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Homework: 1. Exercise 4 on p. 83 2. Complete test tasks
32,25,22,31,13,35,13,35,22,13,11,22,42,14, 34,25,34,24,21 1 2 3 4 5 10 to 20 a i v d r 30 m p ch o n 40 i s k b i
Independent work Task: Give names to the oxides Option 1: C uO Na 2 O CO 2 N 2 O 5 Na 2 O ZnO Option 2: M gO Al 2 O 3 P 2 O 5 Fe 2 O 3 Cu2O CaO
Option 1: C uO – copper oxide Na 2 O – sodium oxide CO 2 – carbon oxide N 2 O 5 – nitrogen oxide ZnO – zinc oxide Option 2: M gO – magnesium oxide Al 2 O 3 – aluminum oxide P 2 O 5 – phosphorus oxide Fe 2 O 3 - iron oxide CaO - calcium oxide
Oxygen has a destructive effect: with its participation, metals are oxidized with the formation of rust, plant and animal residues rot, and metal burns. Some processes are slow, others are very fast. In nature, the oxygen cycle occurs constantly, so its reserves are constantly being restored.
In nature, there is only one reaction as a result of which molecular oxygen is released from its compounds - photosynthesis. As you already know from your biology course, plant leaves carry out the nutrition process in the light with the help of chlorophyll. At the same time, glucose is synthesized from H 2 O and CO 2 and oxygen is formed.
This process also occurs in seaweed. The plant world annually returns about 400 billion tons of oxygen to the atmosphere. Oxygen released into the atmosphere, in turn, oxidizes elements on the Earth's surface. Consequently, these compounds form zones of the earth's crust.
IN METALLURGY, FOR CUTTING AND WELDING METALS Oxygen is used in metallurgy in the production of steel. Also, in many metallurgical units, for more efficient combustion of fuel, instead of air in the burners, an oxygen-air mixture is used, i.e. enrich the air with oxygen.
Steel production
Oxygen in cylinders is widely used for flame cutting and welding of metals. Combustible acetylene gas, burning in a stream of oxygen, allows you to get temperatures above 3000°C! This is approximately twice the melting point of iron.
Fuel oxidizer Oxygen, which is part of the air, is used to burn fuel: for example, in the engines of cars, diesel locomotives and ships. Liquid oxygen is used as an oxidizer for rocket fuel. A mixture of liquid oxygen and liquid ozone is one of the most powerful oxidizers of rocket fuel.
Use for medical purposes Oxygen has also found its use in medicine. Oxygen is used to enrich respiratory gas mixtures in case of breathing problems, to treat asthma, and to prevent hypoxia in the form of oxygen cocktails and oxygen pillows. However, you cannot breathe pure oxygen at normal pressure for a long time - this is dangerous to health.
Applications in the food industry In the food industry, oxygen is registered as a food additive E948, as a propellant and packaging gas. Propellants are gases that force food products out of a container (container, spray can, tank or storage facility for bulk products).
Independent work 1. Make up formulas for the following oxides: iron (II) oxide, sulfur (IV) oxide, hydrogen oxide, copper (II) oxide 2. Complete the equations for the following reactions: C + O 2 → Mg + O 2 → 3. Calculate the mass fraction of each element in the compound NO 2
On the topic: methodological developments, presentations and notes
“Properties, production and use of oxygen”
Lesson in 8th grade on the topic “Properties, production and use of oxygen” Objectives: 1. Study of the physical, chemical properties of oxygen, methods of its production, use....
“Obtaining hydrogen and oxygen” (using pedagogical technology for the development of critical thinking).
Lesson on the topic “Obtaining hydrogen and oxygen” (using pedagogical technology for the development of critical thinking). Purpose: - To introduce methods of obtaining, collecting and detecting hydrogen and oxygen....
“Chemical properties and applications of hydrogen and oxygen” (using pedagogical technology for the development of critical thinking).
Lesson on the topic “Chemical properties and applications of hydrogen and oxygen” (using pedagogical technology for the development of critical thinking). Goal: - Continue to develop knowledge of the concepts of “oxidation state ...
Oxygen Oxygen is an element of the main subgroup of the sixth group, the second period of the periodic system of chemical elements of D.I. Mendeleev, with atomic number 8. Denoted by the symbol O (lat. Oxygenium). Oxygen is a chemically active non-metal and is the lightest element of the chalcogen group. The simple substance oxygen (CAS number:) under normal conditions is a colorless, tasteless and odorless gas, the molecule of which consists of two oxygen atoms (formula O 2), and therefore it is also called dioxygen. Liquid oxygen is light blue in color.
There are other allotropic forms of oxygen, for example, ozone (CAS number:) under normal conditions, a blue gas with a specific odor, the molecule of which consists of three oxygen atoms (formula O 3).
History of the discovery It is officially believed that oxygen was discovered by the English chemist Joseph Priestley on August 1, 1774 by decomposing mercury oxide in a hermetically sealed vessel (Priestley directed the sun's rays at this compound using a powerful lens). 2HgO (t) 2Hg + O 2
However, Priestley initially did not realize that he had discovered a new simple substance; he believed that he had isolated one of the constituent parts of air (and called this gas “dephlogisticated air”). Priestley reported his discovery to the outstanding French chemist Antoine Lavoisier. In 1775, A. Lavoisier established that oxygen is a component of air, acids and is found in many substances.
A few years earlier (in 1771), oxygen was obtained by the Swedish chemist Karl Scheele. He calcined saltpeter with sulfuric acid and then decomposed the resulting nitric oxide. Scheele called this gas “fire air” and described his discovery in a book published in 1777 (precisely because the book was published later than Priestley announced his discovery, the latter is considered the discoverer of oxygen). Scheele also reported his experience to Lavoisier.
Finally, A. Lavoisier finally figured out the nature of the resulting gas, using information from Priestley and Scheele. His work was of enormous importance because thanks to it, the phlogiston theory, which was dominant at that time and hampered the development of chemistry, was overthrown. Lavoisier conducted experiments on the combustion of various substances and disproved the theory of phlogiston, publishing results on the weight of the elements burned. The weight of the ash exceeded the original weight of the element, which gave Lavoisier the right to claim that during combustion a chemical reaction (oxidation) of the substance occurs, and therefore the mass of the original substance increases, which refutes the theory of phlogiston. Thus, the credit for the discovery of oxygen is actually shared between Priestley, Scheele and Lavoisier.
Origin of the name The word oxygen (also called “acid solution” at the beginning of the 19th century) owes its appearance in the Russian language to some extent to M.V. Lomonosov, who introduced the word “acid”, along with other neologisms; thus, the word “oxygen”, in turn, was a tracing of the term “oxygen” (French l "oxygène), proposed by A. Lavoisier (Greek όξύγενναω from ξύς “sour” and γενναω “give birth”), which is translated as “generating acid ", which is due to its original meaning of "acid", which previously meant oxides, called oxides according to modern international nomenclature.
Occurrence in nature Oxygen is the most common element on Earth; its share (in various compounds, mainly silicates) accounts for about 47.4% of the mass of the solid earth's crust. Sea and fresh waters contain a huge amount of bound oxygen 88.8% (by mass), in the atmosphere the content of free oxygen is 20.95% by volume and 23.12% by mass. More than 1,500 compounds in the earth's crust contain oxygen. Oxygen is part of many organic substances and is present in all living cells. By the number of atoms in living cells it is about 25%, and by mass fraction it is about 65%.
Obtaining Currently, in industry, oxygen is obtained from air. Laboratories use industrially produced oxygen, supplied in steel cylinders under a pressure of about 15 MPa. The most important laboratory method for its production is electrolysis of aqueous solutions of alkalis. Small amounts of oxygen can also be obtained by reacting a solution of potassium permanganate with an acidified solution of hydrogen peroxide. Oxygen plants operating on the basis of membrane and nitrogen technologies are also well known and successfully used in industry. When heated, potassium permanganate KMnO 4 decomposes to potassium manganate K 2 MnO 4 and manganese dioxide MnO 2 with the simultaneous release of oxygen gas O 2: 2KMnO 4 K2MnO 4 + MnO 2 + O 2
In laboratory conditions, it is also obtained by the catalytic decomposition of hydrogen peroxide H 2 O 2: 2H 2 O 2 2H 2 O + O 2 The catalyst is manganese dioxide (MnO 2) or a piece of raw vegetables (they contain enzymes that accelerate the decomposition of hydrogen peroxide). Oxygen can also be obtained by the catalytic decomposition of potassium chlorate (Berthollet salt) KClO 3: 2KClO 3 2KCl + 3O 2 In addition to the above laboratory method, oxygen is obtained by the method of air separation in air separation plants with a purity of up to 99.9999% in O 2.
Physical properties Under normal conditions, oxygen is a colorless, tasteless, and odorless gas. 1 liter of it weighs 1.429 g. Slightly heavier than air. Slightly soluble in water (4.9 ml/100g at 0 °C, 2.09 ml/100g at 50 °C) and alcohol (2.78 ml/100g at 25 °C). It dissolves well in molten silver (22 volumes of O 2 in 1 volume of Ag at 961 °C). Is paramagnetic. When gaseous oxygen is heated, its reversible dissociation into atoms occurs: at 2000 °C 0.03%, at 2600 °C 1%, 4000 °C 59%, 6000 °C 99.5%. Liquid oxygen (boiling point 182.98 °C) is a pale blue liquid. Phase diagram O 2 Solid oxygen (melting point 218.79 °C) blue crystals. Six crystalline phases are known, three of which exist at a pressure of 1 atm:
α-O 2 exists at temperatures below 23.65 K; bright blue crystals belong to the monoclinic system, cell parameters a=5.403 Å, b=3.429 Å, c=5.086 Å; β=132.53° β-O 2 exists in the temperature range from 23.65 to 43.65 K; pale blue crystals (with increasing pressure the color turns pink) have a rhombohedral lattice, cell parameters a=4.21 Å, α=46.25° γ-O 2 exists at temperatures from 43.65 to 54.21 K; pale blue crystals have cubic symmetry, lattice parameter a=6.83 Å
Three more phases are formed at high pressures: δ-O 2 temperature range up to 300 K and pressure 6-10 GPa, orange crystals; ε-O 2 pressure from 10 to 96 GPa, crystal color from dark red to black, monoclinic system; ζ-O 2 pressure is more than 96 GPa, a metallic state with a characteristic metallic luster, at low temperatures it transforms into a superconducting state.
Chemical properties Strong oxidizing agent, interacts with almost all elements, forming oxides. Oxidation state 2. As a rule, the oxidation reaction proceeds with the release of heat and accelerates with increasing temperature. An example of reactions occurring at room temperature: 4K + O 2 2K 2 O 2Sr + O 2 2SrO Oxidizes compounds that contain elements with a non-maximum oxidation state: 2NO + O 2 2NO 2
Oxygen does not oxidize Au and Pt, halogens and inert gases. Oxygen forms peroxides with oxidation state 1. For example, peroxides are obtained by combustion of alkali metals in oxygen: 2Na + O 2 Na 2 O 2 Some oxides absorb oxygen: 2BaO + O 2 2BaO 2
According to the combustion theory developed by A. N. Bach and K. O. Engler, oxidation occurs in two stages with the formation of an intermediate peroxide compound. This intermediate compound can be isolated, for example, when a flame of burning hydrogen is cooled with ice, along with water, hydrogen peroxide is formed: H 2 + O 2 H 2 O 2 Superoxides have an oxidation state of 1/2, that is, one electron for two oxygen atoms (ion O 2 -). It is obtained by reacting peroxides with oxygen at elevated pressures and temperatures: Na 2 O 2 + O 2 2NaO 2 Ozonides contain the O 3 - ion with an oxidation state of 1/3. It is obtained by the action of ozone on alkali metal hydroxides: KOH(solid) + O 3 KO 3 + KOH + O 2 The dioxygenyl ion O 2 + has an oxidation state of +1/2. Obtained by the reaction: PtF 6 + O 2 O 2 PtF 6
Oxygen fluorides Oxygen difluoride, OF 2 oxidation state +2, is obtained by passing fluorine through an alkali solution: 2F 2 + 2NaOH OF 2 + 2NaF + H 2 O Oxygen monofluoride (Dioxydifluoride), O 2 F 2, unstable, oxidation state +1. It is obtained from a mixture of fluorine and oxygen in a glow discharge at a temperature of 196 °C. By passing a glow discharge through a mixture of fluorine and oxygen at a certain pressure and temperature, mixtures of higher oxygen fluorides O 3 F 2, O 4 F 2, O 5 F 2 and O 6 F 2 are obtained. Oxygen supports the processes of respiration, combustion, and decay. In its free form, the element exists in two allotropic modifications: O 2 and O 3 (ozone).
Application Chemistry, petrochemistry: Creation of an inert environment in containers, nitrogen fire extinguishing, purging and testing of pipelines, regeneration of catalysts, packaging of products in a nitrogen environment, intensification of oxidation processes, release of methane, hydrogen, carbon dioxide.
1 slide
The presentation was prepared by Roxana Smirnova, a 9th grade student at the Lyceum of Otradnoye.
2 slide
Oxygen as an element. 1. The element oxygen is in group VI, main subgroup, period II, serial number No. 8, 2. Atomic structure: P11 = 8; n01 = 8; ē = 8 valency II, oxidation state -2 (rarely +2; +1; -1). 3. Part of oxides, bases, salts, acids, organic substances, including living organisms - up to 65% by weight.
3 slide
Oxygen as an element. Oxygen is the most common element on our planet. By weight, it accounts for approximately half of the total mass of all elements of the earth's crust. Air composition: O2 – 20-21%; N2 – 78%; CO2 – 0.03%, the rest comes from inert gases, water vapor, and impurities. 4. In the earth's crust it is 49% by mass, in the hydrosphere - 89% by mass. 5. Composed of air (in the form of a simple substance) – 20-21% by volume. 6. Included in most minerals and rocks (sand, clay, etc.). Composed of air (in the form of a simple substance). 7. A vital element for all organisms, found in most organic substances, involved in many biochemical processes that ensure the development and functioning of life. 8. Oxygen was discovered in 1769-1771. Swedish chemist K.-V. Scheele
4 slide
Physical properties. Oxygen is a chemically active non-metal and is the lightest element from the group of chalcogens. The simple substance oxygen under normal conditions is a colorless, tasteless and odorless gas, the molecule of which consists of two oxygen atoms, for which reason it is also called dioxygen. Liquid oxygen is light blue in color, while solid oxygen is light blue crystals.
5 slide
Chemical properties. With non-metals C + O2 CO2 S + O2 SO2 2H2 + O2 2H2O With complex substances 4FeS2 + 11O2 2Fe2O3 + 8SO2 2H2S + 3O2 2SO2 + 2H2O CH4 + 2O2 CO2 + 2H2O With metals 2Mg + O2 2MgO 2Cu + O2 –t 2CuO Interaction of substances with oxygen is called oxidation. All elements react with oxygen except Au, Pt, He, Ne and Ar; in all reactions (except for the interaction with fluorine), oxygen is an oxidizing agent. 1. Unstable: O3 O2 + O 2. Strong oxidizing agent: 2KI + O3 + H2O 2KOH + I2 + O2 Discolors dyes, reflects UV rays, destroys microorganisms.
6 slide
Methods of obtaining. Industrial method (distillation of liquid air). Laboratory method (decomposition of some oxygen-containing substances) 2KClO3 –t ;MnO2 2KCl + 3O2 2H2O2 –MnO2 2H2O + O2
7 slide
Checking the collected oxygen. Obtaining 3O2 2O3 During a thunderstorm (in nature), (in the laboratory) in an ozonizer of potassium permanganate when heated: 2KMnO4 –t K2MnO4 + MnO2 + O2 The decomposition of this salt occurs when it is heated above 2000 C.
8 slide
Applications of oxygen: It is widely used in medicine and industry. During high-altitude flights, pilots are provided with special oxygen devices. For many pulmonary and heart diseases, as well as during operations, oxygen is given to inhale from oxygen cushions. Submarines are supplied with oxygen in cylinders. The combustion of loose combustible material impregnated with liquid oxygen is accompanied by an explosion, which makes it possible to use oxygen in blasting operations. Liquid oxygen is used in jet engines, in autogenous welding and metal cutting, even under water.
That gas is worthy of surprise - It is being used now For cutting metals, in steelmaking And in powerful blast furnaces. The pilot takes it to high altitudes. The submariner takes it with him. You probably already guessed it, What is this gas...
Oxygen
Lesson topic: Oxygen. Receipt. Properties.
The purpose of the lesson: Study the history of discovery, the main methods of production and properties of oxygen.
Lesson plan:
- The meaning of oxygen. Biological role.
2. Prevalence in nature.
3. History of discovery.
4. Position of the oxygen element in PSHE D.I. Mendeleev.
5. Physical properties.
6. Obtaining oxygen
7. Chemical properties.
8. Use of oxygen.
Joseph Priestley
(1743 – 1794)
Karl Scheele
(1742 – 1786)
Antoine Lavoisier
(1743 – 1794)
t = – 1 83 °C
t = –219 °C
Pale blue liquid
Gas, colorless, odorless, tasteless, slightly soluble in water
Blue crystals
Heavier than air.
Light, chlorophyll
6СО 2 + 6H 2 ABOUT
WITH 6 N 12 ABOUT 6 + 6O 2
Liquefaction of air under pressure at t = – 1 83 °C
By repression V air
By displacing water
Water decomposition
H 2 O H 2 +O 2
Hydrogen peroxide decomposition
H 2 O 2 H 2 O+O 2
Decomposition of potassium permanganate
KMnO 4 K 2 MnO 4 +MnO 2 +O 2
potassium permanganate
potassium manganate
Decomposition of Berthollet salt (potassium chlorate)
KClO 3 KCl + O 2
Oxygen is obtained in the laboratory by decomposition of oxygen-containing compounds
With simple substances:
With non-metals:
S+O 2 SO 2
P+O 2 P 2 O 5
With metals:
Mg+O 2 MgO
Fe+O 2 Fe 3 O 4 (FeO Fe 2 O 3 )
When simple substances interact with oxygen, oxides are formed
Think and answer
A
1
b
2
V
3
G
4
d
5
Think and answer
- Scientists involved in the production and study of oxygen:
a) Dmitry Ivanovich Mendeleev;
b) Joseph Priestley;
c) Antoine Laurent Lavoisier;
d) Karl Scheele;
d) Mikhail Vasilievich Lomonosov
Think and answer
2. Three different flasks contain air, carbon dioxide, and oxygen. You can recognize each of the gases:
a) comparing the masses of flasks filled with gases
b) using a smoldering splinter
c) by the solubility of gases in water
d) by smell
e) with the help of other substances
Think and answer
3. In the laboratory, oxygen is obtained:
a) air liquefaction
b) decomposition of water
c) decomposition of potassium permanganate
d) from hydrogen peroxide
e) oxidation of substances
Think and answer
4. Oxygen can be collected by displacing water because it:
a) lighter than air
b) highly soluble in water
c) heavier than air
d) poorly soluble in water
d ) has no color, smell, taste
Think and answer
5. We are talking about oxygen as a simple substance:
a) oxygen is part of water;
b) oxygen is poorly soluble in water;
c) oxygen supports respiration and combustion;
d) is a component of air;
e) is part of carbon dioxide.
A
1
2
b
V
3
G
4
d
5
Ar(O)=16 nonmetal B= II
t = – 1 83 °C
Pale blue liquid
Me Neme
t = –219 °C
in industry: air cooling to -183 °C
oxidation
E X ABOUT at
Blue crystals
in the laboratory:
H 2 O H 2 O 2 KMnO 4 KClO 3
Collection methods:
Air displacement
Water displacement
Homework
§3 2–34
"3" - With. 111 questions 1,2
"4" - With. 111 questions 3.4
"5" - With. 111 questions 5.6
Task: It is known that the human body contains 65% oxygen by weight. Calculate how much oxygen is in your body.
Creative task:
Compose a crossword, rebus, VOC on the topic “Oxygen”
Slide 2
OXYGEN
Oxygen is the 16th element of the main subgroup of group VI, the second period of D.I. Mendeleev’s periodic system of chemical elements, with atomic number 8. It is designated by the symbol O (lat. Oxygenium). Oxygen is a chemically active non-metal and is the lightest element from the group of chalcogens. The simple substance oxygen under normal conditions is a colorless, tasteless and odorless gas, the molecule of which consists of two oxygen atoms (formula O2), for which reason it is also called dioxygen. Liquid oxygen is light blue in color, while solid oxygen is light blue crystals.
Slide 3
It is officially believed that oxygen was discovered by the English chemist Joseph Priestley on August 1, 1774 by decomposing mercuric oxide in a hermetically sealed vessel (Priestley directed sunlight at this compound using a powerful lens). However, Priestley initially did not realize that he had discovered a new simple substance; he believed that he had isolated one of the constituent parts of air (and called this gas “dephlogisticated air”). Priestley reported his discovery to the outstanding French chemist Antoine Lavoisier. In 1775, A. Lavoisier established that oxygen is a component of air, acids and is found in many substances. A few years earlier (in 1771), oxygen was obtained by the Swedish chemist Karl Scheele. He calcined saltpeter with sulfuric acid and then decomposed the resulting nitric oxide. Scheele called this gas “fire air” and described his discovery in a book published in 1777 (precisely because the book was published later than Priestley announced his discovery, the latter is considered the discoverer of oxygen). Scheele also reported his experience to Lavoisier. An important step that contributed to the discovery of oxygen was the work of the French chemist Pierre Bayen, who published works on the oxidation of mercury and the subsequent decomposition of its oxide. Finally, A. Lavoisier finally figured out the nature of the resulting gas, using information from Priestley and Scheele. His work was of enormous importance because thanks to it, the phlogiston theory, which was dominant at that time and hampered the development of chemistry, was overthrown. Lavoisier conducted experiments on the combustion of various substances and disproved the theory of phlogiston, publishing results on the weight of the burned elements. The weight of the ash exceeded the original weight of the element, which gave Lavoisier the right to claim that during combustion a chemical reaction (oxidation) of the substance occurs, and therefore the mass of the original substance increases, which refutes the theory of phlogiston. Thus, the credit for the discovery of oxygen is actually shared between Priestley, Scheele and Lavoisier. DISCOVERY OF OXYGEN
Slide 4
Slide 5
Use of oxygen Widespread industrial use of oxygen began in the mid-twentieth century, after the invention of turboexpanders - devices for liquefaction and separation. The use of oxygen is very diverse and is based on its chemical properties. Chemical and petrochemical industry. Oxygen is used to oxidize the starting reactants, producing nitric acid, ethylene oxide, propylene oxide, vinyl chloride and other basic compounds. In addition, it can be used to increase the productivity of waste incinerators. Oil and gas industry. Increasing the productivity of oil cracking processes, processing high-octane compounds, injection into the reservoir to increase displacement energy.
Slide 6
Application of oxygen
Glass industry. Glass melting furnaces use oxygen to improve combustion. In addition, it is used to reduce nitrogen oxide emissions to safe levels. Pulp and paper industry. Oxygen is used in delignification, alcoholization and other processes. In medicine, medical oxygen is stored in high-pressure metal gas cylinders (for compressed or liquefied gases) of blue color of various capacities from 1.2 to 10.0 liters under pressure up to 15 MPa (150 atm) and is used to enrich respiratory gas mixtures in anesthesia equipment, in case of breathing problems, for relieving an attack of bronchial asthma, eliminating hypoxia of any origin, for decompression sickness, for treating pathologies of the gastrointestinal tract in the form of oxygen cocktails. For individual use, special rubberized containers - oxygen cushions - are filled from cylinders with medical oxygen. Oxygen inhalers of various models and modifications are used to supply oxygen or an oxygen-air mixture simultaneously to one or two victims in the field or in a hospital setting. The advantage of an oxygen inhaler is the presence of a condenser-humidifier of the gas mixture, which uses the moisture of the exhaled air. To calculate the amount of oxygen remaining in the cylinder in liters, the pressure in the cylinder in atmospheres (according to the pressure gauge of the reducer) is usually multiplied by the cylinder capacity in liters. For example, in a cylinder with a capacity of 2 liters, the pressure gauge shows an oxygen pressure of 100 atm. The volume of oxygen in this case is 100 × 2 = 200 liters.