Question

Define greenhouse gas and also give an example.

Answer 1

Hint: The main greenhouse gas is a saturated hydrocarbon; it is found in almost 1750 ppb, it is also found in the guts of ruminant animals. The second compound which is found in almost 280 ppm in the atmosphere, is inorganic and plays a great role in photosynthesis.

Complete answer:
A greenhouse gas is a gas that absorbs and emits radiant energy within the thermal infrared range, causing the greenhouse effect.
The two main gases that are responsible for the greenhouse effect, the first one being methane, are present in most quantities in the atmosphere. The second is carbon dioxide, the amount of carbon dioxide is increasing in the atmosphere due to the increase in the burning of fossil fuels.

Additional information:
1. There are four main gases responsible for greenhouse gases: Methane, carbon dioxide, chloro-fluoro carbons, and nitrous oxide.
2. Greenhouse effect is a naturally occurring phenomenon that is increasing the earth's surface temperature.
3. Fourier was the scientist who first defined the phenomenon of the greenhouse effect in 1827.
4. Without the greenhouse effect the temperature of the earth's surface would have been -18 degrees celsius.
5. The term “greenhouse” is inspired by a small setup of a small glasshouse which is used during the development of plants, especially during winters.
6. In the greenhouse, the glass panel allows the heat from an external source to come in but the heat cannot escape out of the glass. This assists the plants to grow efficiently.

So, the correct answer is ‘methane and carbon dioxide’.

Note:
Nitrous oxide is present in the atmosphere with 316 ppb. One of the major sources that cause an increase in the level is agricultural and biomass burning.
Chloro fluoro carbons are present in the atmosphere at 282 ppb. Major sources of these compounds are leakages of electronics like refrigerators and air conditioners.