A level chemistry Exam

Disproportionation - answer-The oxidation and reduction of the same element in a redox reaction Activation energy - answer-the minimum amount of energy required to start a chemical reaction standard enthalpy of formation - answer-enthalpy change if 1 mole of compound in standard state were formed directly from its elements Standard enthalpy of combustion - answer-the enthalpy change when 1 mole of a substance is completely burned in oxygen under standard conditions. Standard enthalpy of neutralisation - answer-The enthalpy change when one mole of water is produced in a neutralisation reaction under standard conditions. homogeneous catalyst - answer-a catalyst that is in the same phase as all the reactants and products in a reaction system heterogeneous catalyst - answer-A catalyst that is in a different phase from that of the reactant substances. Structural formula - answer-a formula that shows the arrangement of atoms in the molecule of a compound. Displayed formula - answer-Shows the relative positioning of all the atoms in a molecule and the bonds between them Skeletal formula - answer-A simplified organic formula, with hydrogen atoms removed from alkyl chains, leaving just a carbon skeleton and associated functional groups. Homologous series - answer-A series of organic compounds with the same functional group but with each successive member differing by CH2 Functional group - answer-a group of atoms responsible for the characteristic reactions of a particular compound. Alkyl group - answer-An alkane with a hydrogen atom removed, e.g. CH3, C2H5; are often shown as 'R'. Aliphatic - answer-Containing carbon atoms joined together in straight or branched chains. Non aromatic Alicyclic - answer-Containing carbon atoms joined together in a ring that is not aromatic Aromatic - answer-A compound containing a benzene ring Saturated - answer-Contains only single carbon-carbon bonds Homolytic fission - answer-Breaking of a covalent bond in such a way that one electron goes to each atom Heterolytic fission - answer-Breaking of a covalent bond in such a way that both electrons go to the same atom Radical - answer-A species with an unpaired electron Sigma bond - answer-a bond formed by head on overall of atomic orbitals pi bond - answer-sideways overlap of p orbitals Stereoisomers - answer-Compounds with the same structural formula but with a different arrangement of the atoms in space. E/Z isomerism - answer-A type of stereoisomerism in which different groups attached to each carbon of a C=C double bond may be arranged differently in space because of the restricted rotation of the C=C bond. cis-trans isomers - answer-A special case of E/Z isomerism in which two of the substituent groups are the same Cahn-Ingold-Prelog priority rules - answer-priority is assigned based on the atom bonded to the double bonded carbons, the higher the atomic number the higher the priority - used for E/Z isomers Electrophile - answer-An electron pair acceptor Nucleophile - answer-An electron pair donor