There many types of gases in nature. Of them some are natural and others are man made. These include
- Carbon dioxide
- Methane etc.
Definition of Gas
Gas is a matter whose molecules are bound by week forces of attraction such that they are widely separated from each other. Due to this, they are invisible and also without specific shape.
Since, any form of volatile matter is called a gas there are many others as well besides above.
Types of gases
There are basically two types as
- Natural gases (most common gases)
- Artificial gases.
The natural gases are present in nature spontaneously. These include common gases which are easily available through the air. While the artificial gases are obtained by a man from some chemical reactions.
The natural gases are again of two types as
- Elemental gases: These are the gases formed along with matter on earth and other planets. These gases are made of single element atoms. Examples of gases include Hydrogen (H2), oxygen (O2), nitrogen (N2), noble gases are the gases in the atmosphere.While Chlorine (Cl2), Fluorine (F2) are present in combination substances. Further, noble gases like helium, argon, kyrpton, radan, neon are monoatomic elements which mean they exist as individual atoms.
- Compound gases: These are also gases formed in nature out of biochemical processes. Chemically, these are combinations of two or more elements. They are formed by the combination of carbon, oxygen, nitrogen, hydrogen, nitrogen. Ex: carbon-dioxide (CO2), methane (CH4), sulfur dioxide (SO2), ammonia (NH3), etc.
These gases are present even before life existed on earth. So they are not harmful to nature as long as their concentration in the air ratio’s is not disturbed a lot.
The artificial gases are those which are synthesized by chemical reactions. They are made of many elements besides those listed above. They are also called as industrial gases.
These artificial gases include chlorofluorocarbons, anesthetics, sterilizing agents, etc. They are prepared by synthetic means for human use.
These are meant for special needs of man but are not useful to nature. In turn, some of them are harmful to nature. Chlorofluorocarbons used in refrigerators cause harm to the ozone layer. This ozone layer protects us from the harmful UV rays of the sun rays from reaching the ground. Hence their use in refrigerators is discontinued.
Also, there are acidic gases ex: Hydrochloric acid (HCl), Hydrofluoric acid (HF). Since they are volatile, they are used as a mixture of water. They have very low pH like 1.
Basic gases have pH more than 7. Ex: Ammonia (NH3).
Green House gases: These are the gases which enhance the earths temperature. These gases include carbondioxide, methanen nitrous oxide etc. They lead to greenhouse effect where in the surface of earth is kept warm. If the concentration of these gases increases, it can lead to global warming.
Thus we can understand that these gases are useful and also can be harmful to man.
Uses of Gases
list of common gases and their uses.
|Name of Gas||Its Uses|
|Oxygen||Respiratory support, Welding, Sterilzer|
|Carbon Dioxide||Refrigerant, Anti-explosive in combination with other gases,|
|Nitrogen||Liquid nitrogen for cold storage, For oxygen free environment, In respiratory support in health care.|
|Neon, Argon, Xenon||In electric bulbs and tubes|
|N2O (nitrous oxide)||Anesthetic in dental surgery|
|Sulfur dioxide||To preserve fruits, Wine making|
In medicine: gases are used in healthcare for respiration and anesthesia.
To aid respiration: In the case of respiratory insufficiency, oxygen therapy is given to sustain life. Respiratory insufficiency is a condition of lungs with the inability to expand and contract. Due to this, they cannot take sufficient oxygen from the air spontaneously. This Respiratory insufficiency occurs in diseases like COPD and pneumonia. Here oxygen in combination with normal air, nitrogen or even carbon dioxide is administered. Oxygen therapy helps the old age people and also those with brain and spinal cord damage to recover from asphyxia.
Also in tissue culture procedures, where tissue or cell is grown outside the body gases are supplied. For this especially oxygen in combination with nitrogen is suitable.
For anesthesia: Gases like halothane, enflurane, ether, chloroform are used to make the person lose consciousness. This loss of consciousness for desired time is called anesthesia. It is especially important during operations, surgery and even c-section delivery. The specialty in their use is, due to being gases, breath easily inhales them. The onset of anesthesia is very fast. Breath can also exhale the gas molecules so; even the recovery is fast. Since the induction and recovery are fast, these gaseous anesthetics find regular use in medicine.
For chemical analysis: Gases find their use even in the qualitative and quantitative analysis of compounds.
Materials used in drug manufacture, nutrition, and research are analyzed. In gas chromatography nitrogen is used as a carrier gas. While in flame photometry gases like hydrogen, argon is used as they help in the ignition of the samples.
For fuel: For domestic cooking, natural gas is widely used. The gas produces a blue color flame of high temperature. Besides this flame also does not form black suit and smoke, unlike tradition fuels.
Also gases like oxygen, acetylene are used in metal welding, called gas welding.
Even for automobiles, there is research going on for the use of hydrogen as fuel.
Similarly, Methane a biomolecule obtained from biomass is used to generate electricity
For lights & lamps: Most of the lamps made have noble gases. The gases helium, xenon are commonly used in the lamp helps to prevent damage to the electrodes in the bulb due to high-velocity ions. These ions slow down the velocity of ions and thereby enhancing the lifespan of the filament in the tubes and bulbs.
For refrigerator (cooling): In refrigerators and air conditioners, gases like carbon dioxide, ammonia, chlorofluorocarbons, sulfur dioxide are used for cooling. These gases take the heat from within and release it out by condensing to liquid. They then convert to gas by taking the internal heat. Thus they convert from the liquid phase to gas phases alternatively. This way they can aid in cooling of the compartments in a fridge and also in air conditioners. They are used widely in storage, pharmaceutical industries, cars and other automobiles.
For Cold transport: Liquid gases are used to transfer thermosensitive substances. Liquid nitrogen and solid carbon dioxide have very low temperatures. Liquid nitrogen has a temperature of -196° Celsius, while solid carbon dioxide has a temperature of -78.5° Celsius.This low temperature is suitable to keep the substances in a frozen state in a pack for a long time. Hence these are widely used in the transfer of food stuff, biological tissue samples, microbes, etc..
For Sterilization: Ethylene oxide is one of the gases used in sterilization methods. These gases are toxic and can kill all the possible microbes when exposed. Ethylene oxide is also highly inflammable, and hence, it is used in combination with carbon dioxide to prevent chances of an explosion. The microbes get killed when exposed to this gas. This sterilization keeps the whole area sterile. Gaseous sterilization is especially useful in drug, food carrying containers. Once the drugs or food packets arranged in containers for transport, these toxic gases are allowed to pass through. These gases move into every corner of the container even in between gaps and helps ineffective sterilization.
In Research: gases are also used in research for experimental purposes. Nitrogen is used to create a non-oxygen atmosphere. Also, it is used to remove oxygen from solutions to study oxidation levels. In plant tissue culture, to provide sterile oxygen supply to the growing plant tissue.
For purification of substances: When a solid or liquid is impure, it can be purified by converting it into gas and then reconverting to the prior form. Even sublimation process can purify the solids like naphthalene. If the material is heat sensitive, it can be boiled at low temperature under vacuum to convert into gas and then the gas is re-condensed to the original state of solid or liquid. Thus converting a substance into gas helps in its purification.
In agriculture: Nitrogen is an important element used as fertilizer. It is converted from air into ammonia and fixed in the soil by some bacteria. This ammonia acts as a fertilizer to the crop. When the crop is destroyed, the gas is again returned back to the atmosphere.
Similarly, in swimming pools and public water supplies, bleaching powder is used to kill disease-causing microbes. This bleaching powder i.e. Ca (ClO)2 is a strong oxidizer. When mixed with water, it releases chlorine and oxygen gas atoms (O) which are highly toxic to microbes. These gas atoms kill the microbes and hence sanitize fresh water.
Also, room freshers, insect repellents which we use regularly emit volatile forms of gases.
Properties of Gas
- Due to weak forces of attraction in between molecules, gases have less density.
- They are easily compressible.
- When compressed or during expansion, they exert pressure on all directions simultaneously.
- When one or more gases are mixed, they get mixed up homogeneously.