Chemistry Unit 2 Key Definitions

An activation energy is the MINIMUM energy required for a particle to react.

A catalyst is a substance that alters the rate of a reaction BUT IS NOT USED UP in the reaction

Dynamic equilibrium is a situation in which the FORWARD AND BACKWARD REACTIONS ARE OCURRING AT THE SAME RATE.

Electrophillic addition occurs when an ALKENE is attacked by an electrophile eg. HBr

Elimination occurs when an OH ion is reacted with a HALOALKANE in a HOT ETHANOLIC mixture

Enthalpy change is a measure of HEAT ENERGY given out or took in at CONSTANT PRESSURE

Enthalpy diagrams plot ENERGY LEVELS of REACTANTS and PRODUCTS on a vertical scale

The fingerprint region is the area of an INFRA-RED SPECTRUM below 1500CM that is INDIVIDUAL TO EACH MOLECULE.

The Maxwell-boltzmann distribution shows the distribution of ENERGIES/SPEEDS of molecules in GAS/LIQUID

Mean Bond Enthalpy is the AVERAGE ENTHALPY required to break a particular bond.

Molecular ion in MASS SPECTROMETRY is a molecule that had been IONISED but not BROKEN during spectrometry.

Nucleophillic Substitution occurs when an OH ion is reacted in a COLD AQUEOUS solution.  

The oxidation state is the NUMBER of ELECTRONS LOST compared to uncombined ATOM (0).

Standard enthalpy of combustion is the enthalpy change when 1 MOLE of a substance is completely BURNED IN OXYGEN under STANDARD STATES AND CONDITIONS.

Standard enthalpy of formation is the enthalpy change when 1 MOLE of a substance is formed from its ELEMENTS under STANDARD STATES AND CONDITIONS.