OCR A LEVEL CHEMISTRY DEFINITIONS EXAM [ALREADY GRADED A+] WITH CORRECT DETAILED

OCR A LEVEL CHEMISTRY DEFINITIONS 2023 - 2024 EXAM [ALREADY GRADED A+] WITH CORRECT DETAILED Second electron affinity - ANSWER -The enthalpy change when 1 mole of gaseous 2 - ions forms from 1 mole of gaseous 1 - ions Second ionization energy - ANSWER -The energy change when 1 mole of gaseous 2+ ions forms from 1 mole of gaseous 1+ ions Shell - ANSWER -A group of atomic orbitals with the same principal quantum number Skeletal formula - ANSWER -A simplified structural formula drawn by removing hydrogen atoms from alkyl chains Spectator ions - ANSWER -Ions that are present but that play no part in a chemical reaction Spin -spin coupling - ANSWER -The interaction between spin states of non - equivalent nuclei that results in a group of peaks in an NMR spectrum Standard conditions - ANSWER -100kPa, 298K Standard electrode potential of a half cell - ANSWER -The e.m.f. of half a cell compared with a standard hydrogen half cell, measured at 298K with solution concentrations of 1 moldm -3 and 100kPa Standard enthalpy change of atomisation - ANSWER -The enthalpy change when 1 mole of gaseous atoms is formed from its element in its standard state Standard enthalpy change of formation - ANSWER -The enthalpy change when 1 mole of a compound is formed from it elements Standard enthalpy change of hydration - ANSWER -The enthalpy change when 1 mole of gaseous ions is dissolved in water Standard enthalpy change of solution - ANSWER -The enthalpy change when one mole of a solute is completely dissolved in water under standard conditions Standard entropy - ANSWER -The entropy content of one mole of a substance under standard conditions Standard entropy change of reaction - ANSWER -The entropy change when a reaction in the molar quantities expressed in a chemical equation happens under standard conditions, with all reactants and products being in their standard states Stationary phase - ANSWER -The phase that does not move in chromatography Stereoisomers - ANSWER -Species with the same structural formula but with a different arrangement of atoms in space Stoichiometry - ANSWER -The molar relationship between the relative quantities of substances taking part in a reaction Strong acid - ANSWER -An acid that completely dissociates in solution Structural isomers - ANSWER -Compounds with the same molecular formula but different structural formula Sub-shell - ANSWER -A group of the same type of atomic orbitals within a shell Substitution reaction - ANSWER -When an atom or group of atoms is replaced by a different atom or group of atoms Synthetic route - ANSWER -A series of reactions that can be used to change a starting chemical into a target molecule Amphoteric chemicals - ANSWER -Chemicals that can react with both acids and bases Anion - ANSWER -A negatively charged ion