water is the most essential chemical substance for life on earth. It has 2 Hydrogen atoms and 1 oxygen atom. It can take the shape of a container and can flow freely. It's particles are bound quite loosely. It exists in three states; a solid state, which is ice, a gaseous state, which is vapour, and it's common, liquid state. It covers 71% of the world's surface. Water can dissolve at least tiny ammounts of many substances. Unusually, ice is lighter than water so its solid floats on the liquid.