| A | B |
| acid | substance that increases the hydrogen ion concentration of a solution |
| acid precipitation | Rain, snow, or fog that is more acidic than pH 5.6. |
| adhesion | attraction between different kinds of molecules |
| aqueous solution | solution in which water is the solvent |
| base | substance that reduces the hydrogen ion concentration of a solution |
| buffer | substance that consists of acid and base forms in a solution and that minimizes changes in pH |
| calorie (cal) | amount of heat energy required to raise the temperature of 1 g of water by 1°C |
| Celsius scale | measures the freezing point of water at 0°C and the boiling point of water at 100°C |
| cohesion | binding together of like molecules, often by hydrogen bonds |
| colloid | mixture made up of a liquid and particles that (because of their large size) remain suspended in that liquid |
| evaporative cooling | property of a liquid whereby the surface becomes cooler during evaporation, owing to a loss of highly kinetic molecules to the gaseous state |
| heat | total amount of kinetic energy due to molecular motion in a body of matter |
| heat of vaporization | quantity of heat a liquid must absorb for 1 g of it to be converted from the liquid to the gaseous state |
| hydration shell | sphere of water molecules around each dissolved ion |
| hydrogen ion | single proton with a charge of +1 |
| hydrophilic | Having an affinity for water |
| hydrophobic | Having an aversion to water; tending to coalesce and form droplets in water |
| hydroxide ion | water molecule that has lost a proton |
| joule (J) | unit of energy: 1 J = 0.239 cal; 1 cal = 4.184 J |
| kilocalorie (kcal) | thousand calories |
| kinetic energy | energy of motion, which is directly related to the speed of that motion |
| molarity | common measure of solute concentration, referring to the number of moles of solute per liter of solution |
| mole (mol) | number of grams of a substance that equals its molecular weight in daltons and contains Avogadro’s number of molecules |
| molecular mass | sum of the masses of all the atoms in a molecule |
| pH | measure of hydrogen ion concentration equal to –log [H+] |
| polar molecule | molecule (such as water) with opposite charges on opposite sides |
| solute | substance that is dissolved in a solution |
| solution | liquid that is a homogeneous mixture of two or more substances |
| solvent | dissolving agent of a solution |
| specific heat | amount of heat that must be absorbed or lost for 1g of a substance to change its temperature by 1°C |
| surface tension | measure of how difficult it is to stretch or break the surface of a liquid |
| temperature | measure of the intensity of heat in degrees, reflecting the average kinetic energy of the molecules |