Chemistry PP #11

Vaporization

the process by which a solid or liquid changes to a gas

Boiling

vaporization in which the liquid particles change into a gas throughout the entire liquid

Evaporation

vaporization in which particles escape from the surface of a non-boiling liquid and enter the gaseous state. Occurs only on the liquid’s surface but at any temperature.

Normal Boiling Point

the temperature at which a liquid boils at one atmosphere of pressure (760mm Hg)

Sublimation

process by which a solid turns directly to a gas without passing throughout the liquid state

Deposition

process by which a gas turns directly into a solid without passing through the liquid state

Heat of vaporization/condensation

amount of heat required to vaporize or condense one gram of a liquid at its boiling point

Heat of fusion/crystallization

the amount of heat required to melt or freeze one gram of solid at its melting point

Pressure

the force applied divided by the surface area of application (P = F/A) (pascal)

atmospheric pressure

the pressure exerted by the atmosphere around us which is also called air pressure of barometric pressure

normal atmospheric pressure/air pressure

the average pressure at sea-level, which equal to the pressure that will support a column of mercury 760 mm tall; also called one atmosphere or standard pressure

standard temperature and pressure

the conditions most often used in chemistry to study or test a chemical

vapor pressure

the pressure of the vapor in contact with its liquid in a sealed container

equilibrium vapor pressure

an indication of a liquid’s evaporation rate. It relates to the tendency of particles to escape from the liquid. A substance with a high vapor pressure at normal temperatures is often referred to as volatile. Many organic compounds have high numbers of this and are called volatile organic compounds.

phase diagram

a common way to represent the various phases of a substance and the conditions under which each phase exists

triple point

at this temperature and pressure, three phases can coexist at equilibrium

critical point

at a temperature above critical temperature, and a pressure above the critical pressure, it is no longer possible to distinguish between the gas and liquid phases

density

a measure of the concentration of matter

solution concentration

the amount of substance in a given volume or mass of the mixture. The units are moles per volume.

Molarity

the number of moles of solute dissolved in 1 liter of solution

equilibrium

a balance of two opposing forces occurring at equal rates in the same closed system

physical equilibrium

can occur in a closed container of any water solution. The opposing forces or processes are evaporation and condensation

reversible reactions

reactions that can run in both directions

equilibrium constant expression

also called law of mass action; is a ratio of molar concentrations of products divided by reactants; used to determine relative concentrations of reactants and products for a reaction at equilibrium

Le Chatelier’s Principle

if an external stress is applied to a system at equilibrium, the position of the equilibrium will shift in a direction that reduces this stress