Water and Life - Chapter 3

The four emergent properties of water

Cohesive behavior

Ability to moderate temperature

Expansion upon freezing

Versatility as a solvent

Cohesive behavior

Cohesion holds molecules together whilst adhesion holds those molecules to other substances

Ability to moderate temperature

Water can absorb and release its heat by changing its own temperature.

- Heat is absorbed when hydrogen bonds break
- Heat is released when hydrogen bonds form

Expansion upon freezing

Water molecules are closer together than ice molecules, so the water is more dense

Versatility as a solvent

A Solvent (water) can dissolve ionic substances and polar covalent compounds

Anything can dissolves in water if they have ionic and polar regions

Specific heat of water

1 cal/(g*c)

Specific heat is the amount of heat that must be absorbed or lost for a substance that weighs 1g to change its temperature by 1°C

Solute

A substance that is dissolved in a solution.

Solvent

A liquid substance capable of dissolving other substances.

Acids

Compounds that form hydrogen ions when dissolved in water

Bases

Compounds that reduce the concentration of hydrogen ions in a solution.

The pH scale

Ranges from 0 to 14 measuring the unit of hydrogen.

The lower the number on the scale, the higher the concentration of hydrogen (more acidic).

Buffers

minimize changes in concentrations of H+ and O H− in a solution