Feo basic oxide. Iron and its compounds
DEFINITION
Iron(II) oxide under normal conditions, it is a black powder (Fig. 1), decomposing upon moderate heating and re-forming from the decomposition products upon further heating.
After calcination, it is chemically inactive. Pyrophorene powder. Does not react with cold water. Shows amphoteric properties (with a predominance of basic). Easily oxidized by oxygen. It is reduced by hydrogen and carbon.
Rice. 1. Iron oxide (II). Appearance.
Chemical formula of iron oxide 2
The chemical formula of iron(II) oxide is FeO. The chemical formula shows the qualitative and quantitative composition of the molecule (how many and which atoms are present in it). According to the chemical formula, you can calculate the molecular weight of a substance (Ar (Fe) \u003d 56 amu, Ar (O) \u003d 16 amu):
Mr(FeO) = Ar(Fe) + Ar(O);
Mr(FeO) = 56 + 16 = 72.
Structural (graphical) formula of iron oxide 2
The structural (graphic) formula of a substance is more visual. It shows how atoms are connected to each other within a molecule. Below is the graphic formula of iron oxide (II):
Examples of problem solving
EXAMPLE 1
| Exercise | When neutralizing 25.5 g of saturated monobasic acid with an excess of sodium bicarbonate solution, 5.6 l (N.O.) of gas was released. Determine the molecular formula of the acid. |
| Solution | We write the equation for the neutralization reaction of a saturated monobasic acid with an excess of sodium bicarbonate solution in general form: C n H 2n+1 COOH + NaHCO 3 → C n H 2n+1 COONa + CO 2 + H 2 O. Calculate the amount of carbon dioxide released during the reaction: n(CO 2) \u003d V (CO 2) / V m; n(CO 2) \u003d 5.6 / 22.4 \u003d 0.25 mol. According to the reaction equation n(CO 2): n(C n H 2n+1 COOH) = 1:1, i.e. n (C n H 2n + 1 COOH) \u003d n (CO 2) \u003d 0.25 mol. Calculate the molar mass of the limiting monobasic acid: M(C n H 2n+1 COOH) = m(C n H 2n+1 COOH) / n(C n H 2n+1 COOH); M(C n H 2 n +1 COOH) \u003d 25.5 / 0.25 \u003d 102 g / mol. Let's determine the number of carbon atoms in the molecule of the limiting monobasic acid (the values of relative atomic masses taken from the Periodic Table of D.I. Mendeleev are rounded up to integers: 12 for carbon, 1 for hydrogen and 16 for oxygen): M(C n H 2n+1 COOH) = 12n + 2n + 1 + 12 + 16 + 16 +1 = 14n + 46; 14n + 46 = 102 g/mol; So the molecular formula of the limiting monobasic acid is C 4 H 9 COOH. |
| Answer | C4H9COOH |
EXAMPLE 2
| Exercise | Set the molecular formula of an alkene if it is known that 2.8 g of it can add 1120 ml (N.O.) of hydrogen chloride. |
| Solution | Let us write the equation for the reaction of the addition of hydrogen chloride to an alkene in general form: C n H 2 n + HCl → C n H 2 n +1 Cl. Calculate the amount of hydrogen chloride substance: n(HCl) = V(HCl) / V m ; n(HCl) = 1.2 / 22.4 = 0.05 mol. According to the reaction equation n(HCl): n(C n H 2n) = 1:1, i.e. n (C n H 2n) \u003d n (HCl) \u003d 0.05 mol. Calculate the molar mass of an alkene: M(C n H 2n) = m(C n H 2n) / n(C n H 2n); M(C n H 2 n) \u003d 2.8 / 0.05 \u003d 56 g / mol. Let's determine the number of carbon atoms in an alkene molecule (the values of relative atomic masses taken from the Periodic Table of D.I. Mendeleev are rounded up to integers: 12 for carbon and 1 for hydrogen): M(C n H 2 n) = 12n + 2n = 14n; 14n= 56 g/mol; So the molecular formula of the alkene is C 4 H 8. |
| Answer | C 4 H 8 |
Iron forms two oxides, in which it exhibits valencies II and III and oxidation states (+2) and (+3), respectively.
DEFINITION
Iron(II) oxide under normal conditions, it is a black powder (Fig. 1), decomposing upon moderate heating and re-forming from the decomposition products upon further heating.
After calcination, it is chemically inactive. Pyrophorene powder. Does not react with cold water. Shows amphoteric properties (with a predominance of basic). Easily oxidized by oxygen. It is reduced by hydrogen and carbon.
Rice. 1. Iron oxide (II). Appearance.
DEFINITION
It is a red-brown solid in the case of a trigonal modification or dark brown in the case of a cubic modification, which is the most reactive (Fig. 1).
Thermally stable. Melting point 1562 o C.
Rice. 1. Iron oxide (III).
Does not react with water, ammonia hydrate. Shows amphoteric properties, reacts with acids, alkalis. It is reduced by hydrogen, carbon monoxide, iron.
Chemical formula of iron oxide
The chemical formula of iron oxide (II) is FeO, and iron oxide (III) is Fe 2 O 3. The chemical formula shows the qualitative and quantitative composition of the molecule (how many and which atoms are present in it). According to the chemical formula, you can calculate the molecular weight of a substance (Ar (Fe) \u003d 56 amu, Ar (O) \u003d 16 amu):
Mr(FeO) = Ar(Fe) + Ar(O);
Mr(FeO) = 56 + 16 = 72.
Mr(Fe 2 O 3) = 2×Ar(Fe) + 3×Ar(O);
Mr(Fe 2 O 3) \u003d 2 × 56 + 3 × 16 \u003d 58 + 48 \u003d 160.
Structural (graphic) formula of iron oxide
The structural (graphic) formula of a substance is more visual. It shows how atoms are connected to each other within a molecule. Below are the graphic formulas of iron oxides (a - FeO, b - Fe 2 O 3):
Examples of problem solving
EXAMPLE 1
| Exercise | After analyzing the substance, it was found that it contains: sodium with a mass fraction of 0.4207 (or 42.07%), phosphorus with a mass fraction of 0.189 (or 18.91%), oxygen with a mass fraction of 0.3902 (or 39 .02%). Find the compound formula. |
| Solution | Let us denote the number of sodium atoms in the molecule as "x", the number of phosphorus atoms as "y", and the number of oxygen atoms as "z". Let us find the corresponding relative atomic masses of the elements sodium, phosphorus and oxygen (the values of the relative atomic masses taken from the Periodic Table of D.I. Mendeleev will be rounded up to whole numbers). Ar(Na) = 23; Ar(P) = 31; Ar(O) = 16. We divide the percentage of elements by the corresponding relative atomic masses. Thus, we will find the relationship between the number of atoms in the molecule of the compound: Na:P:O = 42.07/39: 18.91/31: 39.02/16; Na:P:O = 1.829: 0.61: 2.43. Let's take the smallest number as one (i.e. divide all numbers by the smallest number 0.61): 1,829/0,61: 0,61/0,61: 2,43/0,61; Therefore, the simplest formula for a compound of sodium, phosphorus and oxygen is Na 3 PO 4. It's sodium phosphate. |
| Answer | Na3PO4 |
EXAMPLE 2
| Exercise | The molar mass of a nitrogen compound with hydrogen is 32 g/mol. Determine the molecular formula of a substance in which the mass fraction of nitrogen is 85.7%. |
| Solution | The mass fraction of the element X in the molecule of the HX composition is calculated by the following formula: ω (X) = n × Ar (X) / M (HX) × 100%. Calculate the mass fraction of hydrogen in the compound: ω (H) \u003d 100% - ω (N) \u003d 100% - 85.7% \u003d 14.3%. Let us denote the number of moles of elements that make up the compound as "x" (nitrogen), "y" (hydrogen). Then, the molar ratio will look like this (the values of relative atomic masses taken from the Periodic Table of D.I. Mendeleev will be rounded to integers): x:y = ω(N)/Ar(N) : ω(H)/Ar(H); x:y= 85.7/14: 14.3/1; x:y= 6.12: 14.3= 1: 2. This means that the simplest formula for the combination of nitrogen with hydrogen will have the form NH 2 and a molar mass of 16 g / mol. To find the true formula of an organic compound, we find the ratio of the obtained molar masses: M substance / M (NH 2) \u003d 32 / 16 \u003d 2. This means that the indices of nitrogen and hydrogen atoms should be 2 times higher, i.e. the formula of the substance will look like N 2 H 4. This is hydrazine. |
| Answer | N 2 H 4 |
68. Iron compounds
Iron(II) oxide FeO- a black crystalline substance, insoluble in water and alkalis. FeO matches base Fe(OH)2.
Receipt. Iron oxide (II) can be obtained by incomplete reduction of magnetic iron ore with carbon monoxide (II):
Chemical properties. It is the main oxide. Reacts with acids to form salts:
Iron(II) hydroxide Fe(OH)2- white crystalline substance.
Receipt. Iron (II) hydroxide is obtained from ferrous salts by the action of alkali solutions:
Chemical properties. basic hydroxide. Reacts with acids:
In air, Fe (OH) 2 is oxidized to Fe (OH) 3:
Iron(III) oxide Fe2O3- a brown substance, occurs in nature in the form of red iron ore, insoluble in water.
Receipt. When firing pyrite:
Chemical properties. Shows weak amphoteric properties. When interacting with alkalis, it forms salts:
Iron(III) hydroxide Fe(OH)3- a substance of red-brown color, insoluble in water and excess alkali.
Receipt. Obtained by oxidation of iron oxide (III) and iron hydroxide (II).
Chemical properties. It is an amphoteric compound (with a predominance of basic properties). It precipitates under the action of alkalis on ferric salts:
Ferrous salts obtained by the interaction of metallic iron with the corresponding acids. They are strongly hydrolyzed, therefore their aqueous solutions are energetic reducing agents:
When heated above 480 °C, it decomposes, forming oxides:
Under the action of alkalis on iron (II) sulfate, iron (II) hydroxide is formed:
Forms a crystalline hydrate FeSO4?7H2O (iron vitriol). Iron (III) chloride FeCl3 – dark brown crystalline substance.
Chemical properties. Soluble in water. FeCl3 exhibits oxidizing properties.
Reducing agents - magnesium, zinc, hydrogen sulfide, are oxidized without heating.
FeO(l): 251 kJ/mol
Iron(II) oxide (iron oxide) is a complex inorganic compound of ferrous iron and oxygen.
Physical Properties
Black connection. Crystal lattice similar to rock salt. It has a non-stoichiometric structure with a homogeneity range from Fe 0.84 O to Fe 0.95 O. This is due to the fact that its crystal lattice is stable only when not all of its nodes are occupied by iron atoms. Stable iron oxide (II) becomes only with increasing temperature.
Being in nature
Iron(II) oxide occurs naturally as the mineral wüstite.
Receipt
- Heating iron at low oxygen partial pressure:
- Decomposition of iron (II) oxalate in vacuum:
- Interaction of iron with iron oxide (III) or iron oxide (II,III):
- Recovery of iron(III) oxide with carbon monoxide:
- Thermal decomposition of iron oxide (II, III):
- Thermal decomposition of iron (II) hydroxide without air access:
- Thermal decomposition of iron (II) carbonate without air access:
Chemical properties
- Interaction with dilute hydrochloric acid:
- Interaction with concentrated nitric acid:
- Fusion with sodium hydroxide:
- Interaction with oxygen:
- Interaction with hydrogen sulfide:
- Recovery with hydrogen and coke:
Application
- Participates in the blast-furnace process of iron smelting.
- It is used as a component of ceramics and mineral paints.
- In the food industry, it is widely used as a food coloring under the number E172.
The formation of a strong thin layer of iron(II) oxide on the surface of steel is the result of a process called bluing (blackening). By adjusting the thickness of this layer, in addition to black, any tint colors can be achieved. On this property of iron(II) oxide, the technology for obtaining color patterns on steel is built.
Toxicity
Aerosols (dust, smoke) of iron oxide (II) with prolonged exposure are deposited in the lungs and cause siderosis - a type of pneumoconiosis with a relatively benign course.
see also
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Literature
- Lidin R. A. “Handbook of a student. Chemistry "M.: Asterel, 2003.
- Volkov A.I., Zharsky I.M. Big chemical reference book / A.I. Volkov, I.M. Zharsky. - Minsk: Modern school, 2005. - 608 p.
- Lidin R.A. and other Chemical properties of inorganic substances: Proc. allowance for universities. 3rd ed., Rev./R.A. Lidin, V.A. Molochko, L.L. Andreeva; Ed. R.A. Lidina. - M.: Chemistry, 200. 480 p.: ill.
- Greenwood N. Chemistry of elements: in 2 volumes.
- .Greenwood, A. Earnshaw; per. from English. - M.: BINOM. Knowledge Laboratory, 2011. - (The best foreign textbook)
- Harmful chemicals. Inorganic compounds of groups V-VIII: Ref. ed./ A.L. Bandman, N.V. Volkova, T.D. Grekhova and others; Ed. V.A. Filova and others - L.: Chemistry, 1989. 592 p.
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An excerpt characterizing Iron(II) oxide
Natasha blushed purple upon hearing these words.- How blushing, how blushing, ma delicieuse! [my charm!] - Helen said. - You should definitely come. Si vous aimez quelqu "un, ma delicieuse, ce n" est pas une raison pour se cloitrer. Si meme vous etes promise, je suis sure que votre promis aurait desire que vous alliez dans le monde en son absence plutot que deperir d "ennui. [From the fact that you love someone, my lovely, you should not live as a nun. Even if you're a bride, I'm sure your fiancé would rather have you go out into the world in his absence than die of boredom.]
“So she knows that I am a bride, so she and her husband, with Pierre, with this fair Pierre, Natasha thought, talked and laughed about it. So it was nothing." And again, under the influence of Helen, what had previously seemed terrible seemed simple and natural. “And she is such a grande dame, [important lady,] so sweet and so evidently loves me with all her heart,” thought Natasha. And why not have fun? thought Natasha, looking at Helen with surprised, wide-open eyes.
Marya Dmitrievna returned to dinner, silent and serious, obviously having suffered a defeat at the old prince's. She was still too excited about the collision to be able to calmly tell the story. To the question of the count, she answered that everything was fine and that she would tell tomorrow. Learning about the visit of Countess Bezukhova and the invitation to the evening, Marya Dmitrievna said:
- I don’t like to hang out with Bezukhova and I won’t advise; Well, yes, if you promised, go, you’ll be scattered, ”she added, turning to Natasha.
Count Ilya Andreich took his girls to Countess Bezukhova. There were quite a lot of people at the evening. But the whole society was almost unfamiliar to Natasha. Count Ilya Andreich noted with displeasure that this whole society consisted mainly of men and women, known for their liberties of treatment. M lle Georges, surrounded by young people, stood in the corner of the living room. There were several Frenchmen, among them Metivier, who, since Helene's arrival, had been her housewife. Count Ilya Andreich made up his mind not to sit down at cards, not to leave his daughters, and to leave as soon as the performance of Georges was over.
Anatole was apparently at the door waiting for the Rostovs to enter. He immediately greeted the count, went up to Natasha and followed her. As soon as Natasha saw him, just as in the theater, a feeling of conceited pleasure that he liked her and fear from the absence of moral barriers between her and him seized her. Helen joyfully received Natasha and loudly admired her beauty and toilet. Shortly after their arrival, m lle Georges left the room to dress. In the living room they began to arrange chairs and sit down. Anatole moved a chair to Natasha and wanted to sit beside her, but the count, who did not take his eyes off Natasha, sat down beside her. Anatole sat in the back.
M lle Georges, with bare, dimpled, thick arms, in a red shawl worn over one shoulder, stepped into the empty space left for her between the chairs and stopped in an unnatural pose. An enthusiastic whisper was heard. M lle Georges looked sternly and gloomily at the audience and began to speak some verses in French, where it was about her criminal love for her son. In places she raised her voice, in places she whispered, solemnly raising her head, in places she stopped and wheezed, rolling her eyes.
- Adorable, divin, delicieux! [Amazing, divine, wonderful!] - was heard from all sides. Natasha looked at fat Georges, but heard nothing, saw nothing, and understood nothing of what was going on in front of her; she only felt completely irrevocable again in that strange, insane world, so far from the former, in that world in which it was impossible to know what was good, what was bad, what was rational and what was insane. Behind her sat Anatole, and she, feeling his closeness, fearfully waited for something.
After the first monologue, the whole society stood up and surrounded m lle Georges, expressing their delight to her.
- How good she is! Natasha said to her father, who, along with the others, got up and moved towards the actress through the crowd.
“I can’t find it, looking at you,” Anatole said, following Natasha. He said it at a time when she alone could hear him. - You are charming ... from the moment I saw you, I did not stop ....
“Let’s go, let’s go, Natasha,” said the count, returning for his daughter. - How good!
Natasha, without saying anything, went up to her father and looked at him with questioning surprised eyes.
After several receptions of recitation, m lle Georges left and the Countess Bezuhaya asked for company in the hall.
The count wanted to leave, but Helen begged not to spoil her impromptu ball. The Rostovs remained. Anatole invited Natasha to a waltz, and during the waltz, he, shaking her body and hand, told her that she was ravissante [charming] and that he loved her. During the ecossaise, which she again danced with Kuragin, when they were alone, Anatole did not say anything to her and only looked at her. Natasha was in doubt if she saw in a dream what he said to her during the waltz. At the end of the first figure, he again shook hands with her. Natasha looked up at him with frightened eyes, but such a self-confidently gentle expression was in his affectionate look and smile that she could not, looking at him, say what she had to tell him. She lowered her eyes.
“Don't tell me such things, I'm engaged and in love with another,” she said quickly ... - She looked at him. Anatole was not embarrassed or upset by what she said.
- Don't tell me about it. What is my business? - he said. “I'm saying I'm madly, madly in love with you. Is it my fault that you are amazing? We start.
Natasha, animated and anxious, looked around her with wide, frightened eyes and seemed more cheerful than usual. She hardly remembered anything from what had happened that evening. Ecossaise and Gros Vater danced, her father invited her to leave, she asked to stay. Wherever she was, whoever she spoke to, she could feel his eyes on her. Then she remembered that she had asked her father's permission to go into the dressing room to straighten her dress, that Helen had gone out to fetch her, told her laughing about her brother's love, and that she had met Anatole again in the little sofa room, that Helen had disappeared somewhere, they were left alone and Anatole, Taking her by the hand, he said in a gentle voice:
“I can’t visit you, but will I never see you again?” I love you madly. Really never? ... - and he, blocking her way, brought his face closer to her face.
His brilliant, large, masculine eyes were so close to hers that she could see nothing but those eyes.
- Natalie? his voice whispered inquiringly, and someone squeezed her hands painfully.
- Natalie?
"I don't understand anything, I have nothing to say," her look said.
Hot lips pressed against hers, and at that very moment she felt free again, and the sound of steps and Helen's dress was heard in the room. Natasha looked back at Helen, then, red and trembling, looked at him in frightened questioning and went to the door.
- Un mot, un seul, au nom de Dieu, [One word, only one, for God's sake,] - said Anatole.
She stopped. She so needed him to say that word, which would explain to her what had happened and to which she would answer him.
“Nathalie, un mot, un seul,” he repeated everything, apparently not knowing what to say, and repeated it until Helen approached them.
Helen went out into the living room again with Natasha. Not staying for supper, the Rostovs left.
Returning home, Natasha did not sleep all night: she was tormented by the insoluble question of whom she loved, Anatole or Prince Andrei. She loved Prince Andrei—she remembered clearly how much she loved him. But she loved Anatole too, that was beyond doubt. “Otherwise, how could all this be?” she thought. “If after that I could, after saying goodbye to him, answer his smile with a smile, if I could allow it to happen, it means that I fell in love with him from the first minute. It means that he is kind, noble and beautiful, and it was impossible not to love him. What should I do when I love him and love another? she said to herself, finding no answers to these terrible questions.
Iron oxides are compounds of iron with oxygen.
Three iron oxides are best known: iron (II) oxide - FeO, iron oxide (III) - Fe 2 O 3 and iron oxide (II, III) - Fe 3 O 4.
Iron(II) oxide
The chemical formula of ferrous oxide is - FeO . This connection is black.
FeO easily reacts with dilute hydrochloric acid and concentrated nitric acid.
FeO + 2HCl → FeCl 2 + H 2 O
FeO + 4HNO 3 → Fe(NO 3) 3 + NO 2 + 2H 2 O
It does not react with water and salts.
When interacting with hydrogen at a temperature of 350 ° C and coke at a temperature above 1000 ° C, it is reduced to pure iron.
FeO + H 2 → Fe + H 2 O
FeO + C → Fe + CO
Iron oxide (II) is obtained in various ways:
1. As a result of the reduction reaction of ferric oxide with carbon monoxide.
Fe 2 O 3 + CO → 2 FeO + CO 2
2. Heating iron at low oxygen pressure
2Fe + O 2 → 2 FeO
3. Decomposing ferrous oxalate in vacuum
FeC 2 O 4 → FeO + CO + CO 2
4. The interaction of iron with iron oxides at a temperature of 900-1000 o
Fe + Fe 2 O 3 → 3 FeO
Fe + Fe 3 O 4 → 4 FeO
In nature, ferrous oxide exists as the mineral wustite.
In industry, it is used in the smelting of iron in blast furnaces, in the process of blackening (burning) of steel. It is included in the composition of dyes and ceramics.
Iron(III) oxide
Chemical formula Fe2O3 . It is a compound of ferric iron with oxygen. It is a red-brown powder. It occurs naturally as the mineral hematite.
Fe2O3 has other names: iron oxide, iron minium, crocus, pigment red 101, food coloringE172 .
Does not react with water. It can interact with both acids and alkalis.
Fe 2 O 3 + 6HCl → 2 FeCl 3 + 3H 2 O
Fe 2 O 3 + 2NaOH → 2NaFeO 2 + H 2 O
Iron oxide (III) is used for painting building materials: brick, cement, ceramics, concrete, paving slabs, linoleum. It is added as a dye to paints and enamels, to printing inks. Iron oxide is used as a catalyst in the production of ammonia. In the food industry, it is known as E172.
Iron oxide (II, III)
Chemical formula Fe 3 O 4 . This formula can be written in another way: FeO Fe 2 O 3.
In nature, it is found as a mineral magnetite, or magnetic iron ore. It is a good conductor of electric current and has magnetic properties. It is formed during the combustion of iron and under the action of superheated steam on iron.
3Fe + 2 O 2 → Fe 3 O 4
3Fe + 4H 2 O → Fe 3 O 4 + 4H 2
Heating at a temperature of 1538 ° C leads to its decay
2Fe 3 O 4 → 6FeO + O 2
Reacts with acids
Fe 3 O 4 + 8HCl → FeCl 2 + 2FeCl 3 + 4H 2 O
Fe 3 O 4 + 10HNO 3 → 3Fe(NO 3) 3 + NO 2 + 5H 2 O
Reacts with alkalis when fused
Fe 3 O 4 + 14NaOH → Na 3 FeO 3 + 2Na 5 FeO 4 + 7H 2 O
Reacts with atmospheric oxygen
4 Fe 3 O 4 + O 2 → 6Fe 2 O 3
Recovery occurs by reaction with hydrogen and carbon monoxide
Fe 3 O 4 + 4H 2 → 3Fe + 4H 2 O
Fe 3 O 4 + 4CO → 3Fe + 4CO 2
Magnetic nanoparticles of Fe 3 O 4 oxide have found application in magnetic resonance imaging. They are also used in the production of magnetic media. Iron oxide Fe 3 O 4 is part of paints that are produced specifically for warships, submarines and other equipment. Fused magnetite is used to make electrodes for some electrochemical processes.
