Water Structure and Molecular Properties

Vocabulary flashcards covering water’s structure, polarity, hydrogen bonding, and key properties like cohesion, adhesion, surface tension, and thermal properties.

Water (H2O)

A molecule made of two hydrogen atoms and one oxygen atom; bonds are polar covalent, creating a polar molecule with a slight positive charge on the hydrogen side and a slight negative charge on the oxygen side.

Polar covalent bond

A covalent bond where electrons are shared unevenly between atoms, producing partial charges.

Polarity

A property of a molecule with two opposite charges at different ends, enabling intermolecular attractions.

Hydrogen bond

An intermolecular attraction between a hydrogen atom on one molecule and a highly electronegative atom (usually oxygen) on another molecule; not a true chemical bond.

Intermolecular forces

Forces that occur between molecules, such as hydrogen bonds, influencing properties but acting between separate molecules.

Cohesion

Water molecules sticking to each other due to hydrogen bonding, contributing to surface tension.

Adhesion

Water molecules sticking to polar surfaces, enabling phenomena like capillary action in plants.

Surface tension

The cohesive force at the surface of water that resists external penetration, allowing droplets to form.

Capillary action

Movement of water in narrow tubes against gravity, driven by adhesion to surfaces and cohesion between water molecules (e.g., in xylem).

Specific heat capacity (water)

The amount of energy required to raise the temperature of water; water has a high specific heat, promoting temperature stability.

Heat of vaporization

The energy required to convert liquid water to gas; water has a high heat of vaporization, enabling cooling through evaporation.

Evaporative cooling

Cooling achieved when water evaporates from a surface (e.g., sweating, panting), removing heat from the body.

Temperature regulation in organisms

Water’s high specific heat and high heat of vaporization help stabilize body temperatures, aiding temperature regulation.