Explain why the mass appears to decrease when a metal carbonate is heated in an open crucible.
From Paper 3, Higher
43 marks
Explain how to make a soluble salt from an acid and an alkali.
From Paper 3, Higher
54 marks
Describe an experiment to investigate the electrolysis of an aqueous solution using inert electrodes.
From Paper 3, Higher
83 marks
Calculate the empirical formula of a compound containing 2.4 g of carbon and 0.6 g of hydrogen.
From Paper 3, Higher
92 marks
Write a balanced equation for the reaction of calcium carbonate with hydrochloric acid.
From Paper 3, Higher
112 marks
How many atoms are in 0.5 moles of carbon? (Avogadro constant = 6.02 × 10²³)
From Paper 3, Higher
123 marks
Explain why ethanoic acid reacts more slowly with magnesium than hydrochloric acid of the same concentration.
From Paper 3, Higher
143 marks
Calculate the mass of sodium hydroxide needed to make 250 cm³ of a 0.400 mol/dm³ solution. (Mr NaOH = 40)
From Paper 3, Higher
153 marks
Explain why the pH of acid falls when its concentration increases.
From Paper 3, Higher
164 marks
4.0 g of copper(II) oxide reacts with sulfuric acid. Calculate the maximum mass of copper(II) sulfate (Mr 159.5) that can be formed. (Mr CuO = 79.5) CuO + H₂SO₄ → CuSO₄ + H₂O
From Paper 3, Higher
173 marks
Explain what is meant by a limiting reactant and identify it when 2.4 g of magnesium reacts with 100 cm³ of 1.0 mol/dm³ HCl. Mg + 2HCl → MgCl₂ + H₂
From Paper 3, Higher
183 marks
Balance the equation: Fe₂O₃ + C → Fe + CO₂
From Paper 3, Higher
193 marks
Calculate the percentage by mass of nitrogen in ammonium nitrate, NH₄NO₃. (Ar N = 14, H = 1, O = 16)
From Paper 3, Higher
202 marks
Convert a concentration of 0.20 mol/dm³ of HCl into g/dm³. (Mr HCl = 36.5)
From Paper 3, Higher
213 marks
Calculate the volume of oxygen needed to burn 60 cm³ of methane completely. CH₄ + 2O₂ → CO₂ + 2H₂O
From Paper 3, Higher
242 marks
Calculate the relative formula mass (Mr) of CaCO₃. (Relative atomic masses: Ca = 40, C = 12, O = 16)
From Paper 3, Higher
256 marks
Describe how to prepare a pure, dry sample of copper(II) sulfate crystals from copper(II) oxide and dilute sulfuric acid.
From Paper 3, Higher
264 marks
Predict the products at each electrode in the electrolysis of copper(II) chloride solution and write the half equation at the cathode.
From Paper 3, Higher
273 marks
Explain the difference between exothermic and endothermic reactions, with an example of each.
From Paper 3, Higher
301 mark
What is the pH of a neutral solution?
Score 0 / 60 · 0 of 20 marked
This paper is written by Plasmo in the style of the OCR GCSE Chemistry exam. It is not a past paper and is not produced or endorsed by the exam board.
Chemical reactions Exam Questions: OCR GCSE Chemistry | Plasmo