Edexcel A-Level Chemistry sample questions and answers (9CH0)
Guide overview All 19 topics Sample questions Papers and weighting Look inside Questions and answers
57 sample questions and answers
Taken from every topic of Edexcel A-Level Chemistry, specification 9CH0. The full guide has 1,534.
Paper 1, Paper 3
Atomic Structure and the Periodic Table
68 questions in the guide, across 5 subtopics. More from this topic
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Protons, neutrons, electrons and isotopes
What is meant by the mass number of an atom?
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The total number of protons and neutrons in the nucleus of an atom -
Protons, neutrons, electrons and isotopes
How is the number of electrons in a negative ion calculated?
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Number of electrons = number of protons plus the magnitude of the charge -
Relative atomic mass and the mass spectrum
Why does the mass spectrum of a diatomic element show multiple peaks?
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Because peaks correspond to all possible combinations of isotopes in the molecule
Paper 1, Paper 2, Paper 3
Bonding and Structure
69 questions in the guide, across 4 subtopics. More from this topic
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Ionic bonding
How are cations formed?
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By an atom losing one or more electrons. -
Ionic bonding
What is an isoelectronic series?
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A set of ions (or atoms) that all have the same number of electrons and the same electron configuration. -
Covalent bonding, dative bonding and the shapes of molecules
Which is stronger and shorter, a C-C single bond or a C=C double bond?
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The C=C double bond is shorter and stronger.
Paper 1, Paper 2, Paper 3
Redox I
35 questions in the guide, across 2 subtopics. More from this topic
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Oxidation numbers
What is the oxidation number of fluorine in its compounds?
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Always -1. -
Oxidation numbers
In Cr₂O₇²⁻, what oxidation number does chromium take?
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+6 (seven oxygens at -2 give -14; ion charge -2, so the two Cr total +12, i.e. +6 each). -
Oxidation, reduction, disproportionation and half-equations
In general, how do metals form ions, and what happens to their oxidation number?
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They lose electrons to form positive ions, so their oxidation number increases.
Paper 1, Paper 3
Inorganic Chemistry and the Periodic Table
168 questions in the guide, across 11 subtopics. More from this topic
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Flame tests and how they work
What flame colour is produced by lithium compounds?
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Crimson/red -
Thermal decomposition of nitrates and carbonates
What gaseous products are released when calcium nitrate decomposes on heating?
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Nitrogen dioxide and oxygen -
Carrying out flame tests and testing the gases
Where in the Bunsen flame should the wire be held during a flame test?
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At the edge of a non-luminous Bunsen flame
Paper 1, Paper 2, Paper 3
Formulae, Equations and Amounts of Substance
134 questions in the guide, across 8 subtopics. More from this topic
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The mole, molar mass and empirical formula
State the formula used to calculate the amount of substance in moles from mass.
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n = m/M, where n is the amount in moles, m is the mass in grams, and M is the molar mass in g mol⁻¹. -
The ideal gas equation and molar volume
Calculate the amount of substance when pressure = 158000 Pa, volume = 0.0016 m³, gas constant = 8.31 J K⁻¹ mol⁻¹, temperature = 344 K.
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Amount of substance = (158000 × 0.0016) ÷ (8.31 × 344) = 0.0884 mol. -
Equations, concentration and reacting quantities
Convert a volume of 724 cm³ into dm³.
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Volume = 724 ÷ 1000 = 0.724 dm³.
Paper 2, Paper 3
Organic Chemistry I
202 questions in the guide, across 14 subtopics. More from this topic
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Formulae, homologous series and functional groups
What is a general formula?
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An algebraic formula that can represent any member of a homologous series. -
IUPAC nomenclature
State the IUPAC prefix for a ten-carbon chain.
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Dec- -
Stereoisomerism and E/Z nomenclature
In E/Z nomenclature, what does the Z isomer indicate about the positions of higher priority groups?
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The higher priority groups are on the same side of the double bond (zusammen means together).
Paper 2, Paper 3
Modern Analytical Techniques I
45 questions in the guide, across 3 subtopics. More from this topic
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Mass spectrometry
In a mass spectrum, a loss of 15 mass units from the molecular ion indicates the loss of which group?
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CH₃ (a methyl group). -
Mass spectrometry
What does the term m/z represent in mass spectrometry?
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The mass-to-charge ratio of an ion. -
Infrared spectroscopy and the characteristic absorptions
What type of peak does C=C stretching in alkenes produce in an IR spectrum?
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A characteristic absorption peak at a specific wavenumber range.
Paper 1, Paper 3
Energetics I
39 questions in the guide, across 2 subtopics. More from this topic
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Enthalpy changes, standard definitions and calorimetry
Define the standard enthalpy change of reaction.
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The enthalpy change when the molar amounts shown in the equation react under standard conditions, with all substances in their standard states. -
Enthalpy changes, standard definitions and calorimetry
What value of the specific heat capacity of water is normally used?
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4.18 J per gram per kelvin. -
Hess's law and bond enthalpies
Define bond enthalpy.
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The energy required to break one mole of a specified covalent bond with all species in the gaseous state.
Paper 2, Paper 3
Kinetics I
32 questions in the guide, across 3 subtopics. More from this topic
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Collision theory and factors affecting rate
What does activation energy mean?
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The minimum energy that colliding particles must have for a reaction to take place. -
Collision theory and factors affecting rate
Why does increasing the surface area of a solid reactant increase the rate?
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More reactant particles are exposed at the surface, so collisions with them are more frequent. -
Maxwell-Boltzmann distribution and temperature
What does the total area under a Maxwell-Boltzmann curve represent?
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The total number of particles.
Paper 1, Paper 3
Equilibrium I
24 questions in the guide, across 2 subtopics. More from this topic
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Dynamic equilibrium and Le Chatelier's principle
What type of system is required for a reaction to reach equilibrium?
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A closed system, where no reactants or products can enter or leave. -
Dynamic equilibrium and Le Chatelier's principle
In which direction does an increase in total pressure shift a gaseous equilibrium?
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Towards the side with fewer moles of gas. -
The equilibrium constant Kc
What concentrations are used in the Kc expression?
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The concentrations of the species at equilibrium.
Paper 1, Paper 3
Equilibrium II
23 questions in the guide, across 2 subtopics. More from this topic
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Partial pressures and Kp
What do the mole fractions of all the gases in a mixture add up to?
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1. -
Partial pressures and Kp
Which species are included in a Kp expression?
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Only gases; pure solids and pure liquids are omitted. -
Calculating Kp and the effect of conditions
How is the total number of moles of gas used when calculating partial pressures?
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It is used to find each mole fraction before multiplying by the total pressure.
Paper 1, Paper 3
Acid-Base Equilibria
73 questions in the guide, across 5 subtopics. More from this topic
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Bronsted-Lowry acids and bases, and the pH scale
What forms when an acid donates a proton?
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The acid forms its conjugate base. -
Bronsted-Lowry acids and bases, and the pH scale
Once hydrogen ion concentration is known, how is pH calculated?
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pH = −log₁₀[H⁺] -
Strong and weak acids, Ka and Kw
What assumption is made about the equilibrium concentration of a weak acid HA when the degree of dissociation is small?
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The equilibrium concentration of HA approximately equals the initial concentration of the acid.
Paper 1, Paper 3
Energetics II
70 questions in the guide, across 4 subtopics. More from this topic
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Lattice energy
When calculating the enthalpy change of solution, why must you consider more than one enthalpy of hydration value?
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Separate enthalpy of hydration values exist for cations and anions, and both must be considered when calculating the overall enthalpy change of solution. -
Lattice energy
Why is the enthalpy of hydration of Al³⁺ more exothermic than that of Na⁺?
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Al³⁺ has a higher charge and smaller radius, giving it a much higher charge density, which results in stronger ion-dipole interactions with water. -
Born-Haber cycles and electron affinity
State the Hess's law relationship used to find lattice energy from a Born-Haber cycle.
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The enthalpy of formation equals the sum of the atomisation enthalpies, the ionisation energies and the electron affinities, plus the lattice energy. Rearranging gives the lattice energy.
Paper 1, Paper 3
Redox II
62 questions in the guide, across 4 subtopics. More from this topic
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Standard electrode potentials and the hydrogen electrode
What is meant by the standard electrode potential of a half-cell?
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The voltage of that half-cell measured relative to the standard hydrogen electrode under standard conditions. -
Standard electrode potentials and the hydrogen electrode
Why is platinum used in the standard hydrogen electrode?
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It is inert and provides a surface for the reaction and a means of electrical contact. -
Electrochemical cells, emf and cell diagrams
At which electrode does reduction occur?
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At the positive electrode.
Paper 1, Paper 3
Transition Metals
123 questions in the guide, across 9 subtopics. More from this topic
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Electron configuration and what makes a transition metal
State the electronic configuration of copper.
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[Ar] 3d¹⁰ 4s¹ -
Complex ions, ligands and the colour of transition metal ions
State a characteristic property of transition metal ions in solution.
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They form coloured ions in solution. -
Coordination number, monodentate ligands and the shapes of complexes
Explain why ammonia acts as a monodentate ligand.
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Ammonia has a lone pair on the nitrogen atom that can form one dative bond to a metal ion.
Paper 2, Paper 3
Kinetics II
74 questions in the guide, across 4 subtopics. More from this topic
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Rate equations, orders and the rate constant
What is the rate constant, k?
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The proportionality constant in the rate equation linking rate to the reactant concentrations. -
Rate equations, orders and the rate constant
What are the units of the rate constant for a first-order reaction overall?
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s⁻¹. -
Determining orders from experiments
What is the shape of a rate-concentration graph for a first-order reaction?
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A straight line through the origin.
Paper 2, Paper 3
Organic Chemistry II
113 questions in the guide, across 8 subtopics. More from this topic
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Chirality
In an Sₙ1 reaction of a chiral halogenoalkane, what happens in the first step?
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The chiral halogenoalkane loses the halide ion to form a carbocation -
Aldehydes, ketones and their oxidation
Why is the carbonyl carbon open to attack by a nucleophile?
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Oxygen is considerably more electronegative than carbon, so the C=O bond is strongly polarised and the carbon carries a partial positive charge that attracts an electron-rich species. -
Reduction and nucleophilic addition of HCN
How is the reducing agent written in equations for these reactions?
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As [H], so the reduction of propanone is written CH₃COCH₃ + 2[H] → CH₃CH(OH)CH₃.
Paper 2, Paper 3
Organic Chemistry III
129 questions in the guide, across 10 subtopics. More from this topic
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The structure of benzene and the evidence for it
What enthalpy of hydrogenation would be predicted for cyclohexatriene based on the Kekulé structure?
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Approximately three times the enthalpy of hydrogenation of cyclohexene. -
Electrophilic substitution of benzene
What reagents are required for the nitration of benzene?
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A mixture of concentrated nitric acid and concentrated sulfuric acid. -
Nitration, halogenation, Friedel-Crafts and phenol
In Friedel-Crafts alkylation, how is the carbocation electrophile generated?
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Aluminium chloride accepts a lone pair from the halogen of the halogenoalkane, generating a carbocation.
Paper 2, Paper 3
Modern Analytical Techniques II
51 questions in the guide, across 4 subtopics. More from this topic
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Carbon-13 and proton NMR
How can you determine the number of distinct carbon environments in a molecule from its carbon-13 NMR spectrum?
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The number of peaks in the spectrum equals the number of distinct carbon environments in the molecule. -
Carbon-13 and proton NMR
Why do protons attached to different functional groups appear at different chemical shift values in proton NMR?
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Because different chemical shift values correspond to protons in different chemical environments. -
Splitting, integration and the reference standard
How many equivalent neighbouring protons on adjacent carbons produce a triplet in proton NMR?
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Two equivalent neighbouring protons on adjacent carbons.
Edexcel A-Level Chemistry Active Recall Guide
The other 1,477 questions, with the answers printed after each section.