples of the world have the same root word for “salt” and “sun”. Salt is mentioned in the Bible about 30 times, and from there the expression “salt of life” came to us.
Salt symbolized wealth and power, protected from evil forces: ancient rulers often sat on a throne made of salt. Many traditions remain from those distant times. Russians greet distinguished guests with bread and salt. Jews celebrating the Sabbath, after washing their hands, break bread and dip it in a salt shaker, distributing it to the whole family. Out of habit, many nations still have a salt shaker on their tables to this day, because previously food was prepared without salt, but salted on the table. And a boring, uninteresting life or person is still called the word “fresh,” which has the opposite meaning of “salty.”

Do we know everything about salt?

Salt or sodium chloride is a white crystalline mineral substance found in nature; dissolves in water; one of the few minerals that people eat. Salt is the most ancient of spices.
For many centuries, salt was a valuable commodity. Wars were fought over salt, states were formed and destroyed. At the end of the Roman Empire and throughout the Middle Ages, salt was a valuable commodity that was transported along the "Salt Roads" to the heartland of the Germanic tribes. Cities, states and principalities through which the “salt route” passed imposed huge taxes on traders for transporting salt through their territory. This marked the beginning of wars, and even caused the founding of some cities, for example, Munich in 1158.

No one will argue that salt is a basic necessity.

There are 300 g of it in the human body.

Every day this supply is consumed, and every day it must be replenished.

Don't think that salt is only necessary for the taste of food. It serves as the material from which hydrochloric acid is formed in the stomach.

Thanks to this acid, food is digested and microbes die. In addition, salt saves us from dehydration by retaining moisture in the body.

Now salt is widely available and we do not value it, but this was not always the case. In the old days, real wars broke out over salt, taxes were paid with it, and peasant revolts were extinguished by the distribution of salt.

In China they even made money from salt. To do this, the brine was boiled until thick, until it took the form of dough. Then they made pies from this “dough”, put the emperor’s mark on them and dried them.

The salt had a very strong effect on different languages. The greatest influence occurred in languages ​​interacting with Roman and Greek civilizations while salt was at a premium.
Roman soldiers were given permission to buy salt (in Latin: sal), salarium argentum, from which the English word salary is derived. The Romans also preferred to salt their greens, resulting in the Latin word for salt becoming part of the new word salad. In barbarian Latin, salata meant “salty.”

In countries where there were no salt deposits, it was mined in some intricate way. For example, Miklouho-Maclay wrote that the Papuans collected pieces of wood that had lain in sea water for a long time, burned them and ate the salted ash.

Salt is obtained in two ways: mining and evaporation of sea water.

Chemical composition various types salts are the same - 99% sodium chloride - but the crystal structure changes greatly. Regular table salt consists of small granules; kosher salt has a much more uneven structure and is larger. Popcorn uses salt that dissolves easily. Rock salt is large pieces of the mineral sodium chloride. The difference in shape and structure allows for different tastes and is useful for different dishes. The speed at which it dissolves is also very important, and the pickling salt must be very fine to dissolve even in cold liquid.

Sea salt, which is made from sea water, also comes in different varieties. Due to the substances in the water, sea salt has a unique taste that is used in many cuisines.

ROCK SALT. This type is probably the most popular and widespread. Solid salt deposits are found in many regions of the world, where they lie at depths ranging from several hundred to more than a thousand meters. Special combines chop salt underground and it is transported to the surface of the earth through conveyors.

There it goes into mills and crumbles to produce particles (crystals) of various sizes. Coarser salt is used mainly for industrial purposes, while finer salt is used for food. Rock salt is distinguished by the lowest content of foreign impurities, low humidity and the highest content of sodium chloride - up to 99%. This means that it will be more saturated than others.

SEDIMENT SALT is formed by the natural evaporation of salt in bodies of water. From geography lessons, everyone remembers the famous salt lakes in the Astrakhan region, Elton and Baskunchak.

Special combines (harvesters) remove the layer of salt on dried lakes and send it along a conveyor for crushing, washing, drying and further processing. Garden salt contains more impurities (clay, sand), and the mass fraction of sodium chloride can be 95-96% (because of this, it often has a grayish appearance).

VACUUM EVAPORATOR SALT. Where salt lies very deep, it is extracted by dissolution. A pipe is placed in the layer of salt and fresh water is pumped into it under high pressure, which dissolves the salt, forming cavities in the deposit. The concentrated brine is then lifted through pipes to the surface, where it is processed and evaporated under vacuum in vats to obtain a highly purified product.

Sometimes the brine raised to the surface is evaporated under the sun in open containers. Salt in deposits is often very pure and requires only minor additional purification.

Evaporation salt is the most expensive and at the same time the most chemically pure and high quality. In our country it is sold under the brand name “Extra”.

Evaporation is also rich in sodium. Therefore, the housewife should pay attention to what kind of salt she uses, and from here calculate its amount.

Since salt is a product that we eat every day in approximately the same quantities, it is increasingly used as a carrier of trace elements. Salt is enriched mainly with iodine and fluorine.

For example, 60% of the salt sold in Germany and 80% of the salt sold in Switzerland are fortified with fluoride. This salt is used to prevent dental diseases. Agree that the effect of toothpaste is much less, its effect is local and very short-term.

In countries where iodine deficiency occurs, salt enriched with iodine is produced. In our body, such salt quickly breaks down and releases iodine, which is necessary for the thyroid gland for the synthesis of thyroid hormones. Consumption of such salt in an amount of 5-6 g per day completely satisfies the body's need for iodine.

Today, the problem of iodine deficiency is very acute. First of all, because of the huge number of people it affects and the possible consequences for individuals and society. In Russia, for example, 98 million people are susceptible to iodine deficiency, more than half of whom are children, adolescents and pregnant women.

Lack of iodine in the diet leads to irreversible changes in the nervous system. Due to damage to the central nervous system, children in areas with low iodine intake develop mental retardation - one of the most severe manifestations of iodine deficiency.

Salt is our main seasoning, and it is necessary for humans, since its natural amount in water and food is not enough for our body.
Do not forget that a person’s needs for table salt depend on energy consumption, climatic conditions, etc. With intense physical activity, a person loses up to 20 grams of salt per day, so in a temperate climate, salt consumption is 10-15 grams per day.

Please note that insufficient or lack of salt impairs the taste of food products. If a person does not receive table salt for a long time, this can cause dizziness, fainting, weakness and other painful phenomena. Excess salt is no less harmful.

Make sure that the taste of the salt is purely salty without any foreign taste or smell. The color of salt (extra) is pure white. For other varieties, shades are allowed: grayish, yellowish and pinkish. There should be no visible contamination.

Store salt in a dry place with relatively high humidity. At lower humidity, it releases moisture to the external environment, i.e. dries out, and at a higher level it moisturizes. Salt is capable of caking and loses its flowability, with fine salt being stronger and coarse salt being weaker. Raw salt cakes more than dry salt.

Iodized salt containing potassium iodide oxidizes in the presence of moisture, air and light, releasing iodine, which then evaporates. There is always moisture in table salt and in the air, which promotes the decomposition of potassium iodide. As iodized salt is stored, the iodine content gradually decreases. It should be stored in a dry place in a closed container. After six months it is considered normal food.

Known deposits

* Artyomovskoye field is the largest in Europe. Extraction in the Artemsol State Production Association mine.
* Baskunchak deposit, production from the lake by JSC Bassol. The Baskunchak Railway was built to export salt.
* Iletsk deposit, production in the mine of JSC Iletsksol
* Odessa estuaries (mining was carried out from 1774 to 1931)
* Elton field Elton

Interesting facts

* Ordinary table salt can serve as a strong poison. On the one hand, it is impossible to live without salt, on the other hand, a dose 10 times higher than usual is lethal. The lethal dose is 3000 milligrams per 1 kilogram of body weight. In other words, for a person weighing 80 kg, you need to use a quarter kilogram pack.

* In countries with cold climates, the daily norm required by the body is significantly lower than in countries with hot climates, due to different types of sweating. Average daily intake for an adult: 3-5 grams of salt in cold countries and up to 20 grams in hot countries.

* In stores, salt consists of up to 97% NaCl, the rest comes from various impurities. Most often, iodates and carbonates are added; in recent years, fluorides have been added more and more often. To prevent dental diseases, use salt with fluoride. Since the 50s, adding fluoride to salt began in Switzerland, and thanks to positive results in the fight against caries in the 80s, fluoride began to be added to salt in France and Germany. Up to 60% of salt sold in Germany and up to 80% in Switzerland is fluoride salt.

* Systematic intake of excess salt compared to the physiological norm leads to an increase in blood pressure. Excessive salt consumption causes heart and kidney diseases.

* In Russia in the 17th century, a Salt Riot occurred, caused by exorbitantly high prices for salt.

Alkali metals react easily with non-metals:

2K + I 2 = 2KI

2Na + H 2 = 2NaH

6Li + N 2 = 2Li 3 N (the reaction occurs at room temperature)

2Na + S = Na 2 S

2Na + 2C = Na 2 C 2

In reactions with oxygen, each alkali metal shows its own individuality: when burned in air, lithium forms an oxide, sodium - peroxide, potassium - superoxide.

4Li + O 2 = 2Li 2 O

2Na + O 2 = Na 2 O 2

K + O 2 = KO 2

Preparation of sodium oxide:

10Na + 2NaNO 3 = 6Na 2 O + N 2

2Na + Na 2 O 2 = 2Na 2 O

2Na + 2NaON = 2Na 2 O + H 2

Interaction with water leads to the formation of alkali and hydrogen.

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

Interaction with acids:

2Na + 2HCl = 2NaCl + H2

8Na + 5H 2 SO 4 (conc.) = 4Na 2 SO 4 + H 2 S + 4H 2 O

2Li + 3H 2 SO 4 (conc.) = 2LiHSO 4 + SO 2 + 2H 2 O

8Na + 10HNO 3 = 8NaNO 3 + NH 4 NO 3 + 3H 2 O

When interacting with ammonia, amides and hydrogen are formed:

2Li + 2NH 3 = 2LiNH 2 + H 2

Interaction with organic compounds:

H ─ C ≡ C ─ H + 2Na → Na ─ C≡C ─ Na + H 2

2CH 3 Cl + 2Na → C 2 H 6 + 2NaCl

2C 6 H 5 OH + 2Na → 2C 6 H 5 ONa + H 2

2CH 3 OH + 2Na → 2 CH 3 ONa + H 2

2СH 3 COOH + 2Na → 2CH 3 COOOONa + H 2

A qualitative reaction to alkali metals is the coloring of the flame by their cations. Li + ion colors the flame carmine red, Na + ion – yellow, K + – violet.

Alkali metal compounds

Oxides.

Alkali metal oxides are typical basic oxides. They react with acidic and amphoteric oxides, acids, and water.

3Na 2 O + P 2 O 5 = 2Na 3 PO 4

Na 2 O + Al 2 O 3 = 2NaAlO 2

Na 2 O + 2HCl = 2NaCl + H 2 O

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

Na 2 O + H 2 O = 2NaOH

Peroxides.

2Na 2 O 2 + CO 2 = 2Na 2 CO 3 + O 2

Na 2 O 2 + CO = Na 2 CO 3

Na 2 O 2 + SO 2 = Na 2 SO 4

2Na 2 O + O 2 = 2Na 2 O 2

Na 2 O + NO + NO 2 = 2NaNO 2

2Na 2 O 2 = 2Na 2 O + O 2

Na 2 O 2 + 2H 2 O (cold) = 2NaOH + H 2 O 2

2Na 2 O 2 + 2H 2 O (hor.) = 4NaOH + O 2

Na 2 O 2 + 2HCl = 2NaCl + H 2 O 2

2Na 2 O 2 + 2H 2 SO 4 (divided horizon) = 2Na 2 SO 4 + 2H 2 O + O 2

2Na 2 O 2 + S = Na 2 SO 3 + Na 2 O

5Na 2 O 2 + 8H 2 SO 4 + 2KMnO 4 = 5O 2 + 2MnSO 4 + 8H 2 O + 5Na 2 SO 4 + K 2 SO 4

Na 2 O 2 + 2H 2 SO 4 + 2NaI = I 2 + 2Na 2 SO 4 + 2H 2 O

Na 2 O 2 + 2H 2 SO 4 + 2FeSO 4 = Fe 2 (SO 4) 3 + Na 2 SO 4 + 2H 2 O

3Na 2 O 2 + 2Na 3 = 2Na 2 CrO 4 + 8NaOH + 2H 2 O

Bases (alkalis).

2NaOH (excess) + CO 2 = Na 2 CO 3 + H 2 O

NaOH + CO 2 (excess) = NaHCO 3

SO 2 + 2NaOH (excess) = Na 2 SO 3 + H 2 O

SiO 2 + 2NaOH Na 2 SiO 3 + H 2 O

2NaOH + Al 2 O 3 2NaAlO 2 + H 2 O

2NaOH + Al 2 O 3 + 3H 2 O = 2Na

NaOH + Al(OH) 3 = Na

2NaOH + 2Al + 6H 2 O = 2Na + 3H 2

2KOH + 2NO2 + O2 = 2KNO3 + H2O

KOH + KHCO 3 = K 2 CO 3 + H 2 O

2NaOH + Si + H 2 O = Na 2 SiO 3 + H 2

3KOH + P 4 + 3H 2 O = 3KH 2 PO 2 + PH 3

2KOH (cold) + Cl 2 = KClO + KCl + H 2 O

6KOH (hot) + 3Cl 2 = KClO 3 + 5KCl + 3H 2 O

6NaOH + 3S = 2Na2S + Na2SO3 + 3H2O

2NaNO 3 2NaNO 2 + O 2

NaHCO 3 + HNO 3 = NaNO 3 + CO 2 + H 2 O

NaI → Na + + I –

at the cathode: 2H 2 O + 2e → H 2 + 2OH – 1

at the anode: 2I – – 2e → I 2 1

2H 2 O + 2I – H 2 + 2OH – + I 2

2H2O + 2NaI H 2 + 2NaOH + I 2

2NaCl 2Na + Cl2

at the cathode at the anode

KNO 3 + 4Mg + 6H 2 O = NH 3 + 4Mg(OH) 2 + KOH

4KClO 3 KCl + 3KClO 4

2KClO3 2KCl + 3O 2

KClO 3 + 6HCl = KCl + 3Cl 2 + 3H 2 O

Na 2 SO 3 + S = Na 2 S 2 O 3

Na 2 S 2 O 3 + H 2 SO 4 = Na 2 SO 4 + S↓ + SO 2 + H 2 O

2NaI + Br 2 = 2NaBr + I 2

2NaBr + Cl 2 = 2NaCl + Br 2

I A group.

1. Electrical discharges were passed over the surface of a caustic soda solution poured into a flask, and the air in the flask turned brown, which disappeared after some time. The resulting solution was carefully evaporated and it was determined that the solid residue was a mixture of two salts. When this mixture is heated, gas is released and the only substance remains. Write the equations for the reactions described.

2. The substance released at the cathode during the electrolysis of molten sodium chloride was burned in oxygen. The resulting product was placed in a gasometer filled with carbon dioxide. The resulting substance was added to the ammonium chloride solution and the solution was heated. Write the equations for the reactions described.

3) Nitric acid was neutralized with baking soda, the neutral solution was carefully evaporated and the residue was calcined. The resulting substance was added to a solution of potassium permanganate acidified with sulfuric acid, and the solution became colorless. The nitrogen-containing reaction product was placed in a solution of sodium hydroxide and zinc dust was added, and a gas with a pungent odor was released. Write the equations for the reactions described.

4) The substance obtained at the anode during the electrolysis of a sodium iodide solution with inert electrodes was reacted with potassium. The reaction product was heated with concentrated sulfuric acid, and the liberated gas was passed through a hot solution of potassium chromate. Write the equations for the reactions described

5) The substance obtained at the cathode during the electrolysis of molten sodium chloride was burned in oxygen. The resulting product was successively treated with sulfur dioxide and a solution of barium hydroxide. Write the equations for the reactions described

6) White phosphorus dissolves in a solution of potassium hydroxide, releasing a gas with a garlicky odor, which spontaneously ignites in air. The solid product of the combustion reaction reacted with caustic soda in such a ratio that the resulting white substance contains one hydrogen atom; when the latter substance is calcined, sodium pyrophosphate is formed. Write the equations for the reactions described

7) An unknown metal was burned in oxygen. The reaction product interacts with carbon dioxide and forms two substances: a solid that reacts with a solution of hydrochloric acid to release carbon dioxide, and a gaseous simple substance that supports combustion. Write the equations for the reactions described.

8) Brown gas was passed through an excess of caustic potassium solution in the presence of a large excess of air. Magnesium shavings were added to the resulting solution and heated, and the resulting gas neutralized the nitric acid. The resulting solution was carefully evaporated, and the solid reaction product was calcined. Write the equations for the reactions described.

9) During the thermal decomposition of salt A in the presence of manganese dioxide, binary salt B and a gas that supports combustion and is part of the air were formed; When this salt is heated without a catalyst, salt B and a salt of a higher oxygen-containing acid are formed. When salt A interacts with hydrochloric acid, a yellow-green gas (a simple substance) is released and salt B is formed. Salt B turns the flame purple, and when it reacts with a solution of silver nitrate, a white precipitate forms. Write the equations for the reactions described.

10) Copper shavings were added to heated concentrated sulfuric acid and the released gas was passed through a solution of caustic soda (excess). The reaction product was isolated, dissolved in water and heated with sulfur, which dissolved as a result of the reaction. Dilute sulfuric acid was added to the resulting solution. Write the equations for the reactions described.

11) Table salt was treated with concentrated sulfuric acid. The resulting salt was treated with sodium hydroxide. The resulting product was calcined with excess coal. The gas released reacted in the presence of a catalyst with chlorine. Write the equations for the reactions described.

12) Sodium reacted with hydrogen. The reaction product was dissolved in water, which formed a gas that reacted with chlorine, and the resulting solution, when heated, reacted with chlorine to form a mixture of two salts. Write the equations for the reactions described.

13) Sodium was burned in excess oxygen, the resulting crystalline substance was placed in a glass tube and carbon dioxide was passed through it. The gas coming out of the tube was collected and phosphorus was burned in its atmosphere. The resulting substance was neutralized with an excess of sodium hydroxide solution. Write the equations for the reactions described.

14) A solution of hydrochloric acid was added to the solution obtained by reacting sodium peroxide with water when heated until the reaction was completed. The solution of the resulting salt was subjected to electrolysis with inert electrodes. The gas formed as a result of electrolysis at the anode was passed through a suspension of calcium hydroxide. Write the equations for the reactions described.

15) Sulfur dioxide was passed through a solution of sodium hydroxide until a medium salt was formed. An aqueous solution of potassium permanganate was added to the resulting solution. The resulting precipitate was separated and treated with hydrochloric acid. The released gas was passed through a cold solution of potassium hydroxide. Write the equations for the reactions described.

16) A mixture of silicon (IV) oxide and magnesium metal was calcined. The simple substance obtained as a result of the reaction was treated with a concentrated solution of sodium hydroxide. The released gas was passed over heated sodium. The resulting substance was placed in water. Write the equations for the reactions described.

17) The product of the reaction of lithium with nitrogen was treated with water. The resulting gas was passed through a solution of sulfuric acid until the chemical reactions stopped. The resulting solution was treated with a barium chloride solution. The solution was filtered, and the filtrate was mixed with sodium nitrate solution and heated. Write the equations for the reactions described.

18) Sodium was heated in a hydrogen atmosphere. When water was added to the resulting substance, gas evolution and the formation of a clear solution were observed. Brown gas was passed through this solution, which was obtained as a result of the interaction of copper with a concentrated solution of nitric acid. Write the equations for the reactions described.

19) Sodium bicarbonate was calcined. The resulting salt was dissolved in water and mixed with an aluminum solution, resulting in the formation of a precipitate and the release of a colorless gas. The precipitate was treated with an excess of nitric acid solution, and the gas was passed through a solution of potassium silicate. Write the equations for the reactions described.

20) Sodium was fused with sulfur. The resulting compound was treated with hydrochloric acid, the released gas completely reacted with sulfur (IV) oxide. The resulting substance was treated with concentrated nitric acid. Write the equations for the reactions described.

21) Sodium is burned in excess oxygen. The resulting substance was treated with water. The resulting mixture was boiled, after which chlorine was added to the hot solution. Write the equations for the reactions described.

22) Potassium was heated in a nitrogen atmosphere. The resulting substance was treated with an excess of hydrochloric acid, after which a suspension of calcium hydroxide was added to the resulting mixture of salts and heated. The resulting gas was passed through hot copper (II) oxide. Write the equations for the reactions described.

23) Potassium was burned in an atmosphere of chlorine, the resulting salt was treated with an excess of an aqueous solution of silver nitrate. The precipitate that formed was filtered off, the filtrate was evaporated and carefully heated. The resulting salt was treated with an aqueous solution of bromine. Write the equations for the reactions described.

24) Lithium reacted with hydrogen. The reaction product was dissolved in water, which formed a gas that reacted with bromine, and the resulting solution, when heated, reacted with chlorine to form a mixture of two salts. Write the equations for the reactions described.

25) Sodium was burned in air. The resulting solid absorbs carbon dioxide, releasing oxygen and salt. The last salt was dissolved in hydrochloric acid, and a solution of silver nitrate was added to the resulting solution. A white precipitate formed. Write the equations for the reactions described.

26) Oxygen was exposed to an electric discharge in an ozonizer. The resulting gas was passed through an aqueous solution of potassium iodide, and a new gas, colorless and odorless, was released, supporting combustion and respiration. In the atmosphere of the latter gas, sodium was burned, and the resulting solid reacted with carbon dioxide. Write the equations for the reactions described.

I A group.

1. N 2 + O 2 2NO

2NO + O 2 = 2NO 2

2NO 2 + 2NaOH = NaNO 3 + NaNO 2 + H 2 O

2NaNO 3 2NaNO 2 + O 2

2. 2NaCl 2Na + Cl2

at the cathode at the anode

2Na + O 2 = Na 2 O 2

2Na 2 O 2 + 2CO 2 = 2Na 2 CO 3 + O 2

Na 2 CO 3 + 2NH 4 Cl = 2NaCl + CO 2 + 2NH 3 + H 2 O

3. NaHCO 3 + HNO 3 = NaNO 3 + CO 2 + H 2 O

2NaNO 3 2NaNO 2 + O 2

5NaNO 2 + 2KMnO 4 + 3H 2 SO 4 = 5NaNO 3 + 2MnSO 4 + K 2 SO 4 + 3H 2 O

NaNO 3 + 4Zn + 7NaOH + 6H 2 O = 4Na 2 + NH 3

4. 2H2O + 2NaI H 2 + 2NaOH + I 2

2K + I 2 = 2KI

8KI + 5H 2 SO 4 (conc.) = 4K 2 SO 4 + H 2 S + 4I 2 + 4H 2 O

3H 2 S + 2K 2 CrO 4 + 2H 2 O = 2Cr(OH) 3 ↓ + 3S↓ + 4KOH

5. 2NaCl 2Na + Cl2

at the cathode at the anode

2Na + O 2 = Na 2 O 2

Na 2 O 2 + SO 2 = Na 2 SO 4

Na 2 SO 4 + Ba(OH) 2 = BaSO 4 ↓ + 2NaOH

6. P 4 + 3KOH + 3H 2 O = 3KH 2 PO 2 + PH 3

2PH 3 + 4O 2 = P 2 O 5 + 3H 2 O

P 2 O 5 + 4NaOH = 2Na 2 HPO 4 + H 2 O

2Na 2 HPO 4 Na 4 P 2 O 7 + H 2 O

Department of Education of the Ardatovsky Administration municipal district Nizhny Novgorod region

Municipal educational institution

"Ardatovskaya secondary school No. 1"

Competition of research works and projects for children of preschool and primary school age “I am a researcher”

Nomination: Ecological and biological activities

"Where does the salt go?

if dissolved

her in the water?

Work completed:

Plotov Gleb Yurievich - 8 years old,

2nd grade student

Supervisor:

Makurina Marina Nikolaevna,

primary school teacher

p.g.t. Ardatov

2008

Explanatory note from the manager.

I have been a primary school teacher for over 20 years. And elementary school children are very inquisitive, they are interested in knowing everything. Why is the Earth round? Where do the rivers flow? Why is it snowing? Where does sugar go when it is thrown into a cup of hot tea? Why is lemon sour and banana sweet? The teacher needs to answer all these and other similar questions. What if children themselves find answers to their questions? I decided on a small experiment - I invited the most inquisitive student to conduct research on the question “Where does salt go if it is dissolved in water?” And so, go ahead, in search of salt!

Introduction…………………………………………………………………….4 p.

Research methodology and technology…………………………………..6 pp.

Results of the study and their discussion…………………………7 pages.

Conclusions……………………………………………………………...8 pages.

List of used literature………………………………...9 pages.

Appendix……………………………………………………… 10 pages.

1. Introduction.

I’m in second grade, I’ve learned a lot of necessary and interesting things, but there’s so much more I want to know! I love reading educational books and learn a lot of interesting things from them. And one day my mother asked me to salt the pasta water. I threw a small spoonful of salt into the bowl, then stirred it and saw that the salt had disappeared. Where did she go? This became interesting to me. The next day I asked my teacher about this, and she advised me to conduct the research myself, with her help, of course. But first I decided to find out everything about salt, what it is, where it comes from.

Purpose of my research

– find out where salt goes when you dissolve it in water.

Tasks:

-learn about what salt is and where it is mined

-conduct experiments on dissolving salt in water and evaporating salt from a saline solution.

-draw conclusions based on the results of my research

“Salt is a crystalline substance that dissolves well in water. There is a lot of it in the seas, where it comes from tributaries. In turn, river water absorbs it from the soil through which it flows.

Salt, or sodium chloride. - a substance extremely important for life. The human body also contains quite a lot of salt. It is also found in natural foods. But we love it so much that we always add it to our food. The salt we eat comes mostly from seawater. One liter of it contains 30-40 grams of salt.” . (“Everything about everything” Popular encyclopedia for children. volume 8. / G. Shalaeva 1994, pp. 280-281.)

“Salt is obtained from salt mines, springs, salt lakes and from the sea.

In salt mines, the tunnels and corridors sparkle as if they were made of ice. Miners cut out blocks, which are then broken into pieces, loaded into trolleys and transported upstairs on special trains. In some places, salt is extracted through special salt wells. Wells are usually drilled to extract water. On the contrary, they pour into salt wells hot water. The water spreads underground and dissolves the salt. A brine forms underground. Then the brine is pumped out and heated in huge tanks. There the water evaporates and the salt settles to the bottom.

Sometimes the underground river of rock salt deposits is crossed by underground rivers. Then the water dissolves the salt, and salt caves form underground.

The largest salt caves are located in the Czech Republic, near the village of Velichka.

Salt is also mined in another way. Special shallow pools - salt presses - are built on the seashore. By special channel they are filled with sea water.

The hot sun heats the water, and it quickly evaporates, and the salt it brings remains in the pool.

In ancient times, salt was brought to Europe from afar. It was mined mainly in coastal areas and on some salt lakes.

This is why salt was highly valued, along with precious metals. In some places, salt was even used as a money substitute.

There are two such lakes in Russia - Elton and Baskunchak. Salt has been mined on their shores since ancient times.

Salt plays a huge role in human life; it is not only consumed as food. Previously, it was the main substance for preserving food products from spoilage.” (“Everything about everything” Popular encyclopedia for children. volume 11. / G. Shalaeva 1999 pp. 277-278)

2. Research methodology and technology.

Experiment No. 1 Dissolving salt in water.

Take plain water from the tap and taste it. (photo 1)

Then the salt is tasted in the same way. (photo 2)

Then the water is tasted with salt mixed in it. (photo 5)

The brine solution is poured into an aluminum pan and placed on fire. (photo 6)

Monitoring the state of the solution. (photo 7)

Determine the taste of the resulting white coating - “flies”. (photo 8,9)

Examine table salt under a magnifying glass. (photo10)

Examine under a magnifying glass the white coating formed in the pan after the water evaporates. (photo 11)

3. Research results and discussion.

Experience No. 1. Dissolving salt in water.

Water has no taste.

Salt has a salty taste.

After stirring, no salt is visible in the water.

The water became salty.

Experience No. 2. Evaporation of salt from brine solution.

After boiling, the water gradually begins to evaporate, and then completely disappeared.

White “flies” appeared on the walls and bottom of the pan.

The “flies” taste salty.

Experience No. 3. Comparison of table salt and “flies”

Salt is represented by soda as transparent pebbles - crystals of various shapes and volumes.

“Flies” are white and much smaller than salt crystals, similar to powder.

4. Conclusions.

Conclusion 1. – If you mix salt in water, the water will become salty. But the salt itself is not visible in the water. From all this it follows that the salt dissolved in the water.

Conclusion 2 – When the moisture evaporates from the salt solution, the salt remains on the walls and at the bottom of the pan, turning into white powder - “flies”.

Conclusion 3 – Salt, dissolving in water, breaks down into small particles.

General conclusion - This means that salt does not disappear from the water. It’s just that salt crystals, when they get into the water, break up into such small particles that they are not visible. But at the same time, they exist, since after the water evaporates, a white coating remains, formed from these invisible particles, which has a salty taste. And we can say that particles of salt and particles of water are friends. They extend their hands to each other, connecting in a strong handshake - saline.

List of used literature.

Everything about everything. Popular encyclopedia for children. Volume 8. Compiled by: G. Shalaeva. Philological Society "Slovo" AST. Center for the Humanities at the Faculty of Journalism of Moscow State University. M.V.Lomonosov., M., 1994

Everything about everything. Popular encyclopedia for children. Volume 11. Compiled by: G. Shalaeva. Philological Society "Slovo" AST. Center for the Humanities at the Faculty of Journalism of Moscow State University. M.V.Lomonosova, M., 19 99

6. Application.

Photo 1.Take plain water from the tap and taste it

Photo 2. Then the salt is tasted in the same way.

Photo 5. Then the water is tasted with salt mixed in it.

Photo 6. The brine solution is poured into an aluminum pan and placed on fire.

Photo 7. Monitoring the state of the solution.

Photos 8 and 9. Determine the taste of the resulting white coating - “flies”.

Photo 10. Examine table salt under a magnifying glass.

Photo 11. Examine under a magnifying glass the white coating formed in the pan after the water evaporates.