Water: Properties, Distribution, and Uses

Water is highly unusual because it expands upon freezing. This occurs because hydrogen bonds form a crystalline lattice structure in ice that keeps the molecules further apart than they are in liquid water.

Water vapor is the gaseous state of water. Because it is a gas, it is primarily found suspended in the Earth's atmosphere.

A phase change from liquid to gas does not alter the chemical identity of a substance. Therefore, water vapor has the exact same molecular formula as liquid water, which is H2O.

The vast majority of Earth's water is found in the oceans, which are composed of liquid water. Only a small fraction exists as solid ice in glaciers or as water vapor in the atmosphere.

Oxygen is highly electronegative and pulls shared electrons closer to itself, acquiring a partial negative charge. This leaves the hydrogen atoms with a partial positive charge, creating the molecule's polar nature.

Water is a polar molecule because of the unequal sharing of electrons between the highly electronegative oxygen atom and the hydrogen atoms. This creates a partial negative charge near the oxygen and partial positive charges near the hydrogens.

Agriculture is the largest consumer of freshwater globally, accounting for approximately 70% of human water use. In contrast, industrial activities account for only about 20% of global water use.

Power stations generate massive amounts of waste heat and require water for cooling purposes, not for heating. Generating energy, extracting minerals, and cleaning products are all standard industrial uses of water.

Globally, industry accounts for roughly 20% of human water use, while agriculture accounts for about 70%. Therefore, the statement that 50% of human use is due to industry is incorrect.

Water is one of the most powerful agents of erosion and weathering on Earth. Over long periods of geological time, flowing water can carve massive canyons, wear down mountains, and completely reshape landscapes.

Water drives weather patterns on Earth through evaporation, condensation, and precipitation. The movement of water vapor and liquid water in the atmosphere is directly responsible for clouds, rain, snow, and humidity.

Of the roughly 3% of Earth's water that is fresh, about 70% to 75% is locked up in solid form as glaciers and ice caps, making it largely inaccessible for direct human use or agriculture.

Approximately 97% of Earth's water is salty ocean water. Only about 3% is freshwater, and most of that is locked up in glaciers and ice caps.

Water covers approximately 71% of the Earth's surface, with the vast majority of this coverage consisting of the global oceans.