AQA A-Level Chemistry Paper 3, 2023
Every question from AQA A-Level Chemistry Paper 3, 2023: 36 questions, 90 marks, each with its mark scheme and topic.
- Question 1 17 marks
Preparation of Ethyl Ethanoate This question focuses on esterification, involving the role of concentrated sulphuric acid, identifying apparatus mistakes, explaining the use of sodium carbonate and anhydrous calcium chloride, determining the limiting reagent, calculating percentage yield, and identifying reasons for yield loss.
Organic Chemistry · Physical Chemistry · Required Practicals · 3.3.9 Carboxylic Acids and Derivatives · 3.1.2 Amount of Substance · Required Practical 7: Measuring the rate of reaction by an initial rate method
- Question 2 8 marks
Isomerism and Dehydration of Alcohols This question involves drawing displayed and skeletal formulas of isomers of pentan-2-ol, identifying functional group isomers, depicting alcohols that resist dehydration, completing a dehydration reaction mechanism with curly arrows, naming the mechanism, and drawing the structure of an isomeric product.
Organic Chemistry · 3.3.1 Introduction to Organic Chemistry · 3.3.5 Alcohols
- Question 3 12 marks
Analysis of Endomorphin-2 This question involves completing the structure of endomorphin-2, drawing the skeletal formula of proline, identifying reagents and conditions for peptide hydrolysis, analysing apparatus for thin-layer chromatography (TLC), explaining amino acid separation on a TLC plate, naming a suitable developing agent, and determining the Rf value for tyrosine (Tyr).
Organic Chemistry · 3.3.13 Amino Acids, Proteins and DNA
- Question 4 6 marks
Identification of Iron Salt Solutions This question involves identifying solutions L & M based on observations from chemical tests, explaining effervescence with sodium carbonate for L and writing ionic equations for the reactions observed during the tests.
Inorganic Chemistry · 3.2.6 Reactions of Ions in Aqueous Solution
- Question 5 10 marks
Enthalpy of Vaporisation and Polarity This question involves calculating the molar enthalpy of vaporisation ( Δ 𝐻 vap ΔH vap ) of water, explaining the polarity of ethanol, ethylamine, and dimethyl ether based on their molecular shapes and electronegativities, and analysing the trend in their boiling points by discussing intermolecular forces.
Physical Chemistry · 3.1.2 Amount of Substance · 3.1.3 Bonding
- Question 6 7 marks
Calcium Hydroxide and pH Calculation This question involves verifying that calcium hydroxide is in excess when reacting with hydrochloric acid and calculating the pH of a saturated solution of calcium hydroxide using solubility and the ionic product of water Kw
Physical Chemistry · 3.1.12 Acids and Bases · 3.1.2 Amount of Substance
- Question 7 1 mark
Number of Fundamental Particles in Mg This question involves identifying the correct number of protons, neutrons, and electrons in the Mg ion by interpreting atomic and ionic properties of magnesium.
Physical Chemistry · 3.1.1 Atomic Structure
- Question 8 1 mark
Relative Molecular Mass of Benzene-1,4-Dicarboxylic Acid This question involves calculating the Mr (relative molecular mass) of benzene-1,4-dicarboxylic acid using the atomic masses of its constituent element
Physical Chemistry · 3.1.2 Amount of Substance
- Question 9 1 mark
Substance with Significant Electron Delocalisation This question tests the identification of a substance exhibiting significant electron delocalisation, such as in a structure with conjugated π-bonds or a lattice of delocalised electrons.
Physical Chemistry · 3.1.3 Bonding
- Question 10 1 mark
Reaction with Standard Enthalpy Change Equal to Formation of Barium Chloride This question requires selecting the reaction equation representing the formation of BaCl₂(s) directly from its elements in their standard states under standard conditions.
Physical Chemistry · 3.1.4 Energetics
- Question 11 1 mark
Maxwell–Boltzmann Distribution Curve Question This question relates to the Maxwell–Boltzmann distribution of particle energies in a gaseous reactant, asking what the total area under the curve represents.
Physical Chemistry · 3.1.5 Kinetics
- Question 12 1 mark
Catalyst and Reaction Rate Question This question asks which statement best explains why the rate of reaction increases when a catalyst is used, without altering the temperature.
Physical Chemistry · 3.1.5 Kinetics
- Question 13 1 mark
The question involves calculating the equilibrium constant, Kₑ, for the dissociation of hydrofluoric acid (HF) in water. The equilibrium concentrations of HF, H⁺, and F⁻ are provided, and you are tasked with determining the value of Kₑ in mol dm⁻³.
Physical Chemistry · 3.1.6 Chemical Equilibria, Le Chatelier's Principle, and Kc
- Question 14 1 mark
Oxide with Highest Oxidation State This question asks you to determine which oxide contains the named element in its highest possible oxidation state, assessing your understanding of oxidation numbers and chemical compounds.
Physical Chemistry · 3.1.7 Oxidation, Reduction, and Redox Equations
- Question 15 1 mark
Water Vapourisation Process This question examines the understanding of molecular behaviour during the vaporisation of water, focusing on the changes in intermolecular forces, energy, and molecular arrangement.
Physical Chemistry · 3.1.3 Bonding
- Question 16 1 mark
Brønsted–Lowry Acid Behaviour This question tests the ability to identify which species can donate a proton (H⁺) in an aqueous solution, thereby acting as a Brønsted–Lowry acid.
Physical Chemistry · 3.1.12 Acids and Bases
- Question 17 1 mark
Halving the pH of NaOH Solution This question assesses understanding of pH changes when diluting a solution of sodium hydroxide or neutralising it with hydrochloric acid. It involves calculating how specific additions affect the concentration of hydroxide ions and subsequently the pH.
Physical Chemistry · 3.1.12 Acids and Bases
- Question 18 1 mark
Determination of Ka for a Weak Acid This question involves calculating the acid dissociation constant (Ka) for a weak acid using the given concentration and pH. It tests knowledge of the relationship between Ka, [H⁺], and the initial acid concentration.
Physical Chemistry · 3.1.12 Acids and Bases
- Question 19 1 mark
Trends in Period 3 Elements This question tests understanding of the periodic trends in Period 3 elements, including atomic radius, melting points, and first ionisation energies, and requires identifying an incorrect statement among the given options.
Inorganic Chemistry · 3.2.1 Periodicity
- Question 20 1 mark
Buffer Solution Formation This question examines the identification of a pair of solutions that, when mixed, form a buffer solution. A buffer maintains a relatively constant pH when small amounts of acid or base are added.
Physical Chemistry · 3.1.12 Acids and Bases
- Question 21 1 mark
Reaction of Barium with Water This question focuses on the observation when barium metal reacts with a large excess of water. The reaction produces hydrogen gas and barium hydroxide, and the question assesses the correct and complete description of this reaction.
Inorganic Chemistry · 3.2.2 Group 2, the Alkaline Earth Metals
- Question 22 1 mark
Identifying the Strongest Reducing Agent This question tests the ability to identify the species that acts as the strongest reducing agent, based on the tendency to lose electrons and reduce other substances, with a focus on halogens and halide ions.
Inorganic Chemistry · 3.2.3 Group 7(17), the Halogens
- Question 23 1 mark
Shapes of Ions This question assesses knowledge of the geometric shapes of ions, focusing on common coordination complexes and molecular ions, to identify an incorrect statement about their shapes.
Inorganic Chemistry · 3.2.5 Transition Metals
- Question 24 1 mark
Decolourisation of Potassium Manganate(VII) This question tests the ability to identify a compound that can reduce acidified potassium manganate(VII), causing it to decolourise. It focuses on recognising reducing agents among the given compounds.
Inorganic Chemistry · 3.2.5 Transition Metals
- Question 25 1 mark
Effect of Catalysts on Equilibrium This question examines the properties and effects of catalysts in equilibrium reactions, specifically addressing their impact on reaction rates and equilibrium constants without altering the thermodynamic properties of the reaction.
Physical Chemistry · 3.1.5 Kinetics
- Question 26 1 mark
Reaction Steps and Reagents This question involves identifying the correct reagent and condition for a specific step in a reaction scheme, focusing on the transformation of functional groups and conditions required for each step.
Organic Chemistry · 3.3.14 Organic Synthesis
- Question 27 1 mark
Processes and Catalysts This question tests understanding of industrial and natural chemical processes, specifically identifying which process does not utilise a heterogeneous catalyst.
Inorganic Chemistry · 3.2.5 Transition Metals
- Question 28 1 mark
Mole Fraction in Combustion This question assesses understanding of mole fractions in a chemical mixture, specifically calculating the mole fraction of butane (C₄H₁₀) in a mixture with oxygen (O₂) required for complete combustion based on the stoichiometry of the reaction.
Physical Chemistry · 3.1.2 Amount of Substance
- Question 29 1 mark
Reaction Products with KOH This question examines the ability to predict the possible products of a reaction between a bromocyclohexane derivative and potassium hydroxide (KOH). It requires knowledge of reaction pathways, such as substitution and elimination, and identifying which product cannot be formed.
Organic Chemistry · 3.3.3 Halogenoalkanes
- Question 30 1 mark
Role of Ozone in the Atmosphere This question evaluates understanding of the significance of ozone in the upper atmosphere. It requires identifying the correct reason for maintaining ozone concentration, particularly its role in protecting life on Earth by interacting with ultraviolet (UV) radiation.
Organic Chemistry · 3.3.3 Halogenoalkanes
- Question 31 1 mark
Conversion of Compound X to Alcohol This question focuses on identifying compound X, which undergoes a two-stage chemical reaction. The process involves treatment with concentrated H₂SO₄ to form an intermediate, followed by hydrolysis with excess H₂O to produce an alcohol. Understanding reaction pathways for alkenes, aldehydes, or amides is key.
Organic Chemistry · 3.3.14 Organic Synthesis
- Question 32 1 mark
Oxidation of 1-Phenylethanol This question asks for the correct balanced equation representing the oxidation of 1-phenylethanol. The process involves an oxidising agent, indicated by [O], and the products depend on whether the alcohol is oxidised to an aldehyde, ketone, or carboxylic acid. Understanding primary and secondary alcohol oxidation reactions is crucial.
Organic Chemistry · 3.3.5 Alcohols
- Question 33 1 mark
Distinguishing Two Carbonyl Compounds This question requires identifying a method to distinguish between two compounds with different carbonyl functional groups. Options include using spectroscopic techniques (infrared or mass spectrometry) or chemical reactions such as oxidation with potassium dichromate(VI) or reaction with Tollens’ reagent, which is specific to aldehydes. Understanding the reactivity and spectral differences of aldehydes and ketones is key.
Organic Chemistry · 3.3.6 Organic Analysis
- Question 34 1 mark
Identifying the Strongest Base This question assesses the ability to compare the basicity of various compounds, including amines and ammonium salts. Factors affecting basicity, such as electron-donating groups, resonance, and the presence of acidic protons, should be considered. Recognising the influence of the compound's structure on its ability to accept protons is crucial.
Organic Chemistry · 3.3.11 Amines
- Question 35 1 mark
Understanding Enzyme Specificity This question evaluates knowledge about enzyme structure, function, and specificity. It explores concepts like the impact of tertiary structure on substrate binding, inhibition mechanisms, and stereochemical preferences of enzymes when interacting with optical isomers of substrates.
Organic Chemistry · 3.3.13 Amino Acids, Proteins and DNA
- Question 36 1 mark
Mechanism of Cisplatin Binding to DNA This question tests understanding of ligand exchange reactions involving cisplatin, specifically how its ligands are replaced during the process of binding to DNA, which inhibits replication. The focus is on identifying which ligands, such as Cl⁻ or NH₃, are substituted in this interaction.
Organic Chemistry · 3.3.13 Amino Acids, Proteins and DNA