List out the uses of nitrogen.
Important Points to Remember in Chapter -1 - Air from Tamil Nadu Board Standard Eight Science Solutions
1. Air
Air is defined as an invisible mixture of gases.
2. Oxygen
(i) Oxygen exists in nature as silicates, carbonates, oxides and water. It also exists in free state as part of air in the atmosphere.
(ii) Oxygen is a colourless and odourless gas, it dissolves sparingly in water, it is denser than air.
3. Chemical properties of oxygen
Metals like magnesium, iron and sodium burn in oxygen and give basic oxides.
4. Nitrogen
Though nitrogen is inactive at ordinary condition, it combines with many elements at high temperature and pressure or in the presence of catalyst.
5. Biological Fixation of Nitrogen
Bacteria convert atmospheric nitrogen directly into soluble nitrogen compounds.
6. Carbon dioxide
(i) Carbon dioxide cannot exist as a liquid at atmospheric pressure. It occurs as carbonates in nature.
(ii) Carbon dioxide is acidic in nature and turns lime water milky. It is used in fire extinguisher.
7. Greenhouse effect and Global Warming
(i) Global warming refers to an average increase in the temperature of the atmosphere or simply it is the warming of the earth.
(ii) The greenhouse gases are carbon dioxide, methane, nitrous oxide, chlorofluorocarbons, etc.
