Does air have weight? Density and specific volume of moist air How much does a liter of air weigh.

Compressed air is air under pressure greater than Atmosphere pressure.

Compressed air is a unique energy carrier along with electricity, natural gas and water. In industrial conditions, compressed air is mainly used to drive devices and mechanisms with a pneumatic drive (pneumatic drive).

In everyday, everyday life, we practically do not notice the Air around us. However, throughout human history, people have used unique properties air. Invention of the sail and the forge windmill and hot air balloon were the first steps in the use of air as an energy carrier.

With the invention of the compressor, the era of industrial use has come compressed air. And the question: what is Air, and what properties does it have? - became far from idle.

When starting to design a new pneumatic system or upgrade an existing one, it would be useful to recall and about some properties of air, terms and units of measurement.

Air is a mixture of gases, mainly composed of nitrogen and oxygen.

Average relative molar mass-28.98 . 10 -3 kg/mol

*Composition of air may vary. As a rule, in industrial areas, the air contains

Air is an intangible quantity, it is impossible to feel it, smell it, it is everywhere, but for a person it is invisible, it is not easy to find out how much air weighs, but it is possible. If the surface of the Earth, as in a children's game, is drawn into small squares, 1x1 cm in size, then the weight of each of them will be 1 kg, that is, 1 cm 2 of the atmosphere contains 1 kg of air.

Can it be proven? Quite. If you build a scale from an ordinary pencil and two balloons, fixing the design on the thread, the pencil will be in balance, since the weight of the two inflated balls is the same. It is worth piercing one of the balls, the advantage will be in the direction of the inflated ball, because the air from the damaged ball has come out. Accordingly, a simple physical experience proves that air has a certain weight. But if we weigh the air flat surface and in the mountains, then its mass will be different - the mountain air is much lighter than the one we breathe near the sea. reasons different weight several:

The weight of 1 m 3 of air is 1.29 kg.

• the higher the air rises, the more rarefied it becomes, that is, high in the mountains, the air pressure will not be 1 kg per cm 2, but half as much, but the content of oxygen necessary for breathing also decreases exactly by half, which can cause dizziness, nausea and ear pain;
• water content in the air.

The composition of the air mixture includes:

1. Nitrogen - 75.5%;

2. Oxygen - 23.15%;

3. Argon - 1.292%;

4. Carbon dioxide - 0.046%;

5. Neon - 0.0014%;

6. Methane - 0.000084%;

7. Helium - 0.000073%;

8. Krypton - 0.003%;

9. Hydrogen - 0.00008%;

10. Xenon - 0.00004%.

The number of ingredients in the composition of air can change and, accordingly, the mass of air also undergoes changes in the direction of increase or decrease.

• Air always contains water vapor. The physical pattern is such that the higher the air temperature, the more water it contains. This indicator is called air humidity and affects its weight.

How is the weight of air measured? There are several indicators that determine its mass.

How much does a cube of air weigh?

At a temperature equal to 0 ° Celsius, the weight of 1 m 3 of air is 1.29 kg. That is, if you mentally allocate a space in a room with a height, width and length equal to 1 m, then this air cube will contain exactly this amount of air.

If air has weight and weight that is palpable enough, why doesn't a person feel heaviness? Such physical phenomenon, as atmospheric pressure, implies that an air column weighing 250 kg presses on each inhabitant of the planet. The area of ​​the palm of an adult, on average, is 77 cm 2. That is, in accordance with physical laws, each of us holds 77 kg of air in the palm of our hand! This is equivalent to the fact that we constantly carry 5 pound weights in each hand. AT real life even a weightlifter cannot do this, however, each of us can easily cope with such a load, because atmospheric pressure presses from both sides, both outside the human body and from the inside, that is, the difference is ultimately equal to zero.

The properties of air are such that it affects the human body in different ways. High in the mountains, due to lack of oxygen, visual hallucinations occur in people, and at great depths, the combination of oxygen and nitrogen into a special mixture - “laughing gas” can create a feeling of euphoria and a feeling of weightlessness.

Knowing these physical quantities, it is possible to calculate the mass of the Earth's atmosphere - the amount of air that is held in near-Earth space by gravity. The upper boundary of the atmosphere ends at a height of 118 km, that is, knowing the weight of m 3 of air, you can divide the entire borrowed surface into air columns, with a base of 1x1m, and add up the resulting mass of such columns. Ultimately, it will be equal to 5.3 * 10 to the fifteenth degree of tons. The weight of the planet's air armor is quite large, but even it is only one millionth of the total mass. the globe. The Earth's atmosphere serves as a kind of buffer that keeps the Earth from unpleasant cosmic surprises. From only one solar storms that reach the surface of the planet, the atmosphere loses up to 100 thousand tons of its mass per year! Such an invisible and reliable shield is air.

How much does a liter of air weigh?

A person does not notice that he is constantly surrounded by transparent and almost invisible air. Is it possible to see this intangible element of the atmosphere? Visually, moving air masses is broadcast daily on a television screen - warm or cold front brings long-awaited warming or heavy snowfall.

What else do we know about air? Probably, the fact that it is vital for all living beings living on the planet. Every day a person inhales and exhales about 20 kg of air, a quarter of which is consumed by the brain.

The weight of air can be measured in different physical quantities, including liters. The weight of one liter of air will be equal to 1.2930 grams, at a pressure of 760 mm Hg. column and a temperature of 0°C. In addition to the usual gaseous state, air can also occur in liquid form. For the transition of a substance into a given state of aggregation will require exposure to enormous pressure and very low temperatures. Astronomers suggest that there are planets whose surface is completely covered with liquid air.

The sources of oxygen necessary for human existence are the Amazon forests, which produce up to 20% of this important element on the entire planet.

Forests are truly the “green” lungs of the planet, without which human existence is simply impossible. Therefore alive houseplants in an apartment are not just an interior item, they purify the air in the room, the pollution of which is ten times higher than on the street.

Clean air has long become a shortage in megacities, the pollution of the atmosphere is so great that people are ready to buy clean air. For the first time, “air sellers” appeared in Japan. They produced and sold clean air in cans and any resident of Tokyo could open a jar of the purest air for dinner and enjoy its freshest aroma.

Air purity has a significant impact not only on human health, but also on animals. In polluted areas of equatorial waters, near populated areas, dozens of dolphins are dying. The reason for the death of mammals is a polluted atmosphere; in the autopsy of animals, the lungs of dolphins resemble the lungs of miners clogged with coal dust. Very sensitive to air pollution and the inhabitants of Antarctica - penguins, if the air contains a large number of harmful impurities, they begin to breathe heavily and intermittently.

For a person, air cleanliness is also very important, so after working in the office, doctors recommend taking daily one-hour walks in the park, forest, and outside the city. After such "air" therapy, vitality the body is restored and well-being improves significantly. The recipe for this free and effective medicine has been known since ancient times, many scientists, rulers considered daily walks in the fresh air to be an obligatory ritual.

For a modern urban dweller, air treatment is very relevant: a small portion of life-giving air, the weight of which is 1-2 kg, is a panacea for many modern ailments!

What is the density of air at 150 degrees Celsius in kg/m3, g/cm3, g/ml, lb/m3 . Don't forget that this physical quantity, characteristic of air, as its density in kg/m3 (the mass of a unit volume of atmospheric gas, where 1 m3, 1 cubic meter, 1 cubic meter, 1 cubic centimeter, 1 cm3, 1 milliliter, 1 ml or 1 pound is taken as a unit volume), depends on several parameters. Among the parameters describing the conditions for determining the air density (specific gravity of air gas), I consider the following to be the most important and must be taken into account:

1. Temperature air gas.
2. Pressure at which the density of the air gas was measured.
3. Humidity air gas or the percentage of water in it.

If you are interested in the second case air density at T = 150 degrees C, then excuse me, but I have no desire to copy tabular data, a huge special reference book for air density at various pressures. I cannot yet decide on such a colossal amount of work, and I do not see the need for it. See reference book. Narrow profile information or rare special data, density values, should be sought in primary sources. So smarter.

It is more realistic, and probably more practical from our point of view, to indicate what is the density of air at 150 degrees Celsius, for a situation where the pressure is given by a constant and is atmospheric pressure(under normal conditions - the most popular question). By the way, do you remember what normal atmospheric pressure is? What does it equal? Let me remind you that normal atmospheric pressure is considered to be 760 mm Hg, or 101325 Pa (101 kPa), in principle, this is normal conditions corrected for temperature. Meaning, what is the density of air in kg/m3 at a given temperature air gas you will see, find, learn in table 1.

However, it must be said that the values ​​indicated in the table air density values ​​at 150 degrees in kg/m3, g/cm3, g/ml, will not be true for any atmospheric, but only for dry gas. As soon as we change the initial conditions and change the humidity of the air gas, it will immediately have different physical properties. And its density (weight of 1 cubic meter of air in kilograms) at given temperature in degrees C (Celsius) (kg/m3) will also differ from the dry gas density.

Physics at every step Perelman Yakov Isidorovich

How much does the air in the room weigh?

Can you say at least approximately what kind of load is the air that your room contains? A few grams or a few kilograms? Are you able to lift such a load with one finger, or would you barely keep it on your shoulders?

Now, perhaps, there are no longer people who think, as the ancients believed, that air weighs nothing at all. But even now many cannot say how much a certain volume of air weighs.

Remember that a liter mug of air of the density that it has near earth's surface at normal room temperature, it weighs about 1.2 g. Since a cubic meter contains 1 thousand liters, a cubic meter of air weighs a thousand times more than 1.2 g, namely 1.2 kg. It is now easy to answer the question posed earlier. To do this, you just need to find out how many cubic meters are in your room, and then the weight of the air contained in it will be determined.

Let the room have an area of ​​10 m 2 and a height of 4 m. In such a room there are 40 cubic meters of air, which weighs, therefore, forty times 1.2 kg. This will be 48 kg.

So, even in such a small room, the air weighs a little less than yourself. It would not be easy for you to carry such a load on your shoulders. And the air of a room twice as large, loaded onto your back, could crush you.