Physical Chemistry

energy (1)

capacity to do work

work (1)

process of moving against an opposing force

thermodynamics (1)

study of heat, work, and energy changes during processes

open system (1)

exchange matter and energy

closed system (1)

exchange energy only

isolated system (1)

no exchange of matter or energy

standard enthalpy of formation (2)

the enthalpy change when forming 1 mol of substance in its standard state from its elements

standard reaction enthalpy (2)

the enthalpy change when 1 mol of substance reacts under standard conditions

standard enthalpy of combustion (2)

the enthalpy change for the complete combustion of a substance with oxygen, typically hydrocarbons

Hess’ law (2)

the net enthalpy change for a reaction equals the sum of enthalpy changes of individual steps

entropy (3)

a fundamental concept in thermodynamics relating to a disorder, often symbolized as S and associated with the number of microstates (disorder) corresponding to a thermodynamic system.

heat (3)

represents energy due to the random motion of molecules

reversibility (3)

a system can return to its original state with small changes in conditions without any net change in the surroundings.

stoichiometry (5)

study of the numbers of reactants and product molecules

rate of reaction (5)

number of moles of reaction per unit time

order of reaction (5)

the power to which the concentration is raised in the rate law

zero order (5)

rate is independent of concentration

pre-exponential factor (A) (6)

represents how frequently molecules collide in the proper orientation to react

activation energy (Ea) (6)

the minimum energy required for molecular collisions to result in a reaction

arrhenius law (6)

a formula that relates the rate constant of a reaction to the temperature and activation energy.

transition state theory (6)

the maximum energy required corresponds to the formation of an activated complex of the original reactants

catalyst (6)

accelerates reactions without being consumed in the process

half life (7)

time for concentration to decrease to half its initial value

equilibrium (8)

the rate of formation of products equals the rate of decomposition of reactants

dynamic chemical equilibrium (8)

a state where the concentrations of reactants and products remain constant over time as they are continuously formed and decomposed

chemical standard state (8)

typically defined as 1 mol dm^-3 concentrations

biological standard state (8)

maintains 1 mol dm^-3 & ph7 (with [H+] = 10^-7 mol dm^-3) and a temperature of 25°C.

reaction quotient (Q) (8)

provides a measure of the relative amounts of products and reactants at any point

monoprotic acid (10a)

acid containing one proton

diprotic acid (10a)

acid containing two protons

triprotic acid (10a)

acid containing three protons

Ka (10a)

acid dissociation constant, measures the strength of an acid

Kd (10a)

measure propensity (tendency) to dissociate reversibly, reciprocal of Ka. describes binding affinity of a ligand to a protein

acid (10b)

donates protons (H+)

base (10b)

accepts protons

strong acid (10b)

an ** that completely dissociates in solution, releasing all its protons. ionizes fully.

buffer (10b)

solution that maintain a constant pH when diluted or when acid/base

latent heat for melting (q) (11)

heat required to convert 1 mol of solid to liquid at melting point

latent heat for boiling (q) (11)

heat required to convert 1 mol of liquid to gas at boiling point

enthalpy of fusion (11)

energy required to convert 1 mol of solid (ice) to liquid at the melting point (0 C) = 6.01 kj mol-1enth

enthalpy of vaporization (11)

energy required to convert 1 mol of liquid (water) to gas (steam) at boiling point (100 C) = 40.7 kj mol-1

oxidation (12)

loss of electrons

reduction (12)

gain of electrons

redox reaction (12)

involves loss of electrons from one species and gain by another

reducing agent (12)

acts as an electron donor and is itself oxidized

oxidizing agent (12)

acts as an electron acceptor and is itself reduced

electrochemistry (12)

study of chemical processes that cause electrons to move

voltaic (galvanic) cell (12)

generates current spontaneously

electrolytic cell (12)

requires external voltage to drive a reaction

metal electrode (13)

composed of metal in contact with an ionic solution

redox electrode (13)

involves an inert metal in contact with a solution containing a species in two oxidation states

gas electrode (13)

consists of a gas in equilibrium with its ionic solution in the presence of an inert metal

insoluble salt electrode (13)

involves a metal (M) coated with an insoluble salt (MX) immersed in a solution containing X- ions

vertical bar I (13)

denotes a barrier (eg. Ag l AgCl )

double vertical bars ll (13)

represents connection, such as a salt bridge

anode (13)

left hand half cell

cathode (13)

right hand half cell

cell potential (E) (13)

the difference between the electrode potentials of the cathode and anode

zero current potential (13)

the maximum amount of non-expansion work (Wmax= deltaG)