OCR GCSE Chemistry Higher Tier Tutors

Higher tier OCR GCSE Chemistry tutoring from Leading Tuition is one-to-one teaching for students entered for OCR's grades 9 to 4 papers, on either Chemistry A (Gateway Science, J248) or Chemistry B (Twenty First Century Science, J258). Each code has two Higher papers of 90 marks and 1 hour 45 minutes. We confirm the code first, then teach the calculation content that OCR prints in bold as Higher-only.

Which OCR chemistry code is the student sitting, J248 or J258?

OCR runs two separate chemistry GCSEs, and the Higher papers differ between them, so the code decides everything that follows. Chemistry A (Gateway Science) is J248 and its Higher papers are Paper 3 (J248/03) and Paper 4 (J248/04). Chemistry B (Twenty First Century Science) is J258 and its Higher papers are Breadth in chemistry (J258/03) and Depth in chemistry (J258/04). The qualification title is printed on the front of the specification and the question paper, and the chemistry teacher can confirm it. Our guide to both OCR chemistry specifications covers how the two routes were built.

OCR's specification for each code states that a learner is entered for one tier only: either the Foundation Tier or the Higher Tier, never a mixture. For Higher, that means both papers of the same code: Paper 3 and Paper 4 for J248, components 03 and 04 for J258. OCR's own overview pages list the same structure for J248 and J258, each with Higher tier shown as grades 9 to 4.

What this changes in our programme: the first lesson is a code check against the student's exercise books and mock papers, and we plan the term backwards from the right pair of papers.

What does OCR mark as Higher-only in the calculation content?

Both specifications use typography to mark tier. J248 says: “Statements shown in bold type will only be tested in the Higher Tier papers. All other statements will be assessed in both Foundation and Higher Tier papers.” J258 says: “Emboldened statements will only be assessed in Higher Tier papers.” We read the marking from the typeface in OCR's published PDFs; where only part of a statement is bold, only those words are Higher-only. One note on symbols: the tick symbol in the J248 content tables and the words “(separate science only)” inside some J258 statements say something different, namely that the content belongs to separate-science chemistry. They are not tier markers, and a statement is Higher-only only if its own words are in bold.

The largest connected block of bold statements in both codes is quantitative chemistry, the chain that runs from the mole to concentration to gas volumes. In J248 OCR prints these as Higher-only:

• C3.1g: “recall and use the definitions of the Avogadro constant (in standard form) and of the mole”, with the bold To-include note “the calculation of the mass of one atom/molecule”.
• C3.1h: “explain how the mass of a given substance is related to the amount of that substance in moles and vice versa”.
• C3.1k: “deduce the stoichiometry of an equation from the masses of reactants and products and explain the effect of a limiting quantity of a reactant”.
• C3.1l: “use a balanced equation to calculate masses of reactants or products”.
• C5.1a: “explain how the concentration of a solution in mol/dm³ is related to the mass of the solute and the volume of the solution”.
• C5.1c: “explain the relationship between the volume of a solution of known concentration of a substance and the volume or concentration of another substance that react completely together”, with the bold To-include note “titration calculations”. The neighbouring C5.1b, describing the technique of titration, is in plain type.
• C5.1d: “describe the relationship between molar amounts of gases and their volumes and vice versa”.
• C5.1e: “calculate the volumes of gases involved in reactions using the molar gas volume at room temperature and pressure (assumed to be 24 dm³)”.
• C5.1f: “explain how the mass of a solute and the volume of the solution is related to the concentration of the solution”.
• The maths outcome CM3.1ii and its twin CM5.1i: “calculations with numbers written in standard form when using the Avogadro constant”. In CM3.1iv and CM5.1iii only the words “particularly from mass to moles” are bold, attached to the plain-type “convert units where appropriate”.

In J258 the same chain sits in chapters C5.3 and C5.4, numbered by outcome rather than by letter:

• C5.3 outcome 4: “recall and use the definitions of the Avogadro constant (in standard form) and of the mole”.
• C5.3 outcome 5: “explain how the mass of a given substance (in grams) is related to the amount of that substance in moles and vice versa and use the relationship”.
• C5.3 outcome 6: “deduce the stoichiometry of an equation from the masses of reactants and products and explain the effect of a limiting quantity of a reactant”.
• C5.3 outcome 7: “use a balanced equation to calculate masses of reactants or products”.
• C5.3 outcome 9: “carry out calculations with numbers written in standard form when using the Avogadro constant”.
• C5.3 outcome 14: “describe the relationship between molar amounts of gases and their volumes and vice versa, and calculate the volumes of gases involved in reactions, using the molar gas volume at room temperature and pressure (assumed to be 24 dm³) (separate science only)”.
• C5.4 outcome 2: “explain how the mass of a solute and the volume of the solution is related to the concentration of the solution and calculate concentration using the formula”.
• C5.4 outcome 3: “explain how the concentration of a solution in mol/dm³ is related to the mass of the solute and the volume of the solution and calculate the molar concentration using the formula”.
• C5.4 outcome 9: “explain the relationship between the volume of a solution of known concentration of a substance and the volume or concentration of another substance that react completely together (separate science only)”.

What this changes in our programme: these statements form a dependency chain, so we teach them in that order whatever the school's scheme of work says. A student who cannot move between mass and moles stalls on reacting masses, then limiting reactants, then concentration, with titration calculations and gas volumes at the end of the line. The first sessions are short timed sets that test each link separately, and we do not move on while a link is wrong. In J248 the mole links (C3.1g to C3.1l) sit in topic C3 and the concentration and gas-volume links (C5.1a to C5.1f) in topic C5, so we revisit the earlier links when the later ones arrive.

What else does OCR print in bold as Higher-only?

The other bold statements fall into five themes: redox and electrolysis, acids and pH, energy and the particle model, equilibrium with industrial conditions, and polymers. We group them as a tutor plans lessons, not as the specification numbers its pages.

J248, redox and electrolysis. C3.1e, “construct balanced ionic equations”. In C3.1b only the words in bold are Higher-only: “use the names and symbols of common elements and compounds and the principle of conservation of mass to write formulae and balanced chemical equations and half equations”. C3.3b: “explain reduction and oxidation in terms of gain or loss of electrons, identifying which species are oxidised and which are reduced”. In C3.4d the outcome “describe electrolysis in terms of the ions present and reactions at the electrodes” is plain type; in its To-include cell only the words half equations are bold, in “the equations and half equations of the reactions at the electrodes”.

J248, acids, pH and energy. C3.3g: “use and explain the terms dilute and concentrated (amount of substance) and weak and strong (degree of ionisation) in relation to acids”, with the bold note “ratio of amount of acid to volume of solution”. C3.3i: “describe neutrality and relative acidity and alkalinity in terms of the effect of the concentration of hydrogen ions on the numerical value of pH (whole numbers only)”, with the bold note “pH of titration curves”. C3.3j: “use the idea that as hydrogen ion concentration increases by a factor of ten, the pH value of a solution decreases by one”. C3.2d: “calculate energy changes in a chemical reaction by considering bond making and bond breaking energies”. C1.1c: “explain the limitations of the particle model in relation to changes of state when particles are represented by inelastic spheres (e.g. like bowling balls)”.

J248, equilibrium, industry and polymers. C5.1k: “explain why a particular reaction pathway is chosen to produce a specified product given appropriate data”. C5.3c: “predict the effect of changing reaction conditions on equilibrium position and suggest appropriate conditions to produce as much of a particular product as possible”, with “Le Chatelier's principle concerning concentration, temperature and pressure”. C6.1c: “evaluate alternative biological methods of metal extraction”. C6.1d: “explain the trade-off between rate of production of a desired product and position of equilibrium in some industrially important processes”, naming the Haber process and Contact process. C6.1e: “interpret graphs of reaction conditions versus rate”. C6.1f: “explain how the commercially used conditions for an industrial process are related to the availability and cost of raw materials and energy supplies, control of equilibrium position and rate”. C6.2e: “explain the basic principles of condensation polymerisation”. C6.2f: “describe practical techniques to make a polymer by condensation”.

J258, redox and electrolysis. In C3.2 outcome 3 only the words and ionic equations are bold, at the end of “write formulae and balanced chemical equations”. C3.3 outcome 4: “use the names and symbols of common elements and compounds and the principle of conservation of mass to write half equations”. C3.3 outcome 5 and C4.5 outcome 3 both read “explain reduction and oxidation in terms of gain or loss of electrons, identifying which species are oxidised and which are reduced”; outcome 2 of C4.5, on loss or gain of oxygen, is plain type. C3.2 outcome 6: “evaluate alternative biological methods of metal extraction (bacterial and phytoextraction)”.

J258, acids, pH and energy. C6.1 outcome 5: “use and explain the terms dilute and concentrated (amount of substance) and weak and strong (degree of ionisation) in relation to acids including differences in reactivity with metals and carbonates”. C6.1 outcome 6: “use the idea that as hydrogen ion concentration increases by a factor of ten the pH value of a solution decreases by one”. C6.1 outcome 7: “describe neutrality and relative acidity and alkalinity in terms of the effect of the concentration of hydrogen ions on the numerical value of pH (whole numbers only)”. C1.2 outcome 5: “calculate energy changes in a chemical reaction by considering bond breaking and bond making energies”. C1.1 outcome 2: “explain the limitations of the particle model in relation to changes of state when particles are represented by inelastic spheres”.

J258, equilibrium, rates, industry, polymers and risk. C6.3 outcome 3: “predict the effect of changing reaction conditions (concentration, temperature and pressure) on equilibrium position and suggest appropriate conditions to produce a particular product”, including that catalysts increase rate but do not affect yield and the disadvantages of using very high temperatures or pressures. C6.4 outcome 3 asks for the commercially used Haber process conditions to be related to the availability and cost of raw materials and energy supplies, control of equilibrium position and rate. C6.4 outcome 4: the trade-off between rate of production of a desired product and position of equilibrium in some industrially important processes. C6.4 outcome 8: “explain why a particular reaction pathway is chosen to produce a specified product given appropriate data such as atom economy (if not calculated), yield, rate, equilibrium position, usefulness of by-products and evaluate the sustainability of the process”. C4.2 outcome 3: “explain the basic principles of condensation polymerisation” with the functional-group detail OCR sets out. C6.2 outcome 9: “interpret graphs of reaction conditions versus rate (separate science only)”. In C6.2 outcome 7, “suggest practical methods for determining the rate of a given reaction”, the lead-in “measurement of physical factors:” and its sub-points colour change and formation of a precipitate are bold, while the gas-syringe and mass-change sub-points are plain type. In the Ideas about Science chapter, this sub-point is bold: “distinguish between perceived and calculated risk”.

What this changes in our programme: each theme becomes a block of lessons with a single type of exam answer at the end of it. Redox and half equations are taught as a writing skill with a fixed order of steps. Acid and pH statements are taught as short explanations that state the ten-fold link between hydrogen ion concentration and pH. Equilibrium and industrial-conditions statements are taught as the longest answers in the course, because they ask for a decision from the data given. Partial-bold items get their own short drills, because one bold phrase in a plain statement is easy to miss.

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How do the Higher papers spread this content?

J248 divides the course between its two Higher papers by topic. OCR's specification says Paper 3 assesses content from Topics C1–C3 and C7, and Paper 4 assesses Topics C4–C6 and C7, “with assumed knowledge of Topics C1–C3”. Paper 4 also carries synoptic assessment. Reading the bold statements against that split gives a practical result: the mole, reacting-mass, limiting-reactant, redox, pH and bond-energy statements all sit in C3, so they are examined in Paper 3, while the concentration, titration, gas-volume, equilibrium and industrial-conditions statements sit in C5 and C6, so they are examined in Paper 4, a paper that also assumes the C3 mole work is secure. J258 splits differently. OCR says its Breadth in chemistry and Depth in chemistry components each assess content from across all eight teaching chapters, so every bold statement can appear on either paper.

Working from those figures: 15 of a J248 paper's 90 marks are multiple choice, 16.7%, and the other 75 are written answers. On J258's Depth paper the two extended responses are worth at least 12 of 90 marks, 13.3%. Converting the assessment-objective table to the share of each 90-mark J258 paper gives AO1 48%, AO2 36% and AO3 16% on Breadth, and AO1 32%, AO2 44% and AO3 24% on Depth. OCR also states that a scientific or graphical calculator is permitted on all four components of each code, and that questions assessing mathematical skills at Higher tier will not be lower in demand than those in assessment for the Foundation Tier of GCSE Mathematics.

What this changes in our programme: timing and answer style are trained by paper type. 105 minutes for 90 marks is 1.17 minutes a mark, so a six-mark answer has roughly seven minutes and an AO3-heavy Depth question needs a planned approach to data. For J248 we set Paper 3 practice from C1–C3 material and Paper 4 practice from C4–C6 with C3 mole questions deliberately mixed in. For J258 we use Breadth for short mixed retrieval and Depth for sustained explanations and the Level of Response answers. OCR's J248 specification prints a Periodic Table in its appendix 5h, with a key giving atomic number, symbol, name and relative atomic mass, and our mole-calculation practice is built around reading those quantities from that layout.

What did the Higher boundaries do across the four June series in our tables?

OCR's specifications say there is “one examination series available each year in May/June to all learners”, so the series in our tables are four consecutive June series, each taken from OCR's published GCSE grade boundaries document. The tables below show the Higher tier of one code at a time. The two codes have separate papers, so their figures are never added or averaged together. Each table lists the raw mark needed for each grade, as OCR prints it.

J248 Chemistry A, Higher tier

Overall, Paper 3 plus Paper 4, out of 180 marks:

The grade 4 boundary rose in each series, from 60 to 76 marks. The working is 76 − 60 = 16 marks. As a share of 180 that is 33.3%, 37.8%, 40.6% and 42.2% in turn. The grade 9 boundary ran from 147 to 163 marks, which is 81.7% to 90.6% of 180, and the distance between the grade 4 and grade 3 boundaries was 9, 10, 10 and 11 marks in turn. OCR publishes the paper-level figures as notional boundaries and says: “Please note that ‘grades’ at component level do not automatically add up to the same grade at qualification level.” Read the next table with that caveat in mind.

On Paper 3 the grade 4 notional boundary was 32, 38, 44 and 43 out of 90 in turn; on Paper 4 it was 28, 30, 29 and 33.

J258 Chemistry B, Higher tier

Overall, Breadth (03) plus Depth (04), out of 180 marks:

The grade 4 boundary here ran from 41 to 57 marks, again a rise of 16 marks (57 − 41 = 16), or 22.8%, 25.0%, 31.1% and 31.7% of 180 in turn. The grade 9 boundary ran from 128 to 141 marks, which is 71.1% to 78.3% of 180, and the grade 4 to grade 3 distance was 10, 9, 10 and 9 marks in turn. The two components follow the same caveat from OCR about notional component grades.

On Breadth the grade 4 notional boundary was 18, 23, 30 and 27 out of 90 in turn; on Depth it was 23, 22, 26 and 30.

What this changes in our programme: a boundary that moved by sixteen marks in four series cannot be treated as a fixed target. We mark a student's practice papers against the lowest and the highest grade 4 boundary in the relevant code's table, which gives a band rather than a single number, and we aim for a margin above the top of that band before a mock rather than a pass mark that happens to match one past year. Within a code the paper-level figures also tell us where marks have been hardest: on J258 the Breadth and Depth boundaries did not move together from one series to the next, so a student's Breadth and Depth scores are tracked separately.

What does OCR say about grades 9 to 4 and the allowed grade 3?

For both J248 and J258 OCR's specification says Higher Tier assesses grades 9 to 4, and adds: “An allowed grade 3 may be awarded on the Higher Tier option for learners who are a small number of marks below the grade 3/4 boundary.” Entry is to one tier only, so the allowed grade 3 is the board's provision for a Higher entrant a few marks below the grade 4 boundary. On J248, retakes follow the board's rule: learners “retake all the papers within the relevant tier to be awarded the qualification”, and with one May/June series a year, a retake is a full re-sit of both Higher papers.

What this changes in our programme: the choice of tier is made with the student's mock evidence, on the marks they are actually scoring on Higher papers rather than on a hoped-for grade. If a student is regularly a few marks short of the grade 4 boundaries in the tables above, we say so plainly and go through the options with the family and the school; families weighing the other tier can start from our Foundation tier OCR GCSE Chemistry tutoring page. Students who are secure on Higher get a programme aimed at the top of the range, using the grade 9 and grade 7 rows of the tables.

How is a term of Higher tier OCR GCSE Chemistry tutoring built from this?

1. We confirm the code and the papers: J248 Paper 3 and Paper 4, or J258 Breadth and Depth.
2. We run a diagnostic on the calculation chain, from mass and moles to concentration and gas volumes, because it carries the largest block of Higher-only statements in both codes.
3. We teach the remaining Higher-only themes in the order the school reaches them: redox and half equations, acids and pH, energy, equilibrium and industrial conditions, and condensation polymerisation.
4. We set timed practice by paper type, with 1.17 minutes a mark as the working pace and a calculator allowed.
5. We mark practice papers against the boundary band for the student's code and report the result back to the family with the next three topics to fix.

Students taking Higher tier in more than one science can also read our Higher tier OCR GCSE Biology tutoring page, which is built the same way from OCR's own documents for the biology codes.

Higher tier OCR GCSE Chemistry questions answered