plumiHow are the amounts of substances in reactions calculated?: OCR GCSE Combined Science B questions
Every OCR GCSE Combined Science B exam question on C5.2 How are the amounts of substances in reactions calculated?, 2018–2025, with its mark scheme and examiner’s report.
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Calculations
Q4(c)(ii)
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Q4(c)(iii)
The whole paper ↗Q9(a)(iii)
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Q4(b)(i)
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Q4(b)(ii)
The whole paper ↗Q4(b)(iii)
The whole paper ↗Q4(c)(i)
The whole paper ↗Q4(c)(ii)
The whole paper ↗Q5(a)(ii)
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Q5(b)(i)
The whole paper ↗Q5(c)
The whole paper ↗Q6(c)(ii)
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Q6(c)(iii)
The whole paper ↗Q7(b)(ii)
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Q5(a)
The whole paper ↗Q5(c)
The whole paper ↗Q8(c)(i)
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Q7(c)
The whole paper ↗Q8(a)(i)
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Q8(a)(ii)
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All 32 questions on How are the amounts of substances in reactions calculated?, as a list
- June 2025, Chemistry Paper 6 Higher, Q4(c)(ii) (2 marks): The mass of 1 mole of a substance is its relative formula mass in grams. Calculate the mass of 1 mole of hexane, C6H14. Use the Data Sheet. Mass of 1 mole of he
- June 2025, Chemistry Paper 6 Higher, Q4(c)(iii) (3 marks): Calculate the change in thermal energy of the water when 1 mole of hexane burns. Use the table and your answers to (c)(i) and (c)(ii). Change in thermal energy
- June 2024, Chemistry Paper 6 Higher, Q9(a)(iii) (4 marks): This is the balanced symbol equation for the decomposition of aluminium oxide by electrolysis: 2Al 2O3 4Al + 3O2 Calculate the mass of aluminium that will be pr
- June 2024, Combined Science Paper 8 Higher, Q4(b)(i) (2 marks): Calculate the relative formula mass of carbon dioxide. Use the Data and Equation Sheet. Relative formula mass = [2]
- June 2024, Combined Science Paper 8 Higher, Q4(b)(ii) (3 marks): The reading on the balance at the start of the experiment and after two minutes is shown. Start After two minutes 180.0 179.8 g g Calculate the number of moles
- June 2024, Combined Science Paper 8 Higher, Q4(b)(iii) (2 marks): In another experiment, 0.006 moles of carbon dioxide is produced. Calculate the number of molecules in 0.006 moles of carbon dioxide. 1 mole of a substance cont
- June 2024, Combined Science Paper 8 Higher, Q4(c)(i) (1 mark): If this 0.184 g of carbon dioxide was weighed on the balance shown in part (b)(ii), what would the balance display? Tick (✓) one box. 0.18 g 0.2 g 0.20 g 0.184
- June 2024, Combined Science Paper 8 Higher, Q4(c)(ii) (1 mark): Suggest one reason why the gas syringe method will give a more accurate number of moles of carbon dioxide than the balance method. [1]
- June 2023, Combined Science Paper 4 Foundation, Q5(a)(ii) (3 marks): When calcium carbonate reacts with hydrochloric acid, calcium chloride is formed. Calculate the relative formula mass of calcium chloride (CaCl 2). Use the Data
- June 2023, Combined Science Paper 4 Foundation, Q5(b)(i) (1 mark): Explain why the mass of the conical flask decreases during the reaction. [1]
- June 2023, Combined Science Paper 4 Foundation, Q5(c) (2 marks): Explain how Dev can develop his experiment to show that mass is conserved during the reaction. [2]
- June 2023, Chemistry Paper 6 Higher, Q6(c)(ii) (1 mark): How many moles of copper sulfate are formed? Use the symbol equation and your answer to (c)(i): CuO(s) + H2SO4(aq) CuSO4(aq) + H2O(l) Number of moles of copper
- June 2023, Chemistry Paper 6 Higher, Q6(c)(iii) (3 marks): Calculate the mass of copper sulfate crystals formed. The relative formula mass of the copper sulfate crystals is 249.6. Use your answer to (c)(ii) and the rela
- June 2022, Chemistry Paper 2 Foundation, Q7(b)(ii) (2 marks): Calculate the relative formula mass for FeF3. Use the Data Sheet. Relative formula mass = [2]
- June 2022, Combined Science Paper 4 Foundation, Q5(a) (3 marks): The table gives some information about three sugars that plants make. Relative Formula Sugar Formula Mass (RFM) Glucose C6H12O6 180 Fructose C6H12O6 180 Sucrose
- June 2022, Combined Science Paper 4 Foundation, Q5(c) (4 marks): Respiration produces carbon dioxide. To test for carbon dioxide we use limewater. The limewater turns cloudy because calcium carbonate forms. Calculate the perc
- November 2021, Chemistry Paper 2 Foundation, Q8(c)(i) (2 marks): Calculate the relative formula mass of magnesium hydroxide, Mg(OH)2. Use the Data Sheet. Relative formula mass = [2]
- November 2021, Combined Science Paper 4 Foundation, Q7(c) (3 marks): Potassium reacts with oxygen to form potassium oxide, K2O. Calculate the relative formula mass of potassium oxide. Use the Data Sheet. Relative formula mass of
- November 2020, Chemistry Paper 6 Higher, Q8(a)(i) (2 marks): Draw lines to connect the Avogadro constant and the mole with their definitions. Definition The amount of substance containing the same number of particles as t
- November 2020, Chemistry Paper 6 Higher, Q8(a)(ii) (3 marks): 1 mole of a substance contains 6.0 × 1023 molecules. Complete the table by calculating the missing values. Number of Relative Mass of Number of Substance moles
- November 2020, Chemistry Paper 6 Higher, Q8(b)(i) (3 marks): Calculate the number of moles of chlorine that react with 2 moles of phosphorus. Use the relationship: number of moles = mass of substance (g) relative formula
- November 2020, Chemistry Paper 6 Higher, Q8(b)(ii) (2 marks): Explain the effect on the mass of phosphorus chloride formed if 50 g of chlorine is added to 6.2 g of phosphorus. [2]
- June 2019, Combined Science Paper 4 Foundation, Q6(a)(iii) (3 marks): The hydrocarbons in crude oil are mostly alkanes. Octane is an alkane. Its molecular formula is C8H18. Determine the empirical formula of octane. Empirical form
- June 2019, Chemistry Paper 6 Higher, Q8(a)(iii) (3 marks): What is the maximum mass of zinc that can be extracted from 10 tonnes of zinc oxide? Mass of zinc = tonnes [3]
- June 2019, Combined Science Paper 8 Higher, Q1(a)(iii) (3 marks): The hydrocarbons in crude oil are mostly alkanes. Octane is an alkane. Its molecular formula is C8H18. Determine the empirical formula of octane. Empirical form
- June 2018, Chemistry Paper 2 Foundation, Q4(d) (2 marks): Jack measures the mass of the copper oxide at the start of the experiment. He measures the mass of the copper sulfate crystals at the end of the experiment. The
- June 2018, Chemistry Paper 2 Foundation, Q7(c)(i) (1 mark): Jane adds the five tablets to the beaker of acid. Calculate the total mass of the beaker and all of its contents at the start of the reaction. Total mass of bea
- June 2018, Chemistry Paper 2 Foundation, Q7(c)(ii) (1 mark): The mass of the beaker and its contents decreases during the experiment because carbon dioxide is made. Calculate the mass of carbon dioxide made in Jane’s expe
- June 2018, Chemistry Paper 2 Foundation, Q7(e)(i) (1 mark): Calculate the mass of calcium carbonate in 5 tablets. Mass of calcium carbonate = g [1]
- June 2018, Chemistry Paper 2 Foundation, Q7(e)(ii) (2 marks): Use the graph to predict how much carbon dioxide is made from five tablets. Show how you used the graph to find your answer. Mass of carbon dioxide = g [2]
- June 2018, Chemistry Paper 6 Higher, Q4(d)(i) (2 marks): Jane works out that there are 0.005 moles of calcium carbonate in 500 mg. Show by calculation that she is right. [2]
- June 2018, Chemistry Paper 6 Higher, Q4(d)(ii) (2 marks): Jane reacts 0.005 moles of calcium carbonate with dilute hydrochloric acid. CaCO3(s) + 2HCl(aq) CaCl2(aq) + CO2(g) + H2O(l) Calculate the mass of carbon dioxide
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