1. General The mark scheme for each question shows: • the marks available for each part of the question • the total marks available for the question • the typical answer or answers which are expected • extra information to help the examiner make his or her judgement and help to delineate what is acceptable or not worthy of credit or, in discursive answers, to give an overview of the area in which a mark or marks may be awarded. The extra information in the ‘Comments’ column is aligne...

Question Marking guidance Additional Comments/Guidelines Mark 05.1 Step 1 M1 fractional distillation M2 separated into mixtures of compounds with similar boiling points / similar sized molecules Step 2 M3 (thermal) cracking M4 to make alkenes / propene / shorter molecules Step 3 M5 (addition) polymerisation M6 molecules joined together or to produce long chain molecule For each step the two marks are independent M2 to separate naphtha from other compounds; to separate compounds...