Ammonia: composition, structure, properties, application

Lukusha Elena Fedorovna, teacher of chemistry, MBOU "Morskaya high school» Sudak Urban District, Republic of Crimea

Ammonia may owe its name to the oasis of the god Ammon in North Africa, located at the crossroads of caravan routes.

In very hot climates, urea (NH 2) 2 CO decomposes especially quickly.

One of the main degradation products is ammonia.

Oasis "Ammon"

in North Africa

According to some other sources, ammonia could get its modern name from the ancient Egyptian word "Amonian".

That's what everyone was called

believing people worshiping the god Amun.

People during their ritual rites sniffed NH 4 Cl, which emits the smell of ammonia when heated.

God Ammon in the form of a ram

The abbreviated name "ammonia", which we always use, was introduced in 1801 by a Russian scientist - chemist, academician

Yakov Dmitrievich Zakharov, who also developed the system of Russian chemical nomenclature for the first time.

covalent polar

chemical bond

Crystal cell

molecular

Physical Properties(at n.c.)

• colorless gas

with a sharp characteristic odor (the smell of ammonia)

• lighter than air (M=17 g/mol)
• very soluble in water (1200 volumes at 0 °C) and 700 volumes (at 20 °C) in a volume of water
• melting temperature -77.73°C
• boiling temperature -33.34°C

• POISONOUS!

Getting ammonia

To obtain ammonia in the laboratory use the action of strong alkalis on ammonium salts:

2NH 4 Cl + Ca(OH) 2 = 2NH 3 + CaCl 2 + 2H 2 O

(NH 4 ) 2 SO 4 + 2NaOH = 2NH 3 + Na 2 SO 4 + 2H 2 O

Ammonium hydroxide is an unstable base, decomposes:

NH 4 OH ↔ NH 3 + H 2 O

When receiving ammonia, it is necessary to keep the test tube - the receiver upside down, since ammonia ... ..

Industrial method for obtaining ammonia based on the direct interaction of hydrogen and nitrogen:

N2(g) + 3H2(g) ↔ 2NH3(g) + 45.9 kJ

catalyst - porous iron

temperature - 450 - 500 ˚С

pressure - 25 - 30 MPa

This is the so-called Haber process (German physicist, developed the physico-chemical foundations of the method).

Chemical properties of ammonia

For ammonia, reactions are characteristic:

1) with a change in the degree of oxidation of the nitrogen atom (oxidation reactions);

2) without changing the oxidation state of the nitrogen atom (addition).

Reactions with a change in the oxidation state of the nitrogen atom (oxidation reactions)

N -3 → N 0 → N +2

NH3 - strong reducing agent

with oxygen

Combustion of ammonia (when heated)

4NH 3 + 3O 2 → 2N 2 + 6H 2 0

catalytic oxidation ammonia (catalyst Pt - Rh, temperature)

4NH 3 + 5O 2 → 4NO + 6H 2 O

with metal oxides

2NH 3 +3CuO =3Cu + N 2 +3H 2 O

with strong oxidants

2NH 3 + 3Cl 2 = N 2 + 6HCl

(when heated)

Reactions without changing the oxidation state of the nitrogen atom (addition - the formation of an ammonium ion NH 4 +

according to the donor-acceptor mechanism

Interaction with acids

NH 3 + HCl → NH 4 Cl

2NH 3 +H 2 SO 4 → (NH 4 ) 2 SO 4

Interaction with water

NH 3 + H 2 O=NH 4 Oh

When phenolphthalein is added, the solution becomes crimson, since when ammonia is dissolved, ammonium hydroxide NH 4 OH is partially formed.

Application of ammonia

• Plastics and

fibers

2. As part of detergents

3. Production of nitrogen fertilizers

4. In agriculture

5. Production of nitric acid

6. Receipt explosives

This is interesting

• Vapors of ammonia can change the color of flowers. For example, blue And blue petals become green , bright red - black.

• Jupiter's clouds are made up of ammonia.

HISTORICAL BACKGROUND Ammonia was first obtained in its pure form in 1774 by the English chemist Joseph Priestley. In 1784, the French chemist Claude Louis Berthollet, using an electric discharge, decomposed ammonia into elements and thus established the composition of this gas, which in 1787 received official name"ammoniac" - from Latin name ammonia - sal ammoniac; this salt was obtained near the temple of the god Amun in Egypt. Joseph Priestley Claude Louis Berthollet

HISTORICAL SUMMARY This name is still preserved in most Western European languages ​​(German Ammoniak, English ammonia, French ammoniaque); the abbreviated name "ammonia" that we use was introduced in 1801 by the Russian chemist Yakov Dmitrievich Zakharov, who first developed the system of Russian chemical nomenclature. Oasis of Ammon in North Africa Remains of the Temple of Ammon

The pungent smell of ammonia has been known to man since prehistoric times, since this gas is formed in significant quantities during the decay, decomposition and dry distillation of nitrogen-containing organic compounds, such as urea or proteins. It is possible that on early stages The evolution of the Earth in its atmosphere was quite a lot of ammonia. Even now, however, minute amounts of this gas can always be found in the air and in rainwater, since it is continuously formed during the decomposition of animal and vegetable proteins. On some planets solar system the situation is different: astronomers believe that a significant part of the masses of Jupiter and Saturn falls on solid ammonia. HISTORICAL REFERENCE

STRUCTURE OF THE AMMONIA MOLECULE Nitrogen is a more electronegative element than hydrogen, therefore, when a bond is formed N-H common electron pairs "shift" to the nitrogen atom. Each N-H bond becomes polar, so the ammonia molecule as a whole is polar. Another thing is clear from the electronic formula: the nitrogen atom has a free (lone) pair of electrons. This further increases the polarity of the ammonia molecule and determines many of the properties of ammonia.

PHYSICAL PROPERTIES OF AMMONIA colorless gas has a pungent odor pungent taste 1.7 times lighter than air at T = -33.4 0 C liquefies at T = -77.7 0 C solidifies dissolves in alcohols, benzene, acetone is highly soluble in water ( in 1 V of water - 700 V of ammonia) Solubility of ammonia in water H2OH2O NH3

PHYSIOLOGICAL EFFECTS ON THE HUMAN BODY According to the physiological effect on the body, it belongs to the group of substances with an asphyxiant and neurotropic effect, capable of causing toxic pulmonary edema and severe injury in case of inhalation damage. nervous system. Ammonia vapor strongly irritates the mucous membranes of the eyes and respiratory organs, as well as the skin. This is what we perceive as a pungent smell. Ammonia vapors cause profuse lacrimation, pain in the eyes, chemical burns of the conjunctiva and cornea, loss of vision, coughing fits, redness and itching of the skin. When liquefied ammonia and its solutions come into contact with the skin, a burning sensation occurs, a chemical burn with blisters and ulcerations is possible. In addition, liquefied ammonia absorbs heat during evaporation, and frostbite of varying degrees occurs when it comes into contact with the skin.

CHEMICAL PROPERTIES OF AMMONIA (associated with changes in nitrogen oxidation state) 1. Decomposition of ammonia: ? N -3 H 3 + \u003d N? H Combustion of ammonia: ? N-3H? O 2 0 = ? N? H 2 O -2 + Q 3. Catalytic oxidation of ammonia: ? N-3H? O 2 0 = ? N+2O+? H 2 O -2 + Q Combustion of ammonia in oxygen Task: draw up an electronic balance, indicate the oxidizing agent / reducing agent, the process of oxidation / reducing agent NH 4 Cl, Ca (OH) 2 KMnO 4 O2O2 NH3

CHECK YOURSELF! 1) 2 N -3 H 3 + \u003d N H N e \u003d N oxidation / reducing agent 3 2H + + 2e \u003d H 2 0 - reduction / oxidizing agent 2) 4 N -3 H O 2 0 \u003d 2 N H 2 O -2 + Q 2 2N e \u003d N oxidation / reducing agent 3 O e \u003d 2O -2 - reduction / oxidizing agent 3) 4 N -3 H O 2 0 \u003d 4 N +2 O + 6 H 2 O -2 + Q 4 N e \u003d N +2 - oxidation / reducing agent 5 О e \u003d 2О -2 - reduction / oxidizing agent

CHEMICAL PROPERTIES OF AMMONIA (associated with the features of the covalent polar bond in the ammonia molecule) 1) Interaction with water: .. NH3 + HOH NH 4 OH 2) Interaction with acids: .. NH3 + HCl NH 4 Cl Ammonium hydroxide or "ammonia chloride" Chloride ammonium or "ammonia", "smelling salt" Conclusion: ammonia has basic (alkaline) properties

AMMONIA PRODUCTION To obtain ammonia in the laboratory, the action of strong alkalis on ammonium salts is used: NH 4 Cl + NaOH \u003d NH 3 + NaCl + H 2 O. The industrial method for obtaining ammonia is based on the direct interaction of hydrogen and nitrogen: N 2 (g) + 3H 2 (d) 2NH 3 (g) + 45.9 kJ This is the so-called Haber process (German physicist, developed the physicochemical basis of the method). NH 4 Cl, Ca(OH) 2 NH3

APPLICATION OF AMMONIA Used for the production of nitrogen fertilizers (ammonium nitrate and sulfate, urea), explosives and polymers, nitric acid, soda (ammonia method) and other chemical products. Liquid ammonia is used as a solvent. In refrigeration, it is used as a refrigerant.

APPLICATION OF AMMONIA In medicine, a 10% solution of ammonia, often called ammonia, is used for fainting (to stimulate respiration), to stimulate vomiting, as well as external neuralgia, myositis, insect bites, and treatment of the surgeon's hands. To excite breathing and bring the patient out of fainting, a small piece of gauze or cotton wool moistened with ammonia is carefully brought to the patient's nose (for 0.5–1 s). The physiological effect of ammonia is due to the pungent smell of ammonia, which irritates specific receptors of the nasal mucosa and excites the respiratory and vasomotor centers of the brain, causing increased breathing and increased blood pressure.

SOURCES OF INFORMATION 0%D0%9A&imgurl= 1.jpg&imgrefurl= =__u8g4E- 8evya8zce7LvnS2LQ09lo=&h=245&w=300&sz=10&hl=en&zoom=1&um=1&itbs=1 &tbnid=xErS9lz4l8rcjM:&tbnh=9 5&tbnw=116&prev=/images%3Fq%3D%25D0 %25 90%25D0%259C%25D0%259C%25D0%2598%25D0%2590%25D0%259A%26start%3 D108%26um%3D1%26hl%3Dru%26newwindow%3D1%26sa%3DN%26ndsp%3D18%26tbs %3Disch:1&start=117&um=1&newwindow=1&sa=N&ndsp=18&tbs=isch:1 #tbnid=xErS9lz4l8rcjM&start=121

slide presentation

Slide text: Lesson topic: Ammonia “You can not love chemistry, but you cannot live without it today and tomorrow” O.M. Nefyodov

Slide text: Meet ammonia HNO3 production Medicine A product of protein metabolism in living organisms Fertilizer production Detergents Hair dye Coolant in refrigerators Today, ammonia is an extremely important raw material for the production of nitrogen-containing substances used in agriculture, chemistry, medicine, military affairs And no less important, it is one of the products of protein metabolism in the body.

Slide text: History of the discovery of ammonia In the middle of the Libyan desert stood a temple dedicated to the god Amon Ra. In ancient times, Arab alchemists obtained colorless crystals from the Amon oasis, located near the temple. ground in mortars, heated - and received a caustic gas. At first it was called ammonia, and then the name was shortened to "ammonia". In the 18th century, ammonia was discovered by the English chemist Joseph Priestley. Today, ammonia is an extremely important raw material for the production of nitrogen-containing substances used in agriculture, chemistry, medicine, and military affairs. And no less important, it is one of the products of protein metabolism in the body.

Slide text: Production of ammonia (NH3) t NH4Cl+ Ca(OH)2 CaCl2+2NH3+2H2O Fe,t,p N2+ 3H2 2NH3+ Q

Slide text: Physical properties of ammonia NH3 NH3 ammonia is a gas: colorless, with a characteristic odor, lighter than air (collected in a vessel turned upside down) NH3 - TOXIC! Liquid ammonia causes severe skin burns; usually it is transported in steel cylinders (painted in yellow, have the inscription "Ammonia" in black) Ammonia - 3-10% ammonia solution Ammonia water - 18-25% ammonia solution Ammonia-air mixture is explosive!

Slide text: The structure of the ammonia molecule ▪ ▪ ▪ H * * * H H │ N ▪▪ The nitrogen atom, due to its three unpaired electrons, forms 3 covalent polar bonds with hydrogen atoms => the valence N is equal to III The unshared electron pair of the nitrogen atom is able to participate in the formation the fourth covalent bond with atoms having a vacant (free) orbital according to the donor-acceptor mechanism. The valency of N is IV Mechanism of donor-acceptor bond: H3N: + H+ = + ammonium ion

Slide text: Chemical properties of ammonia Reactions that occur with a change in the oxidation state of nitrogen NH3 is a strong reducing agent without changing the oxidation state of nitrogen NH3 is a weak base 1. ammonia is an unstable compound, decomposes when heated: 2NH3 N2 + 3H2 2. ammonia burns in oxygen: NH3 + O2 → N2 + H2O 3. oxidation of ammonia with air oxygen in the presence of a catalyst: NH3 + O2 NO + H2O Pt, Rh ammonia reacts with water: NH3 + H2O NH4OH NH4+ + OH− ammonium hydroxide ammonia reacts with acids: NH3 + HCl → NH4Cl ammonium chloride

Slide text: Good old ammonia, He is rich and he is poor, Rich in his unshared electrons, But only, that's the trouble, he's bored alone in solution. He is always ready to take a walk: There is acid, and here is water... Then, robbed to the skin, He cries: “Where are my belongings? What an iniquity: I have become an ammonium cation!”

Ammonia

Tasks to repeat

• Carry out a chain of transformations:
• N 2 →Li 3 N→NH 3 →NO→NO 2 →HNO 3

• Determine the coefficients in the reaction equation using the electron balance method:
• Determine the coefficients in the reaction equation using the electron balance method:

• NH 3 + O 2 → NO + H 2 O
• NH 3 + O 2 → N 2 + H 2 O

This story took place during World War I.

The structure of ammonia

(NH 3 )

+7 N ))

+1 h)

Physical Properties

• Ammonia - This colorless gas with sharp smell, 2 times lighter than air .

• Ammonia should not be inhaled for a long time, because. He poisonous.
• It liquefies easily.
• On contact with the skin, frostbite of varying degrees occurs.
• T pl = -78 0 WITH
• Highly soluble in water:

a) 25% solution - aqueous ammonia (ammonia water)

B) 10% solution - ammonia.

T kip = -33,5 0 WITH

Chemical properties

• According to the donor-acceptor mechanism:

A) Interaction with acids:

NH 3 + HCl \u003d NH 4 Cl

:NH 3 +□H + = NH 4 +

B) Interaction with water:

NH 3 + H 2 O ↔ NH 4 OH

ACCEPTOR

DONOR

Chemical properties

2) Interaction with metals:

2NH 3 + Na \u003d NaNH 2 + H 2

2NH 3 + O 2 \u003d 2H 2 O + N 2

2NH 3 + 3Br 2 \u003d 6HBr + N 2

Ammonia production

1) Industrial: synthesis from nitrogen and hydrogen:

N 2 + 3H 2 ↔2NH 3

2) Laboratory:

Ca (OH) 2 + NH 4 Cl \u003d CaCl 2 + NH 3 + 2H 2 O

Receipt

In the laboratory

NH 3

NH 4 Cl

Ca(OH) 2

Application

Production of nitrogen

In refrigeration

installations.

In medicine,

for soldering

Production

fertilizer

Production

explosive

Check of knowledge

1. What is the oxidation state of nitrogen in ammonium nitrate?

2. Write the chemical equations for the following transformations:

nitrogen→ammonia→ammonium chloride

3. Additional task: Determine the coefficients in the following chemical reaction scheme using the electron balance method:

Cu + NH 3 → N 2 + Cu + H 2 O

Homework

1 slide

Lesson topic: Ammonia “You can not love chemistry, but you can’t live without it today and tomorrow” O.M. Nefyodov

2 slide

Meet ammonia production of HNO3 Medicine A product of protein metabolism in living organisms Fertilizer production Detergents Hair dye Coolant in refrigerators Today, ammonia is an extremely important raw material for the production of nitrogen-containing substances used in agriculture, chemistry, medicine, military affairs. And no less important, it is one of the products of protein metabolism in the body.

3 slide

The history of the discovery of ammonia In the middle of the Libyan desert stood a temple dedicated to the god Amon Ra. In ancient times, Arab alchemists obtained colorless crystals from the Amon oasis, located near the temple. ground in mortars, heated - and received a caustic gas. At first it was called ammonia, and then the name was shortened to "ammonia". In the 18th century, ammonia was discovered by the English chemist Joseph Priestley. Today, ammonia is an extremely important raw material for the production of nitrogen-containing substances used in agriculture, chemistry, medicine, and military affairs. And no less important, it is one of the products of protein metabolism in the body.

4 slide

5 slide

Physical properties of ammonia NH3 NH3 ammonia - gas: colorless, with a characteristic odor, lighter than air (collected in a vessel turned upside down) NH3 - TOXIC! Liquid ammonia causes severe skin burns; usually it is transported in steel cylinders (painted yellow, have the inscription "Ammonia" in black) Ammonia - 3-10% ammonia solution Ammonia water - 18 -25% ammonia solution The mixture of ammonia with air is explosive!

6 slide

The structure of the ammonia molecule ▪ ▪ ▪ H * * * H H │ N ▪▪ The nitrogen atom, due to its three unpaired electrons, forms 3 covalent polar bonds with hydrogen atoms => valence N is equal to III The unshared electron pair of the nitrogen atom is able to participate in the formation of the fourth covalent bond with atoms having a vacant (free) orbital according to the donor-acceptor mechanism. The valency of N is IV Mechanism of donor-acceptor bond: H3N: + H+ = + ammonium ion

7 slide

Chemical properties of ammonia Reactions that occur with a change in the oxidation state of nitrogen NH3 is a strong reducing agent without changing the oxidation state of nitrogen NH3 is a weak base 1. ammonia is an unstable compound, decomposes when heated: 2NH3 N2 + 3H2 2. ammonia burns in oxygen: NH3 + O2 → N2 + H2O 3. oxidation of ammonia with air oxygen in the presence of a catalyst: NH3 + O2 NO + H2O Pt, Rh ammonia reacts with water: NH3 + H2O NH4OH NH4+ + OH− ammonium hydroxide ammonia reacts with acids: NH3 + HCl → NH4Cl ammonium chloride

8 slide

Good old ammonia, He is rich and he is poor, Rich in his unshared electrons, But only, that's the trouble, he's bored alone in solution. He is always ready to take a walk: There is acid, and here is water... Then, robbed to the skin, He cries: “Where are my belongings? What an iniquity: I have become an ammonium cation!”