AS chemistry AQA unit 2

mhairireed's version from 2015-06-02 09:37

Section 1

Question Answer
atom economymass of desired product/total mass of reactants x 100
Bond dissociation energyenthalpy change required to break a covalent bond with all species in the gaseous state
dynamic equilibriumboth forward and backward rate are proceeding at the same rate. concs of products and reactants remain constant
enthalpy changeheat change at a constant pressure
homologous seriesa set of organic compounds with the same functional group. Compounds differ in hydrocarbon chain length.
Le chatelier's principleif a change in conditions is imposed on a system at equilibrium, the system will react in such a way as to oppose the effect of that change
Rate of reactionchange in concentration of a species per unit time.
biofuelA fuel derived or produced from renewable biological sources
free radicalspecies with an unpaired electron

Section 2

Question Answer
ionisation energyenthalpy change to remove one mole of electrons from a mole of isolated gaseous atoms or ions
mean bond enthalpyaverage value of the bond dissociation enthalpy for a given type of bond taken from a range of different compounds
molecular ionmolecule with one electron knocked off/ ion with biggest m/z value.
enthalpy change of combustionamount of heat energy given out when 1 mole of a substance is completely burned in oxygen with all the reactants and products on their standard states.
enthalpy change of formationheat change when one mole of substance is formed from its elements with all reactants and products in their standard states.
stoichiometrydescribes the simple whole number ratio in which chemical species react.
Hess's lawthe enthalpy change of a chemical reaction is independent of the route taken.

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