Cambridge Past Paper Questions
Browse 23,045questions from 25 years of O-Level & A-Level exams. Click any question to practice.
What are the same for a pair of optical isomers?
Which statements about the photochemical chlorination of ethane are correct?
The compound shown is a hormone produced during pregnancy to suppress ovulation. [Figure 40.1] Which reagents would give positive results with this...
During the electrolysis of molten aluminium oxide to produce aluminium, using carbon electrodes, two consecutive reactions occur at the anode, each...
Equations involving four enthalpy changes are shown. Na(g) → Na⁺(g) + e⁻ ΔΗ = W Na(g) → Na²⁺(g) + 2e⁻ ΔΗ = X Na(s) → Na(g) ΔΗ = Y Na(s) → Na²⁺(g) +...
Which ion has more electrons than protons and more protons than neutrons? [H = ¹H ; D = ²H ; O = ¹⁶O]
Which factor can affect the value of the activation energy of a reaction?
The diagram shows the Maxwell-Boltzmann energy distribution curves for molecules of a sample of a gas at two different temperatures. Which letter o...
Which pair of elements has chemical bonds of the same type between their atoms in the solid state?
Ethanol has a boiling point of 78°C. At 101 kPa and 79°C ethanol vapour does not perfectly obey the gas equation pV = nRT. What is the reason for t...
The reaction between sulfur dioxide and oxygen is a dynamic equilibrium. 2SO₂(g) + O₂(g) ⇌ 2SO₃(g) What happens when the pressure of the system is ...
Dicarbon monoxide, C₂O, is found in dust clouds in space. Analysis of it shows that the sequence of atoms in this molecule is C–C–O. All bonds are ...
Use of the Data Booklet is relevant to this question. A student mixed 25 cm³ of 0.10 moldm⁻³ sodium hydroxide solution with 25 cm³ of 0.10 moldm⁻³ ...
Which energy change corresponds to the enthalpy change of atomisation of hydrogen at 298 K?
Propanone has molecular formula C₃H₆O. The enthalpy change of combustion of hydrogen is –286 kJ mol⁻¹. The enthalpy change of combustion of carbon ...
Use of the Data Booklet is relevant to this question. Magnesium nitrate, Mg(NO₃)₂, will decompose when heated to give a white solid and a mixture o...
In which row of the table are all statements comparing the compounds of calcium and barium correct? [Figure 14.1]
Many modern cars are fitted with halogen lamps. When such lamps are first switched on, a distinct purple colour can be seen. Which species is respo...
The trends in three physical properties of the elements Na, Mg, Al, Si, P and S are shown in the graphs. [Figure 16.1] Which physical property is n...
Which statement about ammonia is completely correct?
What happens when bromine solution is added to a solution of sodium iodide?
The halogens exist as diatomic molecules, X₂. The boiling points of the Group VII elements increase as the group is descended from chlorine to iodi...
The compound hex-3-en-1-ol, P, has a strong 'leafy' smell of newly cut grass and is used in perfumery. CH₃CH₂CH=CHCH₂CH₂OH P What is produced when ...
Sorbic acid is used as a food preservative because it kills fungi and moulds. [Figure 21.1] Sorbic acid will react with • hydrogen in the presence ...
Aqueous sodium hydroxide reacts with 2-bromo-2-methylpropane to give 2-methylpropan-2-ol. The reaction proceeds by an Sɴ1 mechanism. How should the...
Compound Y can be hydrolysed by warm aqueous silver nitrate to form a precipitate that is soluble in dilute aqueous ammonia. Compound Y can undergo...
The compound shown is menthol, a naturally-occurring alcohol found in peppermint oil. [Figure 25.1] When menthol is heated with concentrated sulfur...
Use of the Data Booklet is relevant to this question. Which volume of oxygen measured at room temperature and pressure is needed for complete combu...
Which carbonyl compound reacts with hydrogen cyanide to form a product that has no chiral carbon atom?
How many of the following compounds produce a carboxylic acid on heating under reflux with hot acidified K₂Cr₂O₇? CH₃CH₂CHO CH₃COCH₃ CH₃CH₂CH₂OH CH...
Compound Y has Mᵣ of 88. It does not fizz when added to a solution of sodium hydrogencarbonate. It can be hydrolysed by dilute sulfuric acid to pro...
Polymerisation of ethene gives poly(ethene). How does the carbon–carbon bond in poly(ethene) compare with that in ethene?
Use of the Data Booklet is relevant to this question. In which pairs do both species have the same number of unpaired p electrons? 1 Al²⁻ and O⁺ 2 ...
The diagram shows the reaction pathway for a reversible reaction. [Figure 32.1] Which statements are correct? 1 The enthalpy change for the backwar...
Which substances contain delocalised electrons? 1 cyclohexene 2 graphite 3 sodium
Solids W, X, Y and Z are compounds of two different Group II metals. Some of their applications are described below. Compound W is used as a refrac...
Which properties increase in the sequence hydrogen chloride, hydrogen bromide and hydrogen iodide? 1 thermal stability 2 bond length 3 ease of oxid...
Sulfur dioxide is an atmospheric pollutant that causes acid rain. One of the reactions in this process is the oxidation of sulfur dioxide to sulfur...
Which are properties of fluoroalkanes? 1 They are less reactive than the corresponding chloroalkanes. 2 They are non-flammable. 3 The C–F bond is s...
What can be produced when an aqueous solution of butan-2-ol is oxidised under suitable conditions? 1 butanone 2 butanoic acid 3 butanal
The Mᵣ of compound X is 72. The composition by mass of X is 66.7% carbon, 11.1% hydrogen and 22.2% oxygen. X gives an orange precipitate with 2,4-d...
An organic compound, Z, will react with calcium metal to produce a salt with the empirical formula CaC₄H₆O₄. What could be the identity of Z? 1 eth...
The diagram shows a Boltzmann distribution of molecular energies for a gaseous mixture. The distribution has a peak, labelled P on the diagram. [Fi...
Substances X, Y and Z are all solids. Some of their physical properties are given in the table. [Figure 2.1] What type of lattice could each substa...
The enthalpy change of formation of carbon dioxide is –394 kJ mol⁻¹. The enthalpy change of formation of water is –286 kJ mol⁻¹. The enthalpy chang...
Hydrogen and carbon dioxide gases are mixed in equal molar amounts at 800K. A reversible reaction takes place. H2(g) + CO2(g) ⇌ H2O(g) + CO(g) At e...
In the diagram, curve X was obtained by observing the decomposition of 100 cm³ of 1.0 mol dm⁻³ hydrogen peroxide, catalysed by manganese(IV) oxide....
In which reaction is the species in bold acting as an oxidising agent?
The formation of hydrogen and ethyne, C2H2, from methane reaches dynamic equilibrium. 2CH4(g) ⇌ 3H2(g) + C2H2(g) What are the units of Kp?
Which equation represents the standard enthalpy change of formation of ethanol, C2H5OH?