What is the chemical formula for water?

The chemical formula for water is H2O, which indicates that each molecule of water is composed of two hydrogen atoms bonded to one oxygen atom. This simple molecular structure is fundamental to the nature of water, making it a crucial substance for life on Earth. The arrangement of these atoms creates unique properties for water, such as its ability to act as a solvent, its high specific heat, and its solid form being less dense than its liquid form. These properties are vital for various biological and ecological processes.

The other formulas represent different compounds: CO2 is carbon dioxide, which consists of one carbon atom and two oxygen atoms; NaCl is sodium chloride, commonly known as table salt, consisting of sodium and chlorine; O2 represents molecular oxygen, which is essential for respiration in many living organisms. Each of these compounds serves different functions and has distinct characteristics compared to water.