AQA GCSE COMBINED SCIENCE: TRILOGY 8464/C/2H Chemistry Paper 2H Mark scheme June 2023

AQA GCSE COMBINED SCIENCE: TRILOGY 8464/C/2H Chemistry Paper 2H Mark scheme June 2023. CH4 + 2 O2 → CO2 + 2 H2O 1 AO2 5.7.1.3 Question Answers Extra information Mark AO / Spec. Ref. 01.2 hydrocarbon molecules in petrol have fewer carbon atoms than those in diesel petrol has a lower boiling point (range) than diesel allow converse throughout allow petrol is more flammable than diesel allow petrol is less viscous than diesel 1 1 AO3 5.7.1.3 Question Answers Extra information Mark AO / Spec. Ref. 01.3 oxygen 1 AO1 5.8.1.2 Question Answers Extra information Mark AO / Spec. Ref. 01.4 air allow the atmosphere allow from volcanoes 1 AO1 5.9.1.1 5.9.3.1 Question Answers Extra information Mark AO / Spec. Ref. 01.5 global dimming 1 AO2 5.9.3.1 MARK SCHEME – GCSE COMBINED SCIENCE: TRILOGY – 8464/C/2H – JUNE 2023 8 Question Answers Extra information Mark AO / Spec. Ref. 01.6 (carbon monoxide is) colourless or (carbon monoxide is) odourless ignore clear 1 AO1 5.9.3.2 Question Answers Extra information Mark AO / Spec. Ref. 01.7 (diesel) burns at a high temperature or (diesel) burns at a temperature greater than 100 °C (which is) above the boiling point of water 1 1 AO2 AO3 5.2.2.1 5.9.3.1 Question Answers Extra information Mark AO / Spec. Ref. 01.8 sulfur dioxide (is produced when diesel is burnt) (which causes) acid rain (which results in) any one from: • damage to buildings / statues / bridges • damage to trees / plants • damage to aquatic life • acidification of lakes / rivers / soil • respiratory problems allow (which affects) asthma 1 1 1 AO1 5.9.3.1 5.9.3.2 Total Question 1 12 MARK SCHEME – GCSE COMBINED SCIENCE: TRILOGY – 8464/C/2H – JUNE 2023 9 Question 2 Question Answers Extra information Mark AO / Spec. Ref. 02.1 stationary phase 1 AO1 5.8.1.3 RPA12 Question Answers Extra information Mark AO / Spec. Ref. 02.2 any one from: (the substances) • move at different speeds • have different solubilities • have different attractions for the (chromatography) paper 1 AO2 5.8.1.3 RPA12 Question Answers Extra information Mark AO / Spec. Ref. 02.3 1 1 AO1 5.8.1.3 RPA12 Question Answers Extra information Mark AO / Spec. Ref. 02.4 (Rf = ) 4.77 5.30 = 0.9 1 1 AO2 5.8.1.3 RPA12 MARK SCHEME – GCSE COMBINED SCIENCE: TRILOGY – 8464/C/2H – JUNE 2023 10 Question Answers Mark AO / Spec. Ref. 02.5 Level 3: The method would lead to the production of a valid outcome. The key steps are identified and logically sequenced. 5–6 AO1 5.8.1.3 Level 2: The method would not necessarily lead to a valid outcome. Most steps are identified, but the method is not fully logically sequenced. 3–4 Level 1: The method would not lead to a valid outcome. Some relevant steps are identified, but links are not made clear. 1–2 No relevant content 0 Indicative content • draw a pencil line • near the bottom edge of the (chromatography) paper • put a small dot of black ink on the pencil line • put a small volume of water / solvent in a beaker • place the (chromatography) paper in the solvent • the dots of ink should be above the level of the water / solvent • support the paper in this position • put a lid on the beaker • leave to run • mark position of solvent front • remove from beaker and leave to dry • determine Rf values • measure distance of all dots from start line • measure distance of solvent front from start line • calculate Rf values for all dots • compare with known Rf values