BIOL 110 - Chapter 3 - Water and Life

Cohesion

attraction between water molecules

Adhesion

attraction between different substances

Surface Tension

a measure of how hard it is to break the surface of a liquid

Kinetic Energy

energy of motion

Heat

measure of the total amount of kinetic energy due to molecular motion

Temperature

measures the intensity of heat due to the average kinetic energy of molecules

Celsius Scale

measure of temperature using Celsius degrees (C)

Calorie

amount of heat required to raise the temperature of 1 g of water by 1 C

Specific Heat

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

Evaporation

transformation of a substance from liquid to gas

Heat of Vaporization

the heat a liquid must absorb for 1g to be converted to gas

Evaporative Cooling

as a liquid evaporates, its remaining surface cools; helps stabilize temperatures in organisms and bodies of water

Solution

a liquid that is a homogenous mixture of substances

Solvent

dissolving agent of a solution

Solute

the substance that is dissolved

Aqueous Solution

water is a solvent

Hydration Shell

when an ionic compound is dissolved in water, each ion is surrounded by a sphere of water molecules

Hydrophilic

a substance that has an affinity for water

Hydrophobic

a substance that does not have an affinity for water

Molecular Mass

sum of all masses of atoms of all atoms in a molecule

Molarity

number of moles of solute / liter of solution

Dynamic Equilibrium

molecules dissociate at the same rate at which they are being reformed

Acid

any substance that increases the H⁺ concentration of a solution (acidic solutions have pH values less than 7)

Base

any substance that reduces the H⁺ concentration of a solution (basic solutions have pH values greater than 7)

pH

expressing the acidity or alkalinity of a solution (pH = -log [H⁺])

Buffers

substances that minimize changes in concentrations of H⁺ and OH^- in a solution