Paper 1 June 2023 Chemistry- AS level OCR Breadth in Chemistry Paper 1 June 2023 (Mark S, Exams of Chemistry

Download Paper 1 June 2023 Chemistry- AS level OCR Breadth in Chemistry Paper 1 June 2023 (Mark S and more Exams Chemistry in PDF only on Docsity! Paper 1 June 2023 Chemistry- AS level OCR Breadth in Chemistry Paper 1 June 2023 (Mark Scheme) 2 Alkanes - First four alkanes are methane (CH4), Ethane (C2H6), Propane (C3H8), and Butane (C4H10) - single Bonded Alkenes and Alkynes - Contain double and triple bonds respectively. Alcohols - contain Hydroxyl group (OH) - suffix ol or hydroxy if a higher priority group is present - Diols contain two hydroxyl groups. * Geminal: 2 Hydroxyl groups on the same carbon * Vicinal: on adjacent carbons Common Names for Ketones - suffix one - Acetone (dimethylketone; 2- propanone) ; smallest ketone; similar as the figure - 2 pentanone (R= CH3CH2CH2) 3-butene-2-one - Naming ketones 5 The breakdown of Assessment Objectives for GCSE (9-1) in Chemistry B: Assessment Objective AO1 Demonstrate knowledge and understanding of scientific ideas and scientific techniques and procedures. AO1.1 Demonstrate knowledge and understanding of scientific ideas. AO1.2 Demonstrate knowledge and understanding of scientific techniques and procedures. AO2 Apply knowledge and understanding of scientific ideas and scientific enquiry, techniques and procedures. AO2.1 Apply knowledge and understanding of scientific ideas. AO2.2 Apply knowledge and understanding of scientific enquiry, techniques and procedures. AO3 Analyse information and ideas to interpret and evaluate, make judgements and draw conclusions and develop and improve experimental procedures. AO3.1 Analyse information and ideas to interpret and evaluate. AO3.1a Analyse information and ideas to interpret. AO3.1b Analyse information and ideas to evaluate. AO3.2 Analyse information and ideas to make judgements and draw conclusions. AO3.2a Analyse information and ideas to make judgements. AO3.2b Analyse information and ideas to draw conclusions. AO3.3 Analyse information and ideas to develop and improve experimental procedures. AO3.3a Analyse information and ideas to develop experimental procedures. AO3.3b Analyse information and ideas to improve experimental procedures. J258/01 Mark Scheme June 2023 Question Answer Marks AO element Guidance 1 (a) Potable water  1 1.1 (b) Any two from: Distillation  Water evaporated/boiled  (Water vapour) then condensed  2 1.2 IGNORE ‘distillation’ with incorrect detail IGNORE ‘water heated’ OR Any two from: Membrane filtration  Salty water forced through membrane at high pressure  Water molecules pass but dissolved salts don’t  IGNORE ‘filtration’ unqualified (c) (i) To kill micro-organisms/bacteria  1 1.1 ALLOW ‘remove bacteria’ ALLOW sterilises the water IGNORE ‘stop disease’ [too vague] Answer must be in terms of bacteria, microorganisms etc. [Allow germs] (ii) Toxic / poisonous  1 1.1 BOD taste IGNORE ‘harmful’ [too vague] / Cost 11 Question Answer Marks AO element Guidance (iii)  3 1.2 14 Question Answer Marks AO element Guidance 4 (a) Zinc is below carbon and Aluminium is above carbon in the reactivity series ✓ (so) aluminium oxide cannot be displaced by carbon ORA ✓ 2 1.2 ie links all three reactivities MUST MENTION DISPLACEMENT (b) (i) 2 1.2 DO NOT ALLOW any other ticks – these contradict those already scored (ii) gain ✓ atoms ✓ 2 1.1 (c) (i) energy is needed to melt/decompose aluminium oxide / energy is needed to provide the electricity ✓ 1 2.1 IGNORE cost IGNORE unqualified heating, must link to melting ALLOW difficult to break bonds / forces [so long as not in terms of molecular / intermolecular forces] (‘Energy to separate atoms etc’ not quite enough, we need why it needs that energy, i.e. forces.) (ii) Solution will contain positive aluminium and positive hydrogen ions (which compete) / aluminium more reactive than hydrogen (more stable) ✓ (and/so) hydrogen gas forms at the (cathode) (instead of aluminium metal) ✓ 2 3.1b ALLOW discussion of hydrogen or H+ Al3+ ions move to the positive electrode Oxygen is also formed ✓ The aluminium oxide is molten … ions … move. ✓ The negative electrode is made of steel 15 Question Answer Marks AO element Guidance 5 (a) ✓✓ 4 2.1 Any two correct in melting point/conducting electricity columns = 1 mark All four correct in these columns = 2 marks (b) ✓✓ 2 2.1 Any two correct = 1 mark All correct = 2 marks (c) 2 1.1 Formula Melting point Does it conduct electricity when molten? Does it conduct electricity when solid? Structure Magnesium oxide (MgO) (high) (yes) no (Giant) ionic ✓ Magnesium (Mg) (high) (yes) yes Metallic ✓ Silicon dioxide (SiO2) high no (no) (giant covalent) True False Chlorine and silicon dioxide have atoms joined by shared pairs of electrons ✓ Forces between chlorine molecules are strong ✓ Bonds between silicon atoms and oxygen atoms are strong ✓ Particles that conduct electricity Magnesium oxide Ions ✓ Magnesium Electrons ✓ 16 Question Answer Marks AO element Guidance 6 (a) ✓ 1 1.1 (b) ✓✓✓ 3 1.1 Two correct = 1 mark Three correct = 2 marks Four correct = 3 marks True False The proportion of greenhouse gases in the atmosphere has increased over the last 200 years ✓ The greenhouse effect is only caused by carbon dioxide and methane ✓ The Earth would be too hot to support life without the greenhouse effect ✓ Most scientists think that recent climate change can be explained by increased greenhouse gas emissions ✓ 19 Question Answer Marks AO element Guidance 8 (a) O2 ✓ 2 1.1 2SO2 AND 2SO3 ✓ 2.2 (b) 2 1.1 Rate of forward reaction = rate of reverse reaction ✓ The reaction stops when equilibrium is reached The reaction stops when there is 100% SO2 There will always be some SO2 present at equilibrium ✓ (c) (i) As the temperature rises, the percentage falls (AW, ORA) ✓ 1 3.1a ALLOW negative correlation ALLOW reversed causality answers (ii) 90 ✓ 1 2.2 ALLOW 91 (iii) First check the answer on answer line If answer = 83±1 award 2 marks Percentage converted 17±1 ✓ Percentage remaining 100 – 17±1 = 83±1 ✓ 2 2.2 ECF from percentage converted (iv) First check the answer on answer line 3 2.2 If answer = 50(%) award 3 marks Rearrangement % = SO3 x 80/SO2 ✓ Mark point 1 will be scored if mark point 2 is correct. % = 20 x 80/32 ✓ = 50(%) ✓ 20 Question Answer Marks AO element Guidance 9 (a) low boiling/melting point / does not conduct electricity / poor heat conductor / low density / colourless / odourless ✓ 1 1.1 IGNORE non-metal / full outer shell ALLOW gas (at room temperature) / insulator (b) Argon has a full outer shell / has 8 electrons in the outer shell / has a stable electronic structure/arrangement ✓ Chlorine gains one electron (to give a full (outer) shell) ✓ 2 2.1 IGNORE argon does not gain/lose electrons IGNORE chlorine has 7 electrons in the outer shell alone / chlorine does not have a full outer shell / is missing an electron DO NOT ALLOW chlorine loses or gains electrons ALLOW chlorine needs to gain electrons (c) (i) ✓✓ 2 3.2a All 4 correct = 2 marks Any 2 correct = 1 mark (ii) Sodium / potassium ✓ 1 3.2b ALLOW rubidium / caesium /francium IGNORE hydrogen/ Group II IGNORE fluorine (d) 22 ✓ 1 1.2 ALLOW 21.9 21 Question Answer Marks AO element Guidance 10 (a) (i) ✓ 1 1.2 DO NOT ALLOW -OH (ii) Methanoic acid ✓ 1 1.1 (b) 1 - 6.9 ✓ 1 1.1 ALLOW 0 (c) (i) Carbon dioxide ✓ 1 1.2 ALLOW CO2 DO NOT ALLOW CO2 (ii) Ca(HCOO)2 ✓ 1 2.1 ALLOW correct formula in any attempt at an equation ALLOW CaH2C2O4 / Ca(HCO2)2 / Ca2+(HCOO-)2 (d) Filtration/filter ✓ to remove calcium carbonate from the mixture ✓ 2 3.3b ALLOW filtration given in explanation but DO NOT ALLOW ‘filter to remove crystals’ (=0) IGNORE to remove solids/insoluble solids/excess substances Mark point 2 for identifying calcium carbonate as the impurity to be removed (e) (i) Evaporation/evaporate (AW) ✓ 1 1.2 IGNORE filtration / boiling / heating / crystallisation / put in an oven