Properties of Water

Vocabulary flashcards reviewing the key chemical and biological properties of water, including hydrogen bonding, adhesion, cohesion, high specific heat, and evaporative cooling.

Water Molecule

A polar molecule with an extended V-shape that covers approximately $\frac{3}{4}$ of the Earth's surface and is essential to all known life.

Electronegativity in Water

The tendency of oxygen to strongly pull shared electrons toward itself, resulting in a slightly negative charge on the oxygen atom and slightly positive charges on the hydrogen atoms.

Hydrogen Bond

The weak bond formed between the slightly positive hydrogen atom of one water molecule and the slightly negative oxygen atom of another water molecule.

Xylem

Vascular tubes within certain types of plants, such as trees, that transport water upward against gravity.

Adhesion

The ability of water molecules to cling to other surfaces, such as the walls of the xylem, helping water move upward against the force of gravity.

Cohesion

The property whereby water molecules bind to one another via hydrogen bonds, pulling consecutive molecules upward like beads on a string as evaporation occurs.

Surface Tension

A measure of how difficult it is to stretch or break the surface of a liquid; in water, it is produced by cohesion and allows organisms such as water striders, spiders, and certain reptiles and birds to walk on water.

Solvent

A dissolving agent; water functions as a powerful solvent that dissolves polar molecules and ionic compounds, enabling vital biological processes such as kidney function.

Expansion upon Freezing

The property of water to expand and become less dense as a solid than as a liquid because hydrogen bonds lock molecules into an open lattice, allowing ice to float and insulate aquatic organisms underneath.

Specific Heat

The measure of the amount of heat that must be absorbed or lost for $1\text{ gram}$ of a substance to alter its temperature by $1^\circ\text{C}$.

Evaporative Cooling

The process by which the fastest-moving water molecules carrying the greatest thermal energy escape into the gas phase, removing heat from plant surfaces and animal bodies to protect vital enzymes from overheating.