There are many types of gases in nature. Of them, some are natural, and others are manufactured. These include
- Carbon dioxide
- Carbon monoxide
- sulfur dioxide
- Nitrous oxide
- Methyl chloride
- Hydrogen chloride 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 a specific shape.
Since any form of volatile matter is called a gas, there are many others besides the above.
Types of gases
There are basically two types as
- Natural gases (most common gases)
- Artificial gases.
The gases you come across during your initial science classes are natural.
These include oxygen, nitrogen, hydrogen etc.
Of these natural gases, some are elemental, while others are compound based. Few of them are also synthetic and man-made.
The natural gases are present in abundance in nature and air
The natural gases are again of two types as
- These are the gases formed along with matter on earth and other planets.
- They are made of single element atoms.
- Examples are: Hydrogen (H2), oxygen (O2), nitrogen (N2), noble gases are gases in the atmosphere.
- At the same time, Chlorine (Cl2), Fluorine (F2) are present in combination with substances.
- Noble gases like helium (He), argon (Ar), krypton (Kr), radon (Rn), neon (Ne) are monoatomic elements, which mean they exist as individual atoms.
- These gases are 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, and sulfur.
- Ex: carbon-dioxide (CO2), methane (CH4), sulfur dioxide (SO2), ammonia (NH3), etc.
- Natural gases are present even before life existed on earth. So they are not harmful to nature as long as their concentration ratios are not disturbed.
- These gases are synthesized by man through chemical reactions for industrial use.
- They are made of many elements besides those listed above.
- Chlorofluorocarbons like R11, R12.
- Anesthetics like halothane, sevoflurane, desflurane, isoflurane.
- Microbial Sterilizing agents like diethyl ether
- These are not useful to nature and some of them are even harmful to nature.
- Chlorofluorocarbons used in refrigerators harm the ozone layer leading to its depletion. This ozone layer protects us from the harmful UV rays of the sun rays from reaching the ground.
These gases are chemically acidic in nature. They have a pH below 7, and some of them are quite strong acids.
Acid gases list
- Hydrochloric acid (HCl),
- Hydrofluoric acid (HF).
Since they are volatile, they are used as a mixture in water. They have a very low pH.
Contrary to acidic gases, these have a pH of more than 7.
Ex: Ammonia (NH3).
Green House gases
These are gases that enhance the earth’s temperature. These gases include carbon dioxide, methane, nitrous oxide, etc. They lead to the greenhouse effect, wherein the surface of the 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, Sterilizer|
|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)||Anaesthetic in dental surgery|
|Sulfur dioxide||To preserve fruits, Winemaking|
Gases are widely used in healthcare for respiration and anaesthesia.
To aid respiration
- In the case of respiratory insufficiency, oxygen therapy is given to sustain life. Respiratory insufficiency is a condition of the 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 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.
- Gases like halothane, enflurane, ether, chloroform are used to make the person lose consciousness.
- This loss of consciousness for the desired time is called anesthesia.
- It is especially important during operations, surgery, and even C-section delivery. The specialty is, they can be inhaled and the onset of anesthesia is very fast.
- Due to exhalation the recovery from anesthesia is fast too.
Since the induction and recovery are fast, these gaseous anaesthetics 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.
Other daily life activities
As fuel for cooking and other areas.
- 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 a black suit and smoke, unlike traditional fuels.
- 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 welding of metals.
Gases like oxygen, acetylene is used in metal welding, called gas welding.
For lights & lamps
- Most of the electric lamps we use 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 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 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 foodstuff, biological tissue samples, microbes, etc.
- Ethylene oxide is one of the gases used in microbial sterilization.
- These gases are toxic and kill all the possible microbes when exposed.
- Gaseous sterilization is especially useful for drug, food carrying containers.
- Once the drugs or food packets are arranged in containers for transport, these toxic gases are allowed to pass through.
- These gases move into every corner and gaps of the container and help ineffective sterilization.
- 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 and separation of substances
- When a solid or liquid is in impure state, it can be purified by converting it into another state.
- For example naphthalene is solid at room temperature and if it impure, it is converted to gas by the sublimation process.
- This gaseous form is re-cooled to solid in another container to obtain pure sample.
- Similarly, by distillation, we can obtain ion free water.
- 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.
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 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), that is 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 between molecules, gases have less density.
- They are easily compressible.
- When compressed or during expansion, they exert pressure in all directions simultaneously.
- When one or more gases are mixed, they get mixed up homogeneously.