CHEMISTRY [2 Mark Question Answer]

Carbon dioxide and water in the presence of sunlight and chlorophyll is changed into carbohydrates and oxygen is released out.

Ozone is present in the upper layer of the atmosphere called the stratosphere. It protects the earth from harmful ultraviolet rays of the sun.
Some air pollutants like chlorofluorocarbon (CFC) react with ozone present in the atmosphere. These pollutants reduce the density of the air. The ultra-violet rays from the sun reach directly on the earth which affects human health, causing skin diseases and cancer and also increase the earth’s temperature.

For artificial respiration mountaineers carry oxygen cylinders as at high altitudes, the air is thin and breathing becomes difficult. Also divers carry oxygen cylinder for artificial respiration as there is less oxygen dissolved in water (less dense) and breathing becomes difficult.

Photosynthesis: Process of producing food by green plants taking CO2 from the air, water from the soil by roots, and in the presence of sunlight and chlorophyll is called photosynthesis.

Respiration: Respiration is a chemical process that takes place in all living beings (slow in plants). In this process, oxygen present in inhaled air reacts with the digested food material in the body. This results in the release of energy, carbon dioxide, and water.
Sugar + Oxygen → CO2 + Water + Energy.

Water vapour: Water vapors present in air provide moisture for both plants and animals. It also helps in predicting climatic conditions of a particular area as its amount varies from place to place and from time to time.

Carbon dioxide: Carbon dioxide is used by plants to prepare their food by photosynthesis. Dry ice (solid carbon - dioxide) is used as a refrigerant. Carbon dioxide is used to prepare fizzy drinks like soda water.

Nitrogen: Present in air gets fixed up in the soil as nitrates used by plants for their growth and for the formation of protein an important nutrient for animals. It is used to make fertilizers and various nitrogenous products.

Oxygen: For respiration and breathing no life is possible without oxygen. Oxygen is the most vital component which is responsible for two most important processes,

1. Respiration and
2. Combustion.

Water has a lot of air dissolved on it. This is what allows breathing to fishes and other aquatic beings. The solubility of gases decreases when the temperature is raised, and that is why the dissolved air bubbles out from the water.

Without an atmosphere, life would not be possible as the atmosphere protects us from harmful gases. We could not live without air present in the atmosphere. In the absence of the atmosphere, the earth would get so cold at night that we would not be able to survive. No CO2 and N2 for plants without atmosphere.

Nitrogen is utilised by plants for their growth and development. Free nitrogen of the air is converted to nitrogen compounds which are absorbed by the plants and converted to plant proteins. In the absence of nitrogen no plants will be survived on the earth.