Cambridge Past Paper Questions
Browse 23,045questions from 25 years of O-Level & A-Level exams. Click any question to practice.
P, Q and R all have the molecular formula C₃H₆O. They are all structural isomers of each other. P and Q each contain an oxygen atom bonded directly...
The composition of atoms and ions can be determined from knowledge of atomic number, nucleon number and charge.
Nitrogen gas, N₂, is very unreactive.
The hydrogen halides, HCl, HBr and HI, can undergo thermal decomposition. In a sealed container an equilibrium is established according to the equa...
The halogens, chlorine, bromine and iodine, and their compounds, show a variety of similarities and trends in their physical and chemical properties.
Sulfur trioxide, SO3, is manufactured from sulfur dioxide and oxygen by the Contact process. 2SO2(g) + O2(g) ⇌ 2SO3(g) ΔH = –196.0 kJ mol⁻¹
A, B and C all have the formula C₄H₈. They all decolourise bromine and are structural isomers of each other.
In this experiment you will determine the relative formula mass of a copper salt by titration. A solution of the copper salt reacts with excess aci...
Malachite is a basic form of copper carbonate in which copper hydroxide is also present. The accepted chemical formula of malachite is CuCO3.Cu(OH)...
HA is an organic acid where A¯ is the anion. You will determine the relative formula mass, M., of HA by titration with sodium hydroxide of known co...
You are to determine the enthalpy change of neutralisation for a different acid from that used in Question 1. The acid is represented by HB where B...
Sodium hydrogencarbonate, NaHCO3, is used as baking soda in cooking. Baking soda may also contain small amounts of other chemicals. In this experim...
When baking soda is heated, carbon dioxide is produced. In this experiment you will investigate the reaction taking place when the sodium hydrogenc...
The table lists the standard enthalpy changes of formation, ΔΗ, for some compounds and aqueous ions. ``` species ΔH_f/kJ mol⁻¹ Ba²⁺(aq) ...
One atom of each of the four elements H, C, N and O can bond together in different ways. Two examples are molecules of cyanic acid, HOCN, and isocy...
Bubbling air through different aqueous mixtures of CoCl₂, NH₄Cl and NH₃ produces various complex ions with the general formula [Co(NH₃)₆₋nClₙ]³⁻ⁿ.
Carvone occurs in spearmint and a stereoisomer of carvone occurs in caraway seeds. Treating either isomer with hydrogen over a nickel catalyst prod...
Compounds J, K, L and M are isomers of each other with the molecular formula C₉H₁₁NO. All four isomers contain a benzene ring. Two of the isomers c...
The reaction between 1-chloro-1-phenylethane and hydroxide ions to produce 1-phenylethanol is: C₆H₅CH(Cl)CH₃ + OH⁻ → C₆H₅CH(OH)CH₃ + Cl⁻ 1-chloro-1...
A number of isomers with the formula Cr(H2O)6Cl3 exist. Their general formula is [Cr(H2O)6-nCln]Cl3-n.nH2O. Each isomer contains a six co-ordinated...
1,2-diaminoethane, en, H2NCH2CH2NH2, is a bidentate ligand.
The table lists some organic acids and their pKa values. acid formula pKa ethanoic acid CH3CO₂H 4.76 chloroethanoic acid CICH₂CO₂H 2.86 aminoet...
Compounds W, X, Y and Z are isomers of each other with the molecular formula C｡H,CIO. All four isomers contain a benzene ring. Only one of the isom...
The amino acid tyrosine can be synthesised from phenol by the route shown. OH step 1 CHO step 2 CN HO HO phenol HO step 3 NH2 Cl OH step 5 s...
The table lists the standard enthalpy changes of formation, ΔH, for some compounds and aqueous ions. | species | ΔHᶠ/kJ mol⁻¹ | |------------|-...
The pain of muscle strains and swellings can be eased by using heat packs. As a source of heat, some heat packs use the energy released when anhydr...
Sucrose is a sugar. The concentration of a solution of sucrose can be measured by the optical rotation, α, of a sucrose solution. The more concentr...
In 1804 the chemist John Dalton put forward the following idea. It is sometimes called 'Dalton's Law'. 'When two elements combine with each other ...
When light passes through solutions of chemical compounds some of the light may be absorbed. The quantity of light absorbed is called the absorbanc...
Which feature is present in both ethene and poly(ethene)?
The electronic configuration of an atom of sulfur is 1s²2s²2p⁶3s²3p⁴. How many valence shell and unpaired electrons are present in one sulfur atom?...
In which pair does the second substance have a lower boiling point than the first substance?
Compound J burns in excess oxygen to give carbon dioxide and water only. When a 3.00 g sample of compound J is burnt in excess oxygen, 4.40 g of ca...
The gases X and Y react to form Z. X(g) + Y(g) ⇌ Z(g) An equilibrium mixture of these three gases is compressed at constant temperature. What will ...
Which gas is likely to deviate most from ideal gas behaviour?
The enthalpy change of reaction 1 is –114 kJ mol⁻¹. 2NaOH(aq) + H2SO4(aq) → Na2SO4(aq) + 2H2O(l) reaction 1 By using this information, what is the ...
Sulfur reacts with concentrated nitric acid in a redox reaction. S + 4HNO3 → SO2 + 4NO2 + 2H2O What are the changes in oxidation number of sulfur a...
Materials can be classified by their chemical structures. Four common types of structure are metallic, ionic, simple molecular and giant molecular....
In a particular reversible reaction the yield of product is increased • if the temperature is increased; • if the pressure is decreased. Which equa...
A chemical company used a catalyst in a chemical process. The company has now decided not to use the catalyst but to increase the temperature so th...
Which oxide does not react with cold, dilute sodium hydroxide to produce a salt?
The graphs show trends in four physical properties of elements in Period 3, excluding argon. Which graph has electronegativity on the y-axis? [Grap...
In this question, X represents an atom of chlorine, bromine or iodine. Which explanation for the variation in volatility down Group 17 is correct?
To manufacture cement, 1000 million tonnes of limestone are decomposed each year. To manufacture lime for agriculture, 200 million tonnes of limest...
When concentrated sulfuric acid is added to solid sodium bromide, bromine gas is produced, along with a number of other products. However when conc...
The dative covalent bond can be represented by an arrow, →. The arrow points towards the atom receiving the lone pair. Which diagram of an ammonium...