AS CHEMISTRY 7404/2 Paper 2 Organic and Physical Chemistry

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 by chain length / size / boiling point M3 not catalytic cracking M5 not condensation polymerisation 1 1 1 1 1 1 Question Marking guidance Additional Comments/Guidelines Mark 05.2 no polar bonds (in chain) / non-polar Do not allow if only C-H bonds mentioned as non polar 1 Question Marking guidance Additional Comments/Guidelines Mark 05.3 to prevent build-up of waste (in landfill) OR they can be broken down by natural processes 1 MARK SCHEME – AS CHEMISTRY – 7404/2 – JUNE 2021 20 Question Marking guidance Additional Comments/Guidelines Mark 06.1 METHOD 1 Stage 1 M1