Concise Selina Solutions for Class 7 Chemistry Chapter 7 Air and Atmosphere


The atmosphere of Earth is the layer of gases, commonly known as Air, retained by Earth's gravity, surrounding the planet Earth and forming its planetary atmosphere. Air is mostly gas. It's a mixture of different gases. The Air in Earth's atmosphere is made up of approximately 78 per cent nitrogen and 21 per cent oxygen. Air also has small amounts of lots of other gases, such as carbon dioxide, neon, and hydrogen. The Air is the gas mixture that forms the Earth's atmosphere, which remains around our planet thanks to the attraction of the force of gravity. The atmosphere is the Earth's gaseous region, the outermost and least dense region of the planet. The atmosphere is an essential part of what makes Earth liveable. It blocks some of the Sun's dangerous rays from reaching Earth. It traps heat, making Earth a comfortable temperature. And the oxygen within our atmosphere is essential for life.