Cambridge Past Paper Questions
Browse 23,045questions from 25 years of O-Level & A-Level exams. Click any question to practice.
The following half reactions occur when potassium iodate(V), KIO3, in hydrochloric acid solution oxidises iodine to ICl2⁻. IO3⁻ + 2Cl⁻ + 6H⁺ + 4e⁻ ...
Use of the Data Booklet is relevant to this question. In which set do all species contain the same number of electrons?
An autocatalytic reaction is a reaction in which one of the products catalyses the reaction. Which curve was obtained if the rate of reaction was p...
The diagrams below show the Boltzmann distribution for air at two temperatures. The solid line represents the distribution at –20 °C. The dotted li...
Which stage in the free radical substitution of methane by chlorine will have the lowest activation energy?
Use of the Data Booklet is relevant to this question. The approximate percentage composition of the atmosphere on four different planets is given i...
Nitrogen reacts with hydrogen to produce ammonia. N2(g) + 3H2(g) ⇌ 2NH3(g) A mixture of 2.00 mol of nitrogen, 6.00 mol of hydrogen, and 2.40 mol of...
Use of the Data Booklet is relevant to this question. Which sodium compound contains 74.2% by mass of sodium?
Use of the Data Booklet is relevant to this question. A student carried out an experiment to determine the enthalpy change for the combustion of me...
Strontium metal can be obtained by the electrolysis of molten strontium bromide, SrBr2, using the apparatus shown in the diagram. [Diagram of appar...
A metal, X, reacts with water to produce a colourless solution which gives a white precipitate when mixed with aqueous sulfuric acid. What is metal X?
Which property increases in value going down Group II?
Which row correctly identifies the uses of some of the compounds of Group II metals? [Table showing uses in kilns and agriculture for various Group...
Solid potassium halides react with concentrated sulfuric acid, according to the following equations. reaction 1 2KCl + H2SO4 → K2SO4 + 2HCl reactio...
Transition metals and their compounds are used as catalysts. Which row is correct? [Table showing transition metal present in the catalyst used in ...
Consecutive elements X, Y and Z are in the third period of the Periodic Table. Element Y has the highest first ionisation energy and the lowest mel...
A new industrial preparation of ethyl ethanoate has been developed using cheap sources of ethanol. [Reaction scheme: CH3CH2OH → CH3CHO → CH3CH(OH)O...
Which reaction will give the best yield of 1-chloropropane?
The compound 'leaf alcohol' is partly responsible for the smell of new-mown grass. CH3CH2CH=CHCH2CH2OH leaf alcohol What will be formed when ‘leaf ...
A carbanion is an organic ion in which a carbon atom has a negative charge. A carbocation is an organic ion in which a carbon atom has a positive c...
What are the only structures formed when butan-2-ol is heated with concentrated H2SO4?
How many moles of hydrogen, H2, are evolved when an excess of sodium metal is added to one mole of citric acid? [Structure of citric acid: CO2H-C(O...
How many of the compounds shown will react with aqueous sodium hydroxide to form the sodium salt of a carboxylic acid? The compounds are: CH3COOCH2...
Which types of bond breakage and bond formation occur in the addition polymerisation of alkenes?
X is a particle with 18 electrons and 20 neutrons. What could be the symbol of X? 1. ³⁸₁₈Ar 2. ⁴⁰₂₀Ca²⁺ 3. ³⁹₁₉K⁺
Use of the Data Booklet is relevant to this question. Carbon and nitrogen are adjacent in the Periodic Table. Which properties do they both have? 1...
What are necessary properties of a dynamic equilibrium? 1. Equal amounts of reactants and products are present. 2. Concentrations of reactants and ...
If N2O4 gas is placed in a sealed vessel the following equilibrium is established. N2O4(g) ⇌ 2NO2(g) The forward reaction is endothermic. What happ...
Which types of bonding are present in ammonium carbonate, (NH4)2CO3? 1. ionic 2. covalent 3. co-ordinate (dative covalent)
Sulfur dioxide and sulfites are used in food preservation. Why are they used for this purpose? 1. They are reducing agents which slow down the oxid...
The organic compound X gives a precipitate when warmed with aqueous silver nitrate. This precipitate dissolves when concentrated aqueous ammonia is...
An organic compound Y, molecular formula C6H14O, may be oxidised to compound Z, molecular formula C6H12O2. What could be the structural formula of ...
Which reactions can be used to make an alcohol in the laboratory? 1. hydrolysis of a bromoalkane with NaOH(aq) 2. reduction of a ketone with NaBH4 ...
The compounds below are treated with hydrogen cyanide. Which compounds react and produce a molecule containing a chiral centre? 1. butanal 2. penta...
Which solid-line curve most accurately represents the distribution of molecular energies in a gas at 500K if the dotted-line curve represents the c...
In which reaction does hydrogen behave as an oxidising agent?
Ethanol is increasingly being used as a fuel for cars. The standard enthalpy change of formation of carbon dioxide is –393 kJ mol⁻¹. The standard e...
Two glass vessels M and N are connected by a closed valve. [Figure: Diagram showing two connected vessels M and N, separated by a valve.] M contain...
The table shows the physical properties of four substances. Which substance could be hydrogen chloride? [Table with columns: melting point /°C, ele...
Aluminium carbide, Al₄C₃, reacts readily with aqueous sodium hydroxide. The two products of the reaction are NaAlO₂ and a hydrocarbon. Water molecu...
In an experiment to calculate the enthalpy change of combustion of a fuel, 1.5g (0.0326 mol) of the fuel was used to heat 200 g of water. The tempe...
The reaction pathway diagram below illustrates the energies of the reactants, the products and the transition state of a reaction. [Figure showing ...
Methylpropan-1-ol and butan-1-ol are structural isomers. Methylpropan-1-ol has a lower boiling point. Which statement explains why the boiling poin...
Which row correctly describes the electrodes used in the electrolysis cell for the production of aluminium? [Table with columns: anode, cathode]
For which equation is the enthalpy change correctly described as an enthalpy change of formation?
Element X, in Period 3, has the following properties. • Its oxide has a giant structure. • It forms covalent bonds with chlorine. • Its oxide will ...
Which property is not associated with the element sodium?
Use of the Data Booklet is relevant to this question. Sir Humphrey Davy discovered boron, calcium, magnesium and sodium. Which of these elements ha...
Use of the Data Booklet is relevant to this question. A sample of potassium oxide, K₂O, is dissolved in 250cm³ of distilled water. 25.0cm³ of this ...
Chlorine gas reacts with cold aqueous sodium hydroxide. It can also react with hot aqueous sodium hydroxide. What are the oxidation numbers of chlo...