Composition of air - class-VII

The main component of air are oxygen and they will only react together at a normal temperature. For the formation of oxides of nitrogen, a very high temperature is required. 

In monsoon there is lot of humidity in air as compared to summer. Hence, the Clothes dry faster in summer than in monsoon

Warm air is lighter than cold air because they have more heat energy, which results in the increase in distances between the molecules. This decraeses the density, and hence makes it lighter than cold air.

Sea and land breezes are caused because of an uneven heating of the earth and through convection currents.

Dew are tiny drops of water that form on cool surfaces at night, when atmospheric vapour condenses.

Nitrogen is the major constituent of air. 

Argon is the most abundant and most used of the noble gases. Its chief uses are in metallurgy, where it provides an inert atmosphere in which hot metals can be worked. Because argon is so very unreactive, it prevents chemical reactions of the very hot metal being welded or forged.

Nitrogen constitutes nearly 78% of the atmosphere.

Nitrogen (N2) has a molar mass of approximately 28 g/mol, while air (a mixture of nitrogen and oxygen) has an average molar mass of approximately 29 g/mol. Therefore, nitrogen is slightly lighter than air, making the statement false.

The air in our atmosphere is composed of molecules of different gases. The most common gases are nitrogen (78%), oxygen (about 21%), and argon (almost 1%).

Nitrogen and oxygen gases are the major components of the atmosphere. Around 80% of the atmosphere is nitrogen and 20% is oxygen, by volume. 

Xenon is a noble gas present in the Earth's atmosphere in extremely low concentrations (about 0.087 ppm). While neon, helium, and argon are also inert, xenon is significantly rarer than the others listed.

Air consists of active and inactive components. This was proposed by Mayow in the year 1674.

Noble gases have the largest ionization potential among the elements of each period, which reflects the stability of their electron configuration and is related to their relative lack of chemical reactivity.

The noble gases have weak interatomic force, and consequently have very low melting and boiling points. They are all monatomic gases under standard conditions, including the elements with larger atomic masses than many normally solid elements.

The noble gases make a group of chemical elements with similar properties. For the first six periods of the periodic table, the noble gases are exactly the members of group 18 of the periodic table.

The abundances of the noble gases decrease as their atomic numbers increase. Helium is the most plentiful element in the universe except hydrogen. All the noble gases are present in Earths atmosphere and, except for helium and radon, their major commercial source is the air, from which they are obtained by liquefaction and fractional distillation.

An inert gas is a gas that is generally non-reactive with other substances. The term inert means non-reactive. We refer to gases as being chemically inert if their atoms don't combine with other atoms in chemical reactions.

All the noble gases have 8 electrons in their outermost shell except  Helium (He) which has only 2 electrons in its outermost shell.

When we refer to inert gases, we are usually referring to six primary ones, also called the noble gases. Meet the most common inert gases: helium $\left(He\right)$, argon $\left(Ar\right)$, neon $\left(Ne\right)$, krypton $\left(Kr\right)$, xenon $\left(Xe\right)$, and radon $\left(Rn\right)$.

Humidity is the amount of water vapour in the atmosphere. It is a significant aspect of atmosphere beacuse it effects the weather and climate.

Most atoms do not have 8 electrons in this outer orbital so they react with other atoms to form bonds to fill their outer electron orbital. The atomic structure of the noble gases is different from the structure of most atoms because they have a filled outer orbital.

Helium is used in balloons and airships. It is much less dense than air, so balloons filled with it float upwards.

$ { { (NH } _{ 2 }) } _{ 2 }{ Cr } _{ 2 }{ O } _{ 7 }\xrightarrow [ thermal\quad decomposition ]{ \Delta  } { Cr } _{ 2 }{ O } _{ 3 }+{ N } _{ 2 }+4{ H } _{ 2 }O\ N{ H } _{ 4 }{ NO } _{ 2 }\xrightarrow [ thermal\quad decomposition ]{ \Delta  } { N } _{ 2 }+2{ H } _{ 2 }O\ 2{ NaN } _{ 3 }\xrightarrow [ thermal\quad decomposition ]{ \Delta  } 2Na+3{ N } _{ 2 } $ 

Main constituent in air is nitrogen.
The proportion of nitrogen in the open air is 78% by volume.
Note:
Air
is a mixture of gases. The volume percent of nitrogen and oxygen are
78%and 21% respectively. Air also contains tiny amounts of carbon
dioxide, argon, methane, ozone and water vapour.

Argon is used in light bulbs. The very thin metal filament inside the bulb would react with oxygen and burn away if the bulb were filled with air instead of argon. Argon stops the filament burning away because it is unreactive.

Combustion can not take place without air. Air contains about 21% by volume of oxygen. Oxygen is essential for combustion to occur.

The thermal decomposition of sodium nitrite to produce sodium oxide(III), nitrogen and oxygen. This reaction takes place at a temperature of $700-900°C.$

$4NaN{ O } _{ 2 }→2{ Na } _{ 2 }O+2{ N } _{ 2 }+3{ O } _{ 2 }$

A mixture of nitrogen and carbon dioxide can be distinguished by passing it through lime water. Because nitrogen does not turn lime water milky and carbon dioxide forms carbonate with lime which makes lime water milky. From this we can conclude that nitrogen gas does not react with lime water, hence, it is most useful in removing nitrogen from air.

$ N{ H } _{ 4 }{ NO } _{ 2 }\xrightarrow [ thermal\quad decomposition ]{ \Delta  } { N } _{ 2 }+2{ H } _{ 2 }O $

 The exothermic oxidation of ammonia to nitrogen oxide and water vapour:

 $4N{ H } _{ 3 }+5{ O } _{ 2 }→4NO+6{ H } _{ 2 }O$

The atmosphere contains many gases, including some pollutants and greenhouse gases. The most abundant gas in the atmosphere is nitrogen, second oxygen . Argon, an inert gas, is the third most abundant gas in the atmosphere.

Nitrogen has small size and it is a typical non-metal. It is very difficult to identify. It can easily form a triple bond.

Inert gases are also known as zero-valent gases, zero group elements or noble gases. They have completely filled valence shell and are chemically unreactive.

At low temperatures nitrogen can be liquefied on compression.

Oxygen is returned to the atmosphere mainly by photosynthesis.

Nitrogen gas is neutral to litmus and is a non combustible nor supports combustion and can be liquefied on compression at low temperatures. It is non poisonous.

Nitrogen is not a supporter of COMBUSTION.
Nitrogen is a colorless, odorless, tasteless diatomic gas. It is found in Group 15 of the periodic table. It does not burn, does not support combustion, and is only slightly soluble in water. It is relatively inactive chemically, but many of its compounds display marked reactivity.

 In solid state, nitrogen occurs as chile saltpeter, saltpeter and sal ammoniac.
Chile saltpeter is sodium nitrate, $\displaystyle NaNO _3$.
Saltpeter is potassium nitrate, $\displaystyle KNO _3$
Sal ammoniac is ammonium chloride, $\displaystyle NH _4Cl$.

Nitrogen is a non supporter of combustion.
Nitrogen is a colorless, odorless, tasteless diatomic gas. It is found in Group 15 of the periodic table. It does not burn, does not support combustion.

Air has fixed composition with less oxygen at high altitudes. Air contains 78% nitrogen and 21% oxygen and less than 1% He, Ar, Ne and water vapor content. This composition remains fixed at all locations but the oxygen becomes less dense at high altitudes so it is difficult to breathe in such low concentration of air.

Sea breeze is defined as a breeze blowing towards the land from the sea, especially during the day owing to the relative warmth of the land.

The earth's atmosphere gets thinner with the increase in altitude. The earth's atmospheric layers are Troposphere, Stratosphere, Mesosphere, Ionosphere, and Exosphere. Each layer has its own importance. 

Mountaineers carry oxygen cylinder along with them because when they climb mountains, as altitude increase, the amount of oxygen level in the atmospheric air decreases as trees are not found at higher altitude.

It is not proper to breathe through our mouth because most of the dust particles can enter our body along with the air we breathe in. But breathing through nose does have this because nose has hair present which traps the dust particles.

By volume dry air contains $78.09%$ Nitrogen, $20.95%$ Oxygen, $0.93%$ Argon, $0.04%$ Carbon dioxide and small traces of other gases.

The proportion of nitrogen in the open air is 78% by volume.
Note:
Air is a mixture of gases. The volume percent of nitrogen and oxygen are 78%and 21% respectively. Air also contains tiny amounts of carbon dioxide, argon, methane, ozone and water vapour.

Nitrogen$(N _2)$, Carbon dioxide$(CO _2)$, Oxygen$(O _2)$, Ozone$(O _3)$ are part of the atmosphere but chlorine$(Cl _2)$ is not a part of atmosphere.

Oxygen is a chemical element, with the symbol O. Several allotropes, or molecular forms, of it exist, but the three most common in our environment are molecular oxygen, or dioxide, O₂

Air contains some gases, water vapours and dust particles that stick to a transparent glass of windows and it appears hazy. 

By volume dry air contains $78.09%$ Nitrogen, $20.95%$ Oxygen, $0.93%$ Argon, $0.04%$ Carbon dioxide and small traces of other gases.

The percentage of Nitrogen in air is $78%$.

Air is composed of various gases in different proportions which can be separated using chemical methods.

Air contains 78% Nitrogen. So, it contributes more no. of moles to partial pressure than any other gas in the atmosphere. So, it has the highest partial pressure. 

The compound compound $ He$ is chemically unreactive (inert) and do not forms compound under normal reaction conditions.$He _2$ does not exist.

A greenhouse gas that absorbs energy and maintains earth's temperature is carbon dioxide.

The most abundant gas in the Earth's atmosphere is nitrogen, which accounts for about 78% of the mass of dry air. 

In desert areas, water vapour content is low because deserts are hot areas as there is a lack of water and if there is lack of water than there is lack of water vapour.

Evaporation of water in shade is slower, as the sun's heat increases the energy of water molecules, and they start moving faster, eventually leading to evaporation when the energy is enough to convert into a gas.

The two forms of oxygen found in the atmosphere are