Intro
Air is found everywhere on Earth. The Earth is surrounded by a envelope of air. this air extends up to 200km in space. We are living at the bottom of the ocean air. |
Earth is surrounded by envelope of air means that the air covers the Earth. we are living at the bottom of the ocean air means we live at the lowest point of ocean where gasses are present. |
The atmosphere contains 78.3% Nitrogen, 20.9% Oxygen, and 1% other gasses and water vapour. |
Other gasses can include, carbon dioxide, noble gasses, ozone etc. |
Noble gasses can include, Helium, neon, argon, krypton, xenon and radon. |
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Water vapour
Water vapour is different from places to places. Arid regions have less water vapour compared to wetlands. In addition to water vapour there are some impurities such as Dust particles, carbon particles, Carbon monoxide, Nitrogen dioxide, Sulphur dioxide and **Chlorofluorocarbons ( CFC'S) |
So Arid regions are regions with very little water. impurities mean unwanted dust particles. |
Formula
Phosphorus + oxygen → Phosphorus pentoxide |
Phosphorus pentoxide + water → Phosphoric acid |
Tip: In any branch of science we write '=' as '→' |
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INVS 5.1 To show the presence of o2 and n2 in air
Materials: Test tube ( 8cm), graph paper (5cm), pea sized phosphorus, cotton wool plug, Beaker and water. |
Take a test tube 8cm long and fix it along a side of graph paper. in the tube place a pea sized phospohorus. over there also fix a cotton wool plug. invert ( put ) the test tube into the beaker and pour what it in till level 0. Now if you leave it undisturbed and untouched for a hour you will notice that the water level has risen up. why does this happen? |
This happens because the air present in the air slowly reacts with phosphorus to form phosphorus pentoxide gas. As the volume of oxygen is completely removed by phosphorus, therefore the pressure of air in the test tube falls and to make up for this loss air from outside forces the water up. |
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