Chemistry: Environmental Systems - Earth Systems (Atmosphere, Hydrosphere, Lithosphere, and Biosphere)

The Atmosphere is the layer of gases surrounding Earth, primarily composed of $78\%$ Nitrogen ($N_2$), $21\%$ Oxygen ($O_2$), and $1\%$ Argon ($Ar$), Carbon Dioxide ($CO_2$), and other trace gases.

The Hydrosphere encompasses all water on Earth in liquid, solid, and gaseous phases. The water molecule is represented as $H_2O$. Ocean water contains dissolved salts, primarily Sodium Chloride ($NaCl$).

The Lithosphere is the solid, outer part of the Earth, including the crust and the brittle upper portion of the mantle. It is rich in elements such as Silicon ($Si$), Oxygen ($O$), Aluminum ($Al$), and Iron ($Fe$).

The Biosphere is the zone of Earth where life exists. It interacts with other spheres through biogeochemical cycles, such as the Carbon Cycle and the Nitrogen Cycle.

The Greenhouse Effect is a natural process where gases like $CO_2$, $CH_4$ (Methane), and $N_2O$ (Nitrous Oxide) trap heat in the atmosphere, maintaining Earth's temperature.

Acid Rain occurs when compounds like Sulfur Dioxide ($SO_2$) and Nitrogen Oxides ($NO_x$) react with water ($H_2O$) and Oxygen ($O_2$) in the atmosphere to form mild acids.

Photosynthesis is the process by which plants in the biosphere convert solar energy into chemical energy, using $CO_2$ and $H_2O$ to produce Glucose ($C_6H_{12}O_6$).