Properties of Water – Biology A1.1

A set of question-and-answer flashcards reviewing the key physical and chemical properties of water discussed in the lecture notes.

What type of bond joins hydrogen and oxygen atoms within a water molecule?

A polar covalent bond.

When a solution is described as "aqueous," what does that mean?

Water is the solvent—substances are dissolved in water.

Why is the oxygen atom in water considered highly electronegative?

It attracts shared electrons more strongly, creating a partial negative charge and giving water its polarity.

What term describes the attraction between individual water molecules?

Cohesion.

How are water molecules able to be transported upward in a continuous column inside plant xylem vessels?

Cohesion (molecule-to-molecule attraction) maintains an unbroken column under tension.

Which property of water lets small insects such as water striders walk on its surface?

High surface tension.

Why is water itself considered an important habitat for countless organisms?

Its physical and chemical stability (e.g., high specific heat) creates a stable environment that supports life.

What term is used for water’s tendency to stick to other substances?

Adhesion.

Give a biological example of adhesion in action.

Water molecules adhere to plant cell walls in xylem, helping pull water upward.

What phenomenon, driven by both cohesion and adhesion, allows water to climb narrow tubes against gravity?

Capillary action.

Which property of water allows it to change temperature only slowly, therefore helping regulate environmental and body temperatures?

High specific heat capacity.

Which property of water makes sweating or transpiration an effective cooling mechanism?

High latent heat of vaporisation.

Compared with most other liquids, water has low viscosity. What does viscosity measure?

The thickness of a fluid and its resistance to flow (how much thrust is needed to move through it).

How have many aquatic animals adapted their body shape to lower resistance in water?

They have streamlined bodies to reduce drag.

Which characteristic of water enables organisms to float and supports the mass of large marine mammals like whales?

High buoyancy (due to water’s density).

Why is water often called the "universal solvent"?

Its polarity allows it to dissolve many ionic and polar substances.

What term describes molecules that readily interact with or dissolve in water due to their polarity or charge?

Hydrophilic.

What term describes molecules that repel or fail to mix with water?

Hydrophobic.