OCR A Level Chemistry Exam

acid - answer-A species that is a proton donor. activation energy - answer-The minimum amount of kinetic energy that particles need to have in order to react when they collide addition polymer - answer-A very long molecular chain formed by repeated addition reactions of many unsaturated alkene molecules (monomers). addition polymerisation - answer-The process in which unsaturated alkene molecules (monomers) add on to a growing polymer chain one at a time to form a very long saturated molecular chain (the addition polymer). addition reaction - answer-A reaction in which a reactant is added to an unsaturated molecule to make a saturated molecule. adsorption - answer-The process that occurs when a gas, liquid or solute is held to the surface of a solid or, more rarely, a liquid. alicyclic hydrocarbon - answer-A hydrocarbon with carbon atoms joined together in a ring structure. aliphatic hydrocarbon - answer-A hydrocarbon with carbon atoms joined together in straight or branched chains. alkali - answer-A type of base that dissolves in water forming hydroxide ions, OH- (aq) ions. alkanes - answer-The homologous series with the general formula: CnH2n+2. alkyl group - answer-An alkane with a hydrogen atom removed, e.g. CH3, C2H5; alkyl groups are often shown as 'R'. amount of substance - answer-The quantity whose unit of the mole. Chemists use 'amount of substance' as a means of counting atoms. anhydrous - answer-A substance that contains no water molecules. anion - answer-A negatively charged ion. atom economy - answer-atom economy = molecular mass of the desired product ×100 sum of molecular masses of all products