2.7 Water

Solvent

As a polar substance, water attracts ions and other polar molecules

Positive hydrogen ends of water are attracted to negative regions of solute molecule/ion

Negative oxygen end of water is attracted to positive regions of solute molecule/ion

Water molecules cluster around solute molecules/ions and separate them - dissolving

High specific heat capacity

Hydrogen bonds absorb lots of energy

Lots more energy needed for water temperature to be raised

Temperatures within cells/organisms and aquatic habitats are more stable than surrounding air

High latent heat of vaporisation

Hydrogen bonds absorb lots of energy

Lots of energy absorbed from surroundings when water molecule breaks free and becomes gas/evaporates, surrounding temperature decreases

Surrounding temperature further decreases because only highest energy water molecules break free, leaving lower energy molecules behind

Mammals sweat, evaporating water loses a lot of heat energy, cools down

Reactant (for hydrolysis, photosynthesis)

Cohesion/adhesion

Water molecules are pulled together (positive hydrogen end towards negative oxygen end of another molecule)

Surface tension at air-water boundary, water molecules held together and pulled inwards

Adhesion - water molecules held together on a surface, water-solid boundary

Low viscosity

Density

Less dense as solid than liquid

Molecules align themselves in regular lattice when solid

Orientation of hydrogen bonds spreads out water molecules