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Any acid is a complex substance, the molecule of which contains one or more hydrogen atoms and an acid residue.

The formula of sulfuric acid is H2SO4. Therefore, the composition of the sulfuric acid molecule includes two hydrogen atoms and the acid residue SO4.

Sulfuric acid is formed when sulfur oxide reacts with water

SO3+H2O -> H2SO4

Pure 100% sulfuric acid (monohydrate) is a heavy liquid, viscous like oil, colorless and odorless, with a sour "copper" taste. Already at a temperature of +10 ° C, it solidifies and turns into a crystalline mass.

Concentrated sulfuric acid contains approximately 95% H2SO4. And it freezes at temperatures below -20 ° C.

Interaction with water

Sulfuric acid is highly soluble in water, mixing with it in any ratio. This releases a large amount of heat.

Sulfuric acid is able to absorb water vapor from the air. This property is used in industry for drying gases. Gases are dried by passing them through special containers with sulfuric acid. Of course, this method can only be used for those gases that do not react with it.

It is known that when sulfuric acid comes into contact with many organic substances, especially carbohydrates, these substances are charred. The fact is that carbohydrates, like water, contain both hydrogen and oxygen. Sulfuric acid robs them of these elements. What remains is coal.

In an aqueous solution of H2SO4, the indicators litmus and methyl orange turn red, which indicates that this solution has a sour taste.

Interaction with metals

Like any other acid, sulfuric acid is capable of replacing hydrogen atoms with metal atoms in its molecule. It interacts with almost all metals.

dilute sulfuric acid reacts with metals like a normal acid. As a result of the reaction, a salt with an acidic residue SO4 and hydrogen are formed.

Zn + H2SO4 = ZnSO4 + H2

BUT concentrated sulfuric acid is a very strong oxidizing agent. It oxidizes all metals, regardless of their position in the voltage series. And when reacting with metals, it itself is reduced to SO2. Hydrogen is not released.

Сu + 2 H2SO4 (conc) = CuSO4 + SO2 + 2H2O

Zn + 2 H2SO4 (conc) = ZnSO4 + SO2 + 2H2O

But gold, iron, aluminum, platinum group metals do not oxidize in sulfuric acid. Therefore, sulfuric acid is transported in steel tanks.

Sulfuric acid salts, which are obtained as a result of such reactions, are called sulfates. They are colorless and crystallize easily. Some of them are highly soluble in water. Only CaSO4 and PbSO4 are sparingly soluble. BaSO4 is almost insoluble in water.

Interaction with bases

The reaction of an acid with a base is called a neutralization reaction. As a result of the neutralization reaction of sulfuric acid, a salt containing the acid residue SO4 and water H2O is formed.

Examples of sulfuric acid neutralization reactions:

H2SO4 + 2 NaOH = Na2SO4 + 2 H2O

H2SO4 + CaOH = CaSO4 + 2 H2O

Sulfuric acid enters into a neutralization reaction with both soluble and insoluble bases.

Since there are two hydrogen atoms in the sulfuric acid molecule, and two bases are required to neutralize it, it belongs to dibasic acids.

Interaction with basic oxides

From the school chemistry course, we know that oxides are called complex substances, which include two chemical elements, one of which is oxygen in the oxidation state -2. Basic oxides are called oxides of 1, 2 and some 3 valence metals. Examples of basic oxides: Li2O, Na2O, CuO, Ag2O, MgO, CaO, FeO, NiO.

With basic oxides, sulfuric acid enters into a neutralization reaction. As a result of such a reaction, as in the reaction with bases, salt and water are formed. The salt contains the acid residue SO4.

CuO + H2SO4 = CuSO4 + H2O

Salt interaction

Sulfuric acid reacts with salts of weaker or volatile acids, displacing these acids from them. As a result of this reaction, a salt with an acidic residue SO4 and an acid

H2SO4+BaCl2=BaSO4+2HCl

The use of sulfuric acid and its compounds

Barium porridge BaSO4 is able to delay x-rays. Filling it with the hollow organs of the human body, radiologists examine them.

In medicine and construction, natural gypsum CaSO4 * 2H2O, calcium sulfate hydrate is widely used. Glauber's salt Na2SO4 * 10H2O is used in medicine and veterinary medicine, in the chemical industry - for the production of soda and glass. Copper sulfate CuSO4 * 5H2O is known to gardeners and agronomists who use it to control pests and plant diseases.

Sulfuric acid is widely used in various industries: chemical, metalworking, petroleum, textile, leather and others.

Acids are chemical compounds consisting of hydrogen atoms and acidic residues, for example, SO4, SO3, PO4, etc. They are inorganic and organic. The former include hydrochloric, phosphoric, sulfide, nitric, sulfuric acid. To the second - acetic, palmitic, formic, stearic, etc.

What is sulfuric acid

This acid consists of two hydrogen atoms and an acid residue SO4. It has the formula H2SO4.

Sulfuric acid, or, as it is also called, sulfate, refers to inorganic oxygen-containing dibasic acids. This substance is considered one of the most aggressive and chemically active. In most chemical reactions, it acts as an oxidizing agent. This acid can be used in concentrated or diluted form, in these two cases it has slightly different chemical properties.

Physical Properties

Sulfuric acid under normal conditions has a liquid state, its boiling point is approximately 279.6 degrees Celsius, the freezing point when it turns into solid crystals is about -10 degrees for one hundred percent and about -20 for 95 percent.

Pure 100% sulphate acid is an odorless and colorless oily liquid substance, which has almost twice the density of water - 1840 kg / m3.

Chemical properties of sulfate acid

Sulfuric acid reacts with metals, their oxides, hydroxides and salts. Diluted with water in various proportions, it can behave differently, so let's take a closer look at the properties of a concentrated and weak solution of sulfuric acid separately.

concentrated sulfuric acid solution

A concentrated solution is considered to be a solution that contains from 90 percent sulfate acid. Such a solution of sulfuric acid is able to react even with inactive metals, as well as with non-metals, hydroxides, oxides, salts. The properties of such a solution of sulfate acid are similar to those of concentrated nitrate acid.

Interaction with metals

During the chemical reaction of a concentrated solution of sulfate acid with metals located to the right of hydrogen in the electrochemical series of metal voltages (that is, with not the most active), the following substances are formed: sulfate of the metal with which the interaction takes place, water and sulfur dioxide. The metals, as a result of interaction with which the listed substances are formed, include copper (cuprum), mercury, bismuth, silver (argentum), platinum and gold (aurum).

Interaction with inactive metals

With metals that are to the left of hydrogen in the voltage series, concentrated sulfuric acid behaves a little differently. As a result of such a chemical reaction, the following substances are formed: sulfate of a certain metal, hydrogen sulfide or pure sulfur and water. The metals with which such a reaction takes place also include iron (ferum), magnesium, manganese, beryllium, lithium, barium, calcium and all the others that are in the series of voltages to the left of hydrogen, except for aluminum, chromium, nickel and titanium - with them concentrated sulfate acid does not react.

Interaction with non-metals

This substance is a strong oxidizing agent, therefore it is able to participate in redox chemical reactions with non-metals, such as, for example, carbon (carbon) and sulfur. As a result of such reactions, water is necessarily released. When this substance is added to carbon, carbon dioxide and sulfur dioxide are also released. And if you add acid to sulfur, you get only sulfur dioxide and water. In such a chemical reaction, sulfate acid plays the role of an oxidizing agent.

Interaction with organic substances

Carbonization can be distinguished among the reactions of sulfuric acid with organic substances. Such a process occurs when a given substance collides with paper, sugar, fibers, wood, etc. In this case, carbon is released in any case. The carbon formed during the reaction can partially interact with sulfuric acid in excess. The photo shows the reaction of sugar with a solution of sulfate acid of medium concentration.

Reactions with salts

Also, a concentrated solution of H2SO4 reacts with dry salts. In this case, a standard exchange reaction occurs, in which metal sulfate is formed, which was present in the structure of the salt, and an acid with a residue that was in the composition of the salt. However, concentrated sulfuric acid does not react with salt solutions.

Interaction with other substances

Also, this substance can react with metal oxides and their hydroxides, in these cases exchange reactions occur, in the first metal sulfate and water are released, in the second - the same.

Chemical properties of a weak solution of sulfate acid

Dilute sulfuric acid reacts with many substances and has the same properties as all acids. It, unlike concentrated, interacts only with active metals, that is, those that are to the left of hydrogen in a series of voltages. In this case, the same substitution reaction occurs, as in the case of any acid. This releases hydrogen. Also, such an acid solution interacts with salt solutions, as a result of which an exchange reaction occurs, already discussed above, with oxides - just like concentrated, with hydroxides - also the same. In addition to ordinary sulfates, there are also hydrosulfates, which are the product of the interaction of hydroxide and sulfuric acid.

How to know if a solution contains sulfuric acid or sulfates

To determine whether these substances are present in a solution, a special qualitative reaction for sulfate ions is used, which allows you to find out. It consists in adding barium or its compounds to the solution. As a result, a white precipitate (barium sulfate) may form, indicating the presence of sulfates or sulfuric acid.

How is sulfuric acid produced?

The most common method of industrial production of this substance is its extraction from iron pyrite. This process occurs in three stages, each of which occurs a certain chemical reaction. Let's consider them. First, oxygen is added to pyrite, resulting in the formation of ferum oxide and sulfur dioxide, which is used for further reactions. This interaction occurs at high temperature. This is followed by a step in which, by adding oxygen in the presence of a catalyst, which is vanadium oxide, sulfur trioxide is obtained. Now, at the last stage, water is added to the resulting substance, and sulfate acid is obtained. This is the most common process for the industrial extraction of sulfate acid, it is used most often because pyrite is the most accessible raw material suitable for the synthesis of the substance described in this article. Sulfuric acid obtained using such a process is used in various industries - both in the chemical industry and in many others, for example, in oil refining, ore dressing, etc. It is also often used in the manufacturing technology of many synthetic fibers .

Target: To get acquainted with the structure, physical and chemical properties, the use of sulfuric acid.

Educational tasks: Consider the physical and chemical properties (common with other acids and specific) of sulfuric acid, obtaining, show the great importance of sulfuric acid and its salts in the national economy.

Educational tasks: To continue the formation of a dialectical-materialistic understanding of nature among students.

Development tasks: Development of general educational skills and abilities, work with a textbook and additional literature, rules for working on a desktop, the ability to systematize and generalize, establish cause-and-effect relationships, express one’s thoughts conclusively and competently, draw conclusions, draw diagrams, sketch.

During the classes

1. Repetition of the past.

Frontal class survey. Compare the properties of crystalline and plastic sulfur. Explain the essence of allotropy.

2. Learning new material.

After carefully listening to the tale, we will explain at the end of the lesson why sulfuric acid behaved strangely with water, wood and a golden ring.

Sounds like an audio recording.

The Adventures of Sulfuric Acid.

In one chemical kingdom lived a sorceress, her name was sulfuric acid. It didn't look so bad, it was a colorless liquid, viscous like oil, odorless. Sulphuric acid I wanted to be famous, so I went on a trip.

She had already been walking for 5 hours, and since the day was too hot, she was very thirsty. And suddenly she saw a well. "Water!" acid exclaimed, and running to the well, she touched the water. The water hissed terribly. With a cry, the frightened sorceress rushed away. Of course, the young acid did not know that when mixed sulfuric acid water releases a large amount of heat.

"If water comes into contact with sulfuric acid, then the water, not having time to mix with the acid, can boil and throw out splashes sulfuric acid. This entry appeared in the diary of a young traveler, and then entered the textbooks.

Since the acid did not quench their thirst, then, a sprawling tree, decided to lie down and rest in the shade. But she didn't succeed either. Once Sulphuric acid touched the tree, it began to char. Not knowing the reason for this, the frightened acid ran away.

Soon she came to the city and decided to go to the first store that came across her way. They turned out to be jewelry. Approaching the shop windows, the acid saw many beautiful rings. Sulphuric acid I decided to try one ring. Asking the seller for a gold ring, the traveler put it on her long beautiful finger. The sorceress really liked the ring and she decided to buy it. That's what she could boast to her friends!

Leaving the city, the acid went home. On the way, the thought did not leave her, why did water and wood behave so strangely when touched with her, but nothing happened to this golden thing? “Yes, because gold is in sulfuric acid does not oxidize. These were the last words written by acid in his diary.

Teacher's explanation.

Electronic and structural formulas of sulfuric acid.

Since sulfur is in the 3rd period of the periodic system, the octet rule (eight electronic structure) is not respected and a sulfur atom can acquire up to twelve electrons. The electronic and structural formulas of sulfuric acid are as follows:

(The six electrons of sulfur are marked with an asterisk)

Receipt.

Sulfuric acid is formed by the interaction of sulfur oxide (5) with water (SO 3 + H 2 O -> H 2 SO 4).

physical properties.

Sulfuric acid is a colorless, heavy, non-volatile liquid. When dissolved in water, a very strong heating occurs. remember, that do not pour water into concentrated sulfuric acid!

Concentrated sulfuric acid absorbs water vapor from the air. This can be seen if an open vessel with concentrated sulfuric acid is balanced on a scale: after a while, the cup with the vessel will sink.

Chemical properties.

Dilute sulfuric acid has properties common to all acids. In addition, sulfuric acid has specific properties.

Chemical properties of sulfuric - Application .

Demonstration by the teacher of an entertaining experience.

Brief safety briefing.

Eskimo (Charcoal from sugar)

Students fill out a table with an entertaining experience in a notebook.

Students' reasoning about why Sulfuric acid behaved so strangely with water, wood and gold.

Application.

Due to its properties (the ability to absorb water, oxidizing properties, non-volatility), sulfuric acid is widely used in the national economy. It belongs to the main products of the chemical industry.

1. receiving dyes;
2. obtaining mineral fertilizers;
3. cleaning of oil products;
4. electrolytic production of copper;
5. electrolyte in batteries;
6. receiving explosives;
7. receiving dyes;
8. obtaining artificial silk;
9. receiving glucose;
10. obtaining salts;
11. obtaining acids.

Salts of sulfuric acid are widely used, for example

Na 2 SO 4 * 10H 2 O– sodium sulfate crystalline hydrate (Glauber's salt)- used in the production of soda, glass, in medicine and veterinary medicine.

CaSO4*2H2O- hydrated calcium sulfate (natural gypsum)- used to obtain semi-aqueous gypsum, which is necessary in construction, and in medicine - for applying plaster bandages.

CuSO4*5H2O– hydrated copper sulfate (2) (copper sulfate)- used in the fight against pests and plant diseases.

The work of students with the extra-textual component of the textbook.

It is interesting

…in the Gulf of Kara-Bogaz-Gol, the water contains 30% of Glauber's salt at a temperature of +5 ° C, this salt precipitates as a white precipitate, like snow, and with the onset of warm weather, the salt dissolves again. Since Glauber's salt appears and disappears in this bay, it was named mirabilite, which means "wonderful salt".

3. Questions to consolidate the educational material, written on the board.

1. In winter, a vessel with concentrated sulfuric acid is sometimes placed between the window frames. What is the purpose of doing this, why can't the vessel be filled with acid to the top?
2. Why is sulfuric acid called the "bread" of chemistry?

Homework and instructions for its implementation.

Where appropriate, write equations in ionic form.

Conclusion on the lesson, setting and commenting marks.

References.

1. Rudzitis G.E. Feldman F.G., Chemistry: A textbook for grades 7-11 of an evening (shift) secondary school at 2 hours. Part 1-3 edition - M .: Education, 1987.
2. Chemistry at school No. 6, 1991.
3. Strempler Genrikh Ivanovich, Chemistry at leisure: Book. for students Wednesdays. and old. age /Fig. ed. with the participation of V.N. Rastopchiny.- F .: Ch. ed. KSE, 1990.

Undiluted sulfuric acid is a covalent compound.

In a molecule, sulfuric acid is tetrahedrally surrounded by four oxygen atoms, two of which are part of the hydroxyl groups. The S–O bonds are double, and the S–OH bonds are single.

Colorless, ice-like crystals have a layered structure: each H 2 SO 4 molecule is connected to four neighboring strong hydrogen bonds, forming a single spatial framework.

The structure of liquid sulfuric acid is similar to the structure of solid one, only the integrity of the spatial frame is broken.

Physical properties of sulfuric acid

Under normal conditions, sulfuric acid is a heavy oily liquid, colorless and odorless. In engineering, sulfuric acid is called its mixtures with both water and sulfuric anhydride. If the molar ratio of SO 3: H 2 O is less than 1, then this is an aqueous solution of sulfuric acid, if more than 1, it is a solution of SO 3 in sulfuric acid.

100% H 2 SO 4 crystallizes at 10.45 °C; T bp = 296.2 °C; density 1.98 g/cm 3 . H 2 SO 4 mixes with H 2 O and SO 3 in any ratio to form hydrates, the heat of hydration is so great that the mixture can boil, splatter and cause burns. Therefore, it is necessary to add acid to water, and not vice versa, since when water is added to acid, lighter water will be on the surface of the acid, where all the heat released will be concentrated.

When aqueous solutions of sulfuric acid containing up to 70% H 2 SO 4 are heated and boiled, only water vapor is released into the vapor phase. Sulfuric acid vapors also appear above more concentrated solutions.

In terms of structural features and anomalies, liquid sulfuric acid is similar to water. Here is the same system of hydrogen bonds, almost the same spatial framework.

Chemical properties of sulfuric acid

Sulfuric acid is one of the strongest mineral acids; due to its high polarity, the H-O bond is easily broken.

Sulfuric acid dissociates in aqueous solution , forming a hydrogen ion and an acid residue:

H 2 SO 4 \u003d H + + HSO 4 -;

HSO 4 - \u003d H + + SO 4 2-.

Summary Equation:

H 2 SO 4 \u003d 2H + + SO 4 2-.

Shows the properties of acids , reacts with metals, metal oxides, bases and salts.

Dilute sulfuric acid does not exhibit oxidizing properties; when it interacts with metals, hydrogen and a salt containing the metal in the lowest oxidation state are released. In the cold, acid is inert to metals such as iron, aluminum, and even barium.

The concentrated acid has oxidizing properties. Possible products of interaction of simple substances with concentrated sulfuric acid are given in the table. The dependence of the reduction product on the concentration of the acid and the degree of activity of the metal is shown: the more active the metal, the deeper it reduces the sulfate ion of sulfuric acid.

Interaction with oxides:

CaO + H 2 SO 4 \u003d CaSO 4 \u003d H 2 O.

Interaction with bases:

2NaOH + H 2 SO 4 \u003d Na 2 SO 4 + 2H 2 O.

Interaction with salts:

Na 2 CO 3 + H 2 SO 4 = Na 2 SO 4 + CO 2 + H 2 O.

Oxidizing properties

Sulfuric acid oxidizes HI and HBr to free halogens:

H 2 SO 4 + 2HI \u003d I 2 + 2H 2 O + SO 2.

Sulfuric acid removes chemically bound water from organic compounds containing hydroxyl groups. Dehydration of ethyl alcohol in the presence of concentrated sulfuric acid leads to the production of ethylene:

C 2 H 5 OH \u003d C 2 H 4 + H 2 O.

Charring of sugar, cellulose, starch and other carbohydrates upon contact with sulfuric acid is also explained by their dehydration:

C 6 H 12 O 6 + 12H 2 SO 4 \u003d 18H 2 O + 12SO 2 + 6CO 2.

New Topic: Sulfuric Acid -H 2 SO 4

1. Electronic and structural formulas of sulfuric acid

*S - sulfur is in an excited state 1S 2 2S 2 2P 6 3S 1 3P 3 3d 2

The electronic formula of the sulfuric acid molecule:

Structural formula of the sulfuric acid molecule:

1 H - -2 O -2 O

1 H - -2 O -2 O

2. Receipt:

The chemical processes for the production of sulfuric acid can be represented as the following scheme:

S + O 2 + O 2 + H 2 O

FeS 2 SO 2 SO 3 H 2 SO 4

Sulfuric acid is produced in three stages:

1 stage. Sulfur, iron pyrite or hydrogen sulfide are used as raw materials.

4 FeS 2 + 11 O 2 \u003d 2Fe 2 O 3 + 8SO 2

2 stage. Oxidation of SO 2 to SO 3 with oxygen using a catalyst V 2 O 5

2SO 2 + O 2 \u003d 2SO 3 + Q

3rd stage. Not water is used to convert SO 3 to sulfuric acid. there is a strong heating, and a concentrated solution of sulfuric acid.

SO 3 + H 2 O H 2 SO 4

The result is oleum - a solutionSO 3 in sulfuric acid.

Apparatus circuit diagram(see textbook p.105)

3.Physical properties.

a) liquid b) colorless c) heavy (vitriol) d) non-volatile

d) when dissolved in water, strong heating occurs ( so sulfuric acid must be poured intowater,anot vice versa!)

4. Chemical properties of Sulfuric acid.

5.Application: Sulfuric acid is one of the most important products used in various industries. Its main consumers are the production of mineral fertilizers, metallurgy, and refining of petroleum products. Sulfuric acid is used in the manufacture of other acids, detergents, explosives, medicines, paints, and as electrolytes for lead-acid batteries. (Textbook p.103).

6.Salts of sulfuric acid

Sulfuric acid dissociates in steps

H 2 SO 4 H + + HSO 4 -

HSO 4 - H + + SO 4 2-

therefore, it forms two types of salts - sulfates and hydrosulfates

For example: Na 2 SO 4 - sodium sulfate (medium salt)

Na HSO 4 - sodium hydrogen sulfate (acid salt)

The most widely used are:

Na 2 SO 4 * 10H 2 O - Glauber's salt (used in the production of soda, glass, in medicine and

veterinary medicine.

CaSO 4 * 2H 2 O - gypsum

CuSO 4 * 5H 2 O - copper sulfate (used in agriculture).

Laboratory experience

Chemical properties of sulfuric acid.

Equipment: Test tubes.

Reagents: sulfuric acid, methyl orange, zinc, magnesium oxide, sodium hydroxide and phenolphthalein, sodium carbonate, barium chloride.

b) Fill in the table of observations

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