What is the property of fresh air? What is air made of? Composition and properties. Chemical properties of air
What is air made of. Air is everywhere around us, although we do not see it. It fills all voids, cracks and pores underground and on the surface. There is air in the water, so fish can live in reservoirs, which, like all living things, breathe oxygen. It covers the entire planet. The air shell of the Earth is called the atmosphere. Air does not disperse into outer space because it is held by gravity. Therefore, the atmosphere rotates together with the Earth as a whole.
Air is a mixture of gases. It contains the most nitrogen (3/4) and oxygen (less than 1/4). There are very few other gases (Fig. 106).
| Atmosphere |
Each gas is of great importance for life on Earth. Oxygen is essential for all living things to breathe. Carbon dioxide, which is present in a small amount in the air, is called a "insulator": it has the ability to transmit the sun's rays to the Earth, and keep it warm.
In addition, the air contains water vapor. It also contains various solid impurities: dust, ash from forest fires and volcanic eruptions, ice crystals and sea salt, soot. For example, over deserts there is a lot of dust in the air, over oceans - salt crystals, over major cities- soot.
Air It is a mixture of gases, the main ones being nitrogen and oxygen. In a small amount in the air there is carbon dioxide, water vapor and solid impurities (dust, ash, soot).
Air properties. The air is colorless and transparent. Explore the properties of air.
 |
| Rice. 106. Composition of air |
Experience 1. Take an empty plastic bottle from under the water, close it tightly with a cork and squeeze it from the sides. It is not possible to noticeably squeeze the bottle. This is because it is not empty, as it seemed, but filled with air. Through the cork, it cannot spread outward. Open the cork and re-compress. This can be done without much effort.
Experience 2. Let's direct the hole of an open empty plastic bottle to a lit candle and squeeze it from the sides. We will see that the flame is swaying, although we have not touched the candle. The flame was affected by the air displaced from the bottle. So we checked that air really, like any substance in a gaseous state of aggregation, fills the vessel and easily spreads beyond it. material from the site
Experience 3. one plastic bottle, filled with water, and tightly close the second empty one with corks and put it in a bowl of water. We will observe how the water bottle will quickly sink to the bottom, while the empty one will float on the surface. This proves that air is light.
Air can be compressed and is resilient (remember how a rubber ball filled with compressed air bounces off the floor). It is also known that air is a poor conductor of heat. This property protects the Earth from excessive heating. sunbeams and cooling.
What is the difference between your winter jacket and autumn or summer jacket? The winter jacket has down or porous synthetic winterizer material. Such materials have a lot of air between the fluffs or in the pores, which keeps you warm and does not let the cold in. Therefore, in winter you are not cold in downy or fur clothes thanks to the air.
Air - colorless, transparent, light, elastic. It fills the entire space and conducts heat poorly.
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On this page, material on the topics:
- essay air mixture gas
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A message about air for children will tell you what air is, what are the properties of air and what is the role of air. The story about the air for children can be supplemented with interesting facts.
Air Report
Without air, there would be no life on Earth. Air is essential for all living things to breathe. plants, animals, and humans. Air is mixture of gases. Air contains nitrogen, carbon dioxide, and oxygen.
Air fills everything vacancies and even the smallest cracks. A transparent glass only seems empty. Try, slowly tilting it, immerse it in water. As the glass fills with water, air will come out of it in large bubbles.
The importance of air in nature and human life
1) Air is necessary for a person to breathe
2) Plants need air for photosynthesis
3) Animals need air to breathe
4) Air is necessary for the breathing of the inhabitants of the aquatic environment
5) Air is used in industry to burn fuel
6) Air is used in everyday life to burn fuel
7) Under the action of air and bacteria, obsolete organic matter converted into minerals.
8) Air is needed for weathering rocks and for soil formation
Also, thanks to the air, airplanes, helicopters, birds fly. The lift that keeps them in flight comes from air flowing around the curved surfaces of their wings.
The air ocean surrounding our planet is held by the forces of the earth's gravity. If the Earth lost its air shell, it would turn into a lifeless, devoid of vegetation, desert.
What is air made of?
Air is a mixture of gases. Imagine that the circle is all the air on your planet. Let's divide it conditionally into 4 parts. Most of your air, ¾ (three-quarters), is a gas called nitrogen. But for breathing you need another gas - oxygen. It is slightly less than ¼ part in the composition of air. The rest of the air is made up of other gases, among which a significant part is carbon dioxide. You give off carbon dioxide when you breathe.
What are the properties of air?
- Air is invisible and colorless.
- Fresh air has no smell.
- The air has no taste
- Air has no shape.
- Air is elastic
- Air is lighter than water, that is, less dense than water.
- Air is a poor conductor of heat.
- Air expands when heated and contracts when cooled.
Where is the cleanest and healthiest air?
Our breathing requires clean air with sufficient oxygen content. But in cities where all the roads are clogged with cars, the air is polluted by their exhaust gases. Add pollution and emissions from plants and factories.
But in forests and parks it is very easy to breathe, because our green helpers absorb harmful carbon dioxide and release oxygen. Algae also produce oxygen, which is why the air on the sea coast is so healing.
But now people are trying to reduce harmful emissions into the atmosphere. Are being created car engines working on electric and even solar energy. Instead of smoking heat pipes, nuclear and solar power plants are being built.
Knowledge of the world Grade 3
Subject:
Goals :
Lesson type:
Expected Result : Students should have an idea about the composition of air, be aware of its properties.
A- have an idea about air and its properties, are able to analyze the properties of air;
B- can analyze, show creative and practical abilities, prove their point of view, answer questions high level evaluate their work.
C- ask high-level questions, organize the guys in a group, critically evaluate their activities through self-reflection
Concepts: experiment, experience.
Teaching Methods
The form:
Modules:
Equipment: the guest - Balloon, a basket, tables (according to the number of students), a glass, water, water straws, a ball, a fan, a candle, a stick with foil, a globe, perfume, red and green pencils (according to the number of students),small pieces of paper, lumps of soil, chalk,lesson presentation
During the classes:
1. Organizational moment.
The bell rang loudly
The lesson starts.
Came to class - do not frown,
Have fun to the end!
Training "Wave"
Instruction. “Join hands. Now I will start the wave like this (shows, raising his hand). Your task is when the wave reaches you, let it go further. Let's try ... Now I'm launching an oncoming wave.
Conduct procedure. The group becomes in a circle. Participants join hands. The host gives instructions and shows how the waves start: he raises his hand, holding the hand of a neighbor. There was a wave. To pass it on, the neighbor needs to raise the second hand with the hand of his neighbor, etc. The leader speeds up the rhythm of the waves. Then it launches counter waves. When the wave returns to the coach, he can either pass it on or stop it.
As soon as the interest of the group begins to weaken (laughter subsides, energy subsides), the trainer stops the warm-up, abruptly raising and throwing his hands down. The warm-up ends with applause.
2. Introduction to the topic of the lesson.
Guys, I want to ask you: “Is it more interesting to look for answers to difficult questions alone or with friends?
(with friends)
I agree with you completely. (1 verse of V. Shainsky's song "When my friends are with me" sounds).
Guys, guess who I invited with me to the lesson?
He will be the main character of our lesson.
Round, smooth, like a watermelon.
Any color for different tastes.
If you let go of the leash -
Fly away for the clouds.
(answers)
Meet - this is a Balloon.Take one of the balloons on the table and draw your mood.
3. Message of the topic of the lesson.
In the last lesson we talked about water and its properties. Let's repeat a little.
What properties of water do you know?
In addition to the Atlantic, Pacific, Indian and Arctic oceans, there is another one in the world - the largest of all oceans, and you, every day, every hour, every minute, without noticing it, "bath" in it.
- And passers-by on the street, and cats, and dogs, and pigeons, even trams with trolleybuses day and night "bathe" in this ocean. Guess what the ocean is? Not? Then I'll tell you: the ocean is not salty, not fresh, and besides, without shores and without water. Like huge silvery fish, planes float through its expanses. Now you must have understood. Well, of course, we are talking about the largest - the blue air ocean.
-Four water oceans spread wide, wide over the earth, and the fifth air ocean - above the earth. The bottom of this ocean of air is the Earth itself.
Have you seen the air?
What is the name of the earth's atmosphere?(atmosphere)
4. Work on cards.
Read more about atmosphere.
1. The air shell of the planet is necessary for breathing.
2. Air does not allow the earth's surface to overheat from the Sun and at the same time protects its heat from dissipating into space.
3. Atmosphere - reliable protection our planet from meteorites.
4. The atmosphere protects the Earth, vegetation and animal world from the destructive influence of cosmic radiation.
Read the most important.
Conclusion! Everything matters.
- Today we will open the secrets of the air.
5. Air composition.
What do you think air is made of?
Air is a mixture of gases. The air contains the most nitrogen, the least oxygen, and the least amount of carbon dioxide.
How do you figure out which of the gases in the air is the most important?
Inhale air and exhale. We breathe in air that contains oxygen, and we breathe out air without oxygen. It becomes more carbon dioxide, which is not suitable for breathing.
So, why do all living things need air? (to breathe, to live)
Does a person use all the air for his breathing?
More than two hundred years ago, French chemist Antoine Lavoisier proved that air is basically a mixture of two gases, nitrogen and oxygen.
Nitrogen means "lifeless". This part of the air does not support breathing and combustion. But without nitrogen, plants cannot grow.
Oxygen - a person is able to live for weeks without food, several days without water, and without air - at most 5 minutes. However, to be precise, it is not the air itself that is needed, but only the element contained in it - oxygen. A person is not able to live without oxygen, because without it the cells of the body cannot exist. The exceptional importance of air is explained by the fact that our body does not know how to extract oxygen from a liquid or solid. And from the air, i.e. from gas - he can. By the way, there is less oxygen in the air than in water or soil.
Widely used in economic activity oxygen: when fuel is burned in the engines of cars, aircraft, ships. Pharmacies give out oxygen bags to sick people. Newborn babies who have difficulty breathing are placed in an oxygen cuvette.
inert gases.
Later, at the end of the 19th century, studies proved that 5 more simple gaseous substances are part of the air:argon, helium, krypton, xenon, neon . These gases are calledinert (inactive)
What does "inert person" mean? (Inactive)
They learned how to obtain inert gases by chemical means and use them in the national economy.
The lightness and flammability of helium is used when filling balloons and airships.
In an argon environment, electric welding of metals is carried out.
Light bulbs are filled with neon, argon, krypton, xenon.
A mixture of helium and oxygen is used for breathing during underwater work.
In addition, the air containscarbon dioxide . It is essential for plant nutrition. A person breathes oxygen and emits carbon dioxide, i.e. spent oxygen. And plants absorb this gas. Everyone needs large quantity plants to make the air cleaner.
Still in the airwater vapor and various impurities.
Guys, do you believe me that air is everywhere around us?
Does he exist at all? Maybe they invented it?
Shall we prove it? After all, whoever seeks will always find the answer even to the most difficult question!
So, let's begin. Imagine this picture:
It was a hot July day. The kid lay on a haystack and inhaled the aroma of heated grass. Insects chirped around, a falcon soared in the sky.
How do birds fly? And planes? asked the Kid. - What is the sky? What is it from?
The kid took a deep breath. The grass heated in the sun smelled, the wings of butterflies rustled, and the sky was so blue and bright that the baby closed his eyes and ... fell asleep. The boy dreamed that he was flying. Far below was a lawn. Birds were circling nearby, and then the Kid did not see anything anymore, he quickly flew to high clouds. And now he is already on a big white cloud. There the kid saw the inscription: "Welcome to the Laboratory of miraculous transformations of Air!"
So, where did we end up with the boy?
Who works in the laboratory? (scientists)
So today we will be scientists who study the air. And scientists record all their observations in a scientific diary.
Strategy"Fact or Opinion" - on the basis of experiments to investigate the properties of air.
1. In the classroom we see a board, a desk, walls, outside the window - houses, trees, clouds. Can wesee air?
Experience (students)
Take a straw and dip it into a glass of water. Lightly blow into the straw.
What has appeared?
will appearair bubbles.
Conclusion: With the help of vision, air can still be detected in some cases.
Look at indoor plants.
What color are they?
And the blackboard?
What color do you think the air is?
Opening the first property of air: airinvisible and colorless.
And here thick layer air has color. Look out the window.
What do you see above?
(Sky)
We are accustomed to call the ocean of air - the sky.
The blue sky is a thick layer of air illuminated by the sun. If the Earth were not surrounded by air, we would see the fiery disk of the Sun in the black sky.
The air ocean is very important for life. Because the air is breathed by people, animals, birds and plants - all living things on Earth.
Can a person live without air?
Cover your mouth and nose with your palms.
Take a deep breath and count how much you can without air.
What was the desire?
(open nose).
It's scary to even think what will happen if the air suddenly disappears. Without air, we will simply die.
- Now take a deep breath, what do you feel?
(Nothing).
Does the air smell like anything?
Close your eyes.
And now?
(Smell of perfume).
We smell when particles of a substance enter our nose.
Where do you smell strong odors?
(In the canteen, hairdresser, pharmacy, etc.)
So what is the conclusion?
Clean air has no smell.
Elastic
Bag experience.
Inflate the bag and pop.
Can you taste the air? Lick it.
What properties of air will we discover?
The air has no taste
4. Pick up a textbook. What shape is it? Now try to take the air in your hands. Happened?
Does air have a shape?
(No)
And now I ask you to fill in the table. What did you learn from our research about air?
Connect the words in the left column with the words in the right column with an arrow:
Air color
colorless
blue
fragrant
without smell
round
no shape
gas
liquid
The smell of the air
Air Shape
Air condition
Air is around us, but we do not notice it, because ...
PHYSMINUTKA (lying on the mat)
Are you tired?
The air will help you relax.
Ex.
"Flower field".
Now relax, imagine that you are in a forest clearing, surrounded by beautiful flowers. Pick the flower you like best. Smell it.
What word would express it fragrant aroma?
Take a deep breath and say (AH!)
6. Use of the properties of air by man.
Let's continue to study the properties of air and find out which of them a person uses.
Hit the ball on the floor. The air in the ball is compressed. But since the air is elastic, it tends to expand, and the ball bounces off the floor with force.
Air is compressible and elastic .
This property of air is widely used.
Connect with lines: who uses - how they use:
fire brakes
Painters strong water jet
Drivers splatter paint
Experience (teacher)
Come to me and see an experiment that proves that warm air rises.
(Warm air, rising up, sets the spiral in motion).
Have you proven that warm air rises?
T warm air rises
You can also see this property of air at home when warm air is chimney rises up.
People noticed this property of air and decided to use it to rise up. various items. So they came up with balloon.
He moved where the wind blew. Soon, scientists created a balloon that was equipped with a steering wheel, it could be controlled. Such a balloon was called an aerostat.
Balloon
Why do animals wear warm fluffy coats for winter?
(answers)
In fluffy fur coats between the villi there is more air, which retains heat.
Why do animals and birds hide in the snow in extreme cold?
(answers)
Although the snow is cold, there is air between the snowflakes. This air also protects animals from the cold.
So the air has another usefulproperty to keep warm.
Therefore, double frames are made in houses.
Keeps warm
So let's repeat what properties of air a person uses:
air is compressible and elastic
the air is moving
hot air rises
air will keep warm
Air, like any body, consists of particles, between which there are gaps. Particles are constantly moving, often colliding. When the air is heated, they begin to move faster, collide more strongly. Because of this, they bounce a long distance from each other. The gaps between them increase and the air expands.
Demonstration of experience.
We stretch the ball on the flask and bring it to the fire. After a while, we will see that the balloon began to inflate. Why?
Conclusion ! Air expands when heated .
Air compresses as it cools
Let's take the flask off the fire. What did you notice? Correctly. The air cooled in the flask and the balloon deflated.
I light 3 candles. We close one with a glass, the second with a jar, and leave the third open. What did we see? Which candle went out faster?
The candle under the glass quickly goes out, under the jar - later, and the uncovered candle continues to burn. Why?
- There is very little air under the glass and the candle quickly went out. There was more under the jar and the candle burned longer, but it also went out. And an open candle burns out completely.
- What does it say?
Air supports combustion.
- How many cases of fires were there in our village? What causes fires?
- In order to avoid trouble in our house, we need to carefully monitor electrical appliances, follow the safety rules when using gas cylinders, stoves and do not play with matches and combustible substances.
- To put out a fire, you need to stop the access of air to a burning object: cover it with sand, cover it with a blanket, cover it with foam from a fire extinguisher.
Oh, Balloon wants to sing you guys one more song. Let's hear what it is about? Maybe she is on the topic of the lesson?
(Verse 1 of the song “Ah, come on, sing a song to us a cheerful wind” sounds).
What is this song about? How is wind related to air?
Let's remember what we know about the wind?
The story of a trained student about the wind:
Land in different places differently heated by the sun. The air also heats up from the earth.
Warm air is lighter than cold air.
Warm air rises. BUT cold air falls in his place. This is where the wind comes in. Meanswind is the movement of air.
- It is necessary to put several small pieces of paper on the table and wave a newspaper over them.
What will happen? - Why?
- The air started to move and “picked up” the paper on its way.
Wave your fan around your face. What do you feel? We feel a light breeze.
So air is moving.
The air is moving
Air makes objects move and spin, forms waves, raises dust.
Think about how a person makes the wind help himself?
(Answers of children).
Man builds windmills wind farms. The wind blows the sails of the ships.
Breathing exercises.
1. Deep breath, exhale in portions.
2. Deep breath in, exhale with a hiss.
3. Deep breath - hands through the sides up, rise on toes, exhale - lower your hands down.
7. Environmental anxiety
Demonstration of experience.
I light a candle. What is visible? (Waves of air move over the flame.).
Let's take a plate. Let's keep a few centimeters from the flame
What did you see on the plate (Soot).
Soot comes from the combustion of fuel - in this case, wax.
Air pollution from incomplete combustion occurs. Now one candle was burning, and how much soot it gave!
How many of these candles - factory pipes around the planet? Great multitude.
How do smoke, fumes, poisonous soot affect the composition of the air? (The air gets polluted).
This problem is one of the most important at present.
Since there are many factories and plants that affect the composition of the air. There is a high incidence of people in this area.
What did you learn from the text about what people are doing to protect the purity of the air?
What can you do to keep the air clean?
Plants are essential for clean air. They play a huge role inair purification. They trap dust, soot. (Slide)
8. Air protection.
Guys, people and animals, factories and cars, everyone needs air. Why is it not getting smaller on earth?
(answers)
Because there are green plants on Earth. Man breathes in oxygen and breathes out carbon dioxide. And the plants seem to breathe carbon dioxide, and exhale oxygen, which is necessary for people and animals.
Guys, what can pollute the air?
(answers)
Mark with a red pencil what pollutes the air, in green - what does not pollute.
Tell us what causes air pollution?
(answers)
Many factories are being built in cities. From their pipes, smoke rises into the air, in which there is a lot of dust of toxic substances that are harmful to the health of all living beings.
Vehicle exhaust fumes also pollute the air.
What do people do to keep the air clean?
(answers)
Plants operate installations that trap dust and toxic gases. Scientists are developing new machines that will not pollute the air..
And green spaces are the main air purifier. That is why it is so easy to breathe in the forest.
Poplar alone emits as much oxygen as 3 lindens, 7 firs, 4 aspens.
9. Reflection.
Reflection "Method of five fingers"
M - little finger.
What knowledge did you gain today?
B - nameless
What did I do today and what did I achieve?
With - average
How can I help a classmate today?
At - index
What have I done today for my health?
B - large
What is your mood?
Well done boys. Friendly work in the lesson helped you learn a lot of interesting things about the air.
Let's try to live in such a way that on our planet - Earth, flowers always bloom and birds sing!
Now open your diaries for homework.
10. Homework(differentiated):
Weak: Prepare a report on the topic “Properties of air”.
Strengths: Make a crossword on the topic "Air and its properties",drawing "Air Protection"
11. Evaluation.
As a memento of the lesson, a friend Balloon gives you a piece of air with the mark that you earned in the lesson today.
If you agree with the rating. Clap your hands!
Thank you for the lesson! See you soon!
TEST:
1. What is air?
A) liquid
B) solid
B) mixture of gases
2. How long can a person go without air?
A) 5 weeks
B) 5 days
B) 5 minutes
3. Clean air:
A) white
B) transparent
B) blue
D) able to move
D) standing still
E) odorless
G) smells
H) light
I) heavy
K) has a temperature
L) has the shape of a ball
4. What measures outdoor thermometer?
A) body temperature
B) water temperature
B) the temperature of the earth
D) air temperature
5. At what air temperature is it very cold?
A) + 20 degrees
B) 0 degrees
C) - 20 degrees
6. Air movement is ...
A) leaf fall
B) wind
B) snow
7. Where does hot air go?
A) up
B) down
B) to the side
Lesson Analysis
Knowledge of the world Grade 3
There are 6 students in the 3rd grade. All the children were present at the lesson. Of these, 1 girl and 5 boys. The class is average in terms of performance (at the lesson of knowing the world).
The topic of the lesson was chosen in accordance with the calendar - thematic planning.
The educational material is selected in accordance with the State Standard and the educational, developing, educating tasks of the lesson.
Subject: Air and its properties. Air movement is wind.
Goals :
to acquaint with the composition of air, its properties;
to form students' knowledge about the air ocean of the Earth - the atmosphere;
develop communication skills and creativity through group work;
show the effect of pollution environment on human health;
talk about the measures taken to protect the purity of the air.
Lesson type: Lesson of studying and primary consolidation of new knowledge
Teaching Methods : informational; instructive; stimulating; encouraging; activity.
Work form: group work, pair work, frontal
Modules: 1. Use of ICT 2. New approaches 3. Teaching and learning in accordance with the age characteristics of students 4. Teaching talented and gifted children. 5. Teaching critical thinking.
The lesson formed the ability to highlight the main thing in educational material, problem tasks were used, a person-oriented approach was carried out.
used to attract attention visual material, reception of emotional presentation, change of intonation.
During the lesson, exercises were used to develop visual memory, visual-figurative thinking.
Individual, collective, group forms of work were used among students.
To relieve fatigue, tone the body, get positive emotions, set to overcome difficulties, psychological training "Wave", wellness minutes were held.
When carrying out all types of work, age and individual characteristics attention, memory, thinking, imagination, perception of students.
I believe that the lesson achieved its goal.
DEFINITION
Air is a mixture of gases dissolved in each other. The composition of the air includes nitrogen (78% by volume), oxygen (21% by volume), noble (inert) gases (about 1% by volume), carbon monoxide (IV), water vapor and various impurities.
Carbon dioxide is formed in nature as a result of the combustion of plant materials, the respiration of living organisms and decay. A large number of CO 2 enters the atmosphere as a result of human activities. Despite the constant supply of CO 2 to the atmosphere, its average content in the air is almost always at the level of 0.03% by volume.
Chemical properties of air
Due to the presence of oxygen in the composition of the air (21% by volume), which exhibits oxidizing properties, many substances are able to burn in the air, and the equations chemical reactions combustion (oxidation) of substances in (in) air is written as the equations of combustion of these substances in oxygen, since it is impossible to display on paper chemical composition air.
Physical properties of air
The main physical properties of air include temperature, relative humidity, density, specific heat, thermal conductivity, dynamic and kinematic viscosity and others. Almost all of these parameters are highly dependent on temperature, so there are special tables that indicate the values of the parameters characterizing physical properties air at specific temperatures.
Relative humidity is the ratio of water vapor contained in a unit of air to their maximum possible content at a given temperature and pressure. With an increase in pressure and a decrease in temperature, the value relative humidity air increases.
The density of air at 20C is 1.2 kg/m 3 , and when it is heated, it decreases significantly. So, when air is heated to a temperature of 1200C, the air density decreases by 5 times compared to the air density at 20C.
The viscosity of air strongly depends on temperature and increases with its growth, and both kinematic and dynamic viscosity increase. The values of kinematic and dynamic viscosity of air are interconnected through the value of its density.
The heat capacity of air also increases with increasing temperature, however, this physical parameter depends on temperature to a lesser extent than, for example, density. So, when air is heated from 20 to 1200C, the heat capacity of air increases only 1.2 times.
Other parameters characterizing the physical properties of air (thermal diffusivity, Prandtl number, etc.) do not depend on temperature changes.
Examples of problem solving
EXAMPLE 1
| Exercise | Determine the volume of air required for the complete oxidation of hydrogen sulfide with a volume of 448 liters. |
| Decision | The oxidizing power of air is due to the presence of oxygen in the air. The volume fraction of oxygen in the air is 21%, i.e. 1/5 of the total volume of air. Let us write the reaction equation for the complete oxidation of hydrogen sulfide by air oxygen: 2H 2 S + 3O 2 \u003d 2SO 2 + 2H 2 O Find the amount of hydrogen sulfide substance: v(H 2 S) = V(H 2 S)/V m v (H 2 S) \u003d 448 / 22.4 \u003d 20 mol According to the equation, the number of moles of oxygen: v (O 2) \u003d 1.5 × v (H 2 S) v(O 2) \u003d 1.5 × 20 \u003d 30 mol Find the volume of oxygen: V(O 2) \u003d v(O 2) × V m V (O 2) \u003d 30 × 22.4 \u003d 672 l Then the volume of air: V \u003d 672 × 5 \u003d 3360 l |
| Answer | Air volume - 3360 l |
EXAMPLE 2
| Exercise | Determine the volume of air required to burn 36 g of magnesium. |
| Decision | The oxidizing power of air is due to the presence of oxygen in the air. The volume fraction of oxygen in the air is 21%, i.e. 1/5 of the total volume of air. Let us write the reaction equation for the combustion of magnesium with atmospheric oxygen:
|