Water Properties, Dissociation, and pH: Key Concepts for Biology

What is responsible for changing liquid to gas?

Kinetic energy, heat

Why does solid water (ice) float in liquid water?

Less dense, more open crystalline structure

What are the 4 properties of water?

1. High heat capacity 2. High heat of vaporization 3. Water is a solvent 4. Cohesion & adhesion

What is adhesion?

Water molecules are attracted to non-water molecules

What's the opposite of adhesion?

Cohesion

What is the process called when water 'climbs' by adhesion?

Capillary action

Which process maintains water droplet shape?

Cohesion

What occurs when atoms or groups of atoms break off from molecules and form ions?

Dissociation

What kind of bond is formed by NaCl in water?

Ionic bond

How will KCl dissociate in water?

The slightly negative regions of Oxygen will be attracted to K+; slightly positive regions of Hydrogen will be attracted to Cl-.

What is this called when ions are surrounded by water molecules?

Spheres of hydration

What kind of bond is formed by HCl in water?

Covalent bond

Is HCl polar or nonpolar? How do you know?

Polar; it has slightly positive and negative regions.

What do excess H+ ions mean?

High acidity, Low pH

What is ocean acidification?

A decrease in the pH of the ocean.

What is the range of the pH scale? What pH is neutral?

pH scale = 0-14; pH of 7 is neutral.

What is the difference between a base and a buffer?

A base reduces the H+ concentration, while a buffer reduces fluctuations in H+ concentrations.