Campbell Biology Chapter 3

polar molecule

molecule with an unequal distribution of charge, resulting in the molecule having a positive end and a negative end

4 emergent properties of water

1. Cohesion

2. Temperature Moderation

3. Expands upon freezing

4. Versatile as solvent

cohesion

tendency of molecules of the same kind to stick to one another

adhesion

attraction between molecules of different substances; in plants, attraction between unlike molecules

surface tension

a measure of how difficult it is to stretch or break the surface of a liquid

moderation of temperature by water

-absorbs heat from air that is warmer and releasing the stored heat to the air that is cooler.

-high specific heat/ high heat of vaporization

kinetic energy

energy of motion

heat

a form of energy that is transferred by a difference in temperature

temperature

a measure of the intensity of heat in degrees, reflecting the average kinetic energy of the molecules, regardless of volume.

calorie

unit of heat defined as the quantity of heat required to raise the temperature of 1 gram of water by 1 degree centigrade at atmospheric pressure

joule

si unit of energy

specific heat

the heat required to raise the temperature of one gram of a substance one degree centigrade

evaporation

the process by which water changes from liquid form to an atmospheric gas

heat of evaporation

the quantity of heat a liquid must absorb for 1 g of it to be converted from the liquid to the gaseous state

evaporative cooling

Property of a liquid whereby the surface becomes cooler during evaporation because of a loss if highly kinetic molecules to the gaseous state

solution

a homogeneous mixture of two or more substances

solvent

a liquid substance capable of dissolving other substances

solute

Substance that is dissolved in a solvent to make a solution

aqueous solution

A solution in which water is the solvent

hydration shell

The sphere of water molecules around each dissolved ion

hydrophilic

having a strong affinity for water

colloid

a mixture containing small, undissolved particles that do not settle out

hydrophobic

lacking affinity for water

molecular mass

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

mole

6.02 X 10^23

molarity

the number of moles of solute per liter of solution

hydronium ion

H₃O⁺

acid

a substance that increases the hydrogen ion concentration of a solution

base

a substance that reduces the hydrogen ion concentration of a solution

pH

a value that indicated the acidity or alkalinity of a solution on a scale of 0-14, based on the proportion of H+ ions.

buffer

substance that maintains a fairly constant pH in a solution by accepting H+ ions when their levels rise and donating H+ ions when their levels fall

ocean acidification

When CO2 dissolves in seawater, it reacts with water to form carbonic acid, which lowers ocean PH