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Required practicals

From Mock A · Paper 2: Organic and Physical Chemistry
10.24 marks
50.0 cm³ of 1.00 mol dm⁻³ HCl was mixed with 50.0 cm³ of 1.00 mol dm⁻³ NaOH. The temperature rose by 6.8 K. Calculate the enthalpy of neutralisation (c = 4.18 J g⁻¹ K⁻¹; density 1.00 g cm⁻³).
From Mock A · Paper 3: Practical skills, all content and multiple choice
1.13 marks
Cyclohexene is prepared by heating cyclohexanol with concentrated phosphoric acid and distilling the product. Explain why the product distils off while cyclohexanol largely remains.
From Mock A · Paper 3: Practical skills, all content and multiple choice
1.24 marks
Describe how the crude distillate is purified.
From Mock A · Paper 3: Practical skills, all content and multiple choice
1.33 marks
10.0 g of cyclohexanol (Mᵣ 100) gave 5.74 g of cyclohexene (Mᵣ 82). Calculate the percentage yield.
From Mock A · Paper 3: Practical skills, all content and multiple choice
2.14 marks
In an iodine clock experiment, the time for the blue-black colour to appear is measured at different concentrations of potassium iodide. Explain why 1/time can be used as a measure of initial rate and why only a small amount of sodium thiosulfate is added.
From Mock A · Paper 3: Practical skills, all content and multiple choice
2.23 marks
A graph of 1/t against [KI] is a straight line through the origin. State the order with respect to iodide and explain.
From Mock A · Paper 3: Practical skills, all content and multiple choice
2.33 marks
Give three variables that must be controlled.
From Mock A · Paper 3: Practical skills, all content and multiple choice
3.14 marks
A burette has an uncertainty of ±0.05 cm³ per reading and a pipette ±0.06 cm³. A titre of 23.50 cm³ was measured using a 25.0 cm³ pipette. Calculate the percentage uncertainty in the titre and in the pipette volume.
From Mock A · Paper 3: Practical skills, all content and multiple choice
3.23 marks
Give three steps that ensure an accurate titration.
From Mock A · Paper 3: Practical skills, all content and multiple choice
3.33 marks
Explain how the uncertainty in the titre could be reduced, and why using a larger volume reduces percentage uncertainty.
From Mock A · Paper 3: Practical skills, all content and multiple choice
4.16 marks
Describe tests that would distinguish between solutions of copper(II) chloride, iron(III) sulfate and ammonium carbonate. Give the observations.
From Mock B · Paper 1: Inorganic and Physical Chemistry
2.24 marks
25.0 cm³ of 0.100 mol dm⁻³ NaOH was neutralised by 21.40 cm³ of sulfuric acid. Calculate the concentration of the sulfuric acid.
From Mock B · Paper 1: Inorganic and Physical Chemistry
4.14 marks
In a calorimetry experiment, 0.0250 mol of acid reacted with alkali in 50.0 g of solution. The temperature rose by 6.5 K. Calculate the enthalpy change per mole of acid. (c = 4.18 J g⁻¹ K⁻¹)
From Mock B · Paper 2: Organic and Physical Chemistry
14.12 marks
In thin-layer chromatography, a spot moved 2.4 cm and the solvent front 6.0 cm. Calculate the Rf value.
From Mock B · Paper 2: Organic and Physical Chemistry
15.23 marks
Burning 0.460 g of ethanol (Mr 46.0) heated 100 g of water by 25.0 K. Calculate the enthalpy of combustion of ethanol in kJ mol⁻¹. (c = 4.18 J g⁻¹ K⁻¹)
From Mock B · Paper 3: Practical skills, all content and multiple choice
1.13 marks
Describe how to make 250 cm³ of a standard solution of sodium carbonate from a weighed solid.
From Mock B · Paper 3: Practical skills, all content and multiple choice
1.23 marks
Titres (cm³) for a hydrochloric acid solution against 25.0 cm³ of sodium carbonate standard solution: 22.45, 22.60, 22.40, 22.50. Identify the concordant titres and calculate the mean titre.
From Mock B · Paper 3: Practical skills, all content and multiple choice
1.32 marks
Each burette reading has an uncertainty of ±0.05 cm³. Calculate the percentage uncertainty in a titre of 22.45 cm³.
From Mock B · Paper 3: Practical skills, all content and multiple choice
1.42 marks
Explain why the burette should be rinsed with the acid before filling.
From Mock B · Paper 3: Practical skills, all content and multiple choice
2.13 marks
In an iodine clock reaction, explain how the time for the blue-black colour to appear is used to measure the initial rate.
From Mock B · Paper 3: Practical skills, all content and multiple choice
2.24 marks
Results (data are illustrative, written for this paper):
[H₂O₂] / mol dm⁻³0.0200.0400.0600.080
Time / s120604130
Calculate 1/t for each and deduce the order with respect to H₂O₂.
From Mock B · Paper 3: Practical skills, all content and multiple choice
2.32 marks
Give two variables that must be kept constant.
From Mock B · Paper 3: Practical skills, all content and multiple choice
3.13 marks
Describe how to set up a cell to measure the EMF between a copper electrode in Cu²⁺(aq) and a zinc electrode in Zn²⁺(aq).
From Mock B · Paper 3: Practical skills, all content and multiple choice
3.22 marks
Explain why potassium nitrate is used in the salt bridge rather than potassium chloride.
From Mock B · Paper 3: Practical skills, all content and multiple choice
3.32 marks
The measured EMF was 1.04 V instead of 1.10 V. Suggest two reasons.
From Mock B · Paper 3: Practical skills, all content and multiple choice
4.13 marks
Cyclohexene was prepared by heating cyclohexanol with phosphoric acid and distilling. Describe how to purify the impure distillate.
From Mock B · Paper 3: Practical skills, all content and multiple choice
4.23 marks
5.00 g of cyclohexanol (Mr 100.0) gave 2.87 g of cyclohexene (Mr 82.0). Calculate the percentage yield.
From Mock B · Paper 3: Practical skills, all content and multiple choice
4.32 marks
Describe a test to confirm that the product contains an alkene.
From Mock B · Paper 3: Practical skills, all content and multiple choice
4.42 marks
Give two reasons for adding anti-bumping granules and heating gently.
From Mock B · Paper 3: Practical skills, all content and multiple choice
5.12 marks
Explain why the baseline on a TLC plate is drawn in pencil and why it is above the solvent level.
From Mock B · Paper 3: Practical skills, all content and multiple choice
5.22 marks
Amino acids are colourless. Describe how their spots can be located.
From Mock B · Paper 3: Practical skills, all content and multiple choice
75 marks
Ethanoic acid is titrated with sodium hydroxide. Explain the shape of the pH curve and choose a suitable indicator from methyl orange (pH 3.1–4.4) and phenolphthalein (pH 8.3–10.0).
From Mock C · Paper 3: Practical skills, all content and multiple choice
1.13 marks
Describe how to determine the enthalpy change of a reaction between zinc powder and copper(II) sulfate solution using a polystyrene cup.
From Mock C · Paper 3: Practical skills, all content and multiple choice
1.23 marks
Explain why the student plots a temperature–time graph and extrapolates the cooling line back to the time of mixing.
From Mock C · Paper 3: Practical skills, all content and multiple choice
1.34 marks
50.0 cm³ of 0.500 mol dm⁻³ CuSO₄ was used and the corrected ΔT was 25.2 K. Calculate ΔH for Zn + CuSO₄ → ZnSO₄ + Cu. (c = 4.18 J g⁻¹ K⁻¹; density 1.00 g cm⁻³)
From Mock C · Paper 3: Practical skills, all content and multiple choice
2.13 marks
Describe tests to show that a solution contains ammonium ions and sulfate ions.
From Mock C · Paper 3: Practical skills, all content and multiple choice
2.22 marks
Explain why hydrochloric acid is added before barium chloride in the sulfate test.
From Mock C · Paper 3: Practical skills, all content and multiple choice
2.33 marks
Describe a test for carbonate ions in solution.
From Mock C · Paper 3: Practical skills, all content and multiple choice
3.13 marks
Describe how a pH meter is calibrated and used to follow a titration.
From Mock C · Paper 3: Practical skills, all content and multiple choice
3.23 marks
From a pH curve for a weak acid titrated with NaOH, the pH at half-neutralisation was 4.20. Explain how this gives Ka and calculate it.
From Mock C · Paper 3: Practical skills, all content and multiple choice
4.13 marks
Describe how to prepare a sample of an ester by heating an alcohol and a carboxylic acid, and why heating under reflux is used.
From Mock C · Paper 3: Practical skills, all content and multiple choice
4.22 marks
Give two safety precautions in this preparation.
From Mock C · Paper 3: Practical skills, all content and multiple choice
4.33 marks
Explain how the ester can be separated and how the presence of unreacted acid can be removed.
From Mock C · Paper 3: Practical skills, all content and multiple choice
5.13 marks
A student measures the rate of reaction of magnesium with acid by collecting gas in a syringe. Explain how the initial rate can be found from a volume–time graph.
From Mock C · Paper 3: Practical skills, all content and multiple choice
5.23 marks
A balance reads to ±0.01 g. Calculate the percentage uncertainty when 0.12 g of magnesium is weighed, and suggest how to reduce it.
From Mock C · Paper 3: Practical skills, all content and multiple choice
5.32 marks
Explain why collecting gas in a gas syringe is more accurate than collecting it over water in a measuring cylinder.
Score 0 / 138 · 0 of 46 marked

This paper is written by Plasmo in the style of the AQA A-Level Chemistry exam. It is not a past paper and is not produced or endorsed by the exam board.

Required practicals Exam Questions: AQA A-Level Chemistry | Plasmo