4.1.7 (HL)—Water properties

Water’s polarity, heat capacity, transparency, density behaviour and gas solubility create conditions for transport and life.

Polarity supports cohesion, adhesion and solvent action; transparency lets light enter; high specific heat capacity buffers temperature. Freshwater is densest near 4°C. At the same pressure, cooler water generally holds more oxygen and carbon dioxide, while at the same temperature a higher gas partial pressure increases equilibrium solubility.

Ice floats and insulates liquid water below, allowing aquatic life to persist through winter.

Cohesion holds water molecules together, while adhesion attracts water to other substances; together they support capillary movement.

A property matters through a mechanism; do not list ‘polarity’ without saying what it enables.