Cambridge Past Paper Questions
Browse 23,045questions from 25 years of O-Level & A-Level exams. Click any question to practice.
The hydrolysis of urea, (NH₂)₂CO, Mr = 60, is shown by the equation. The reaction is catalysed by the enzyme urease, when present in low concentrat...
The diagram shows a Boltzmann distribution of the energies of gaseous molecules and the activation energies, Ea, of a reaction with and without a c...
In this question it should be assumed that (NH4)2CO3.H2O(s) dissolves in water without causing an increase in volume. Which mass of (NH4)2CO3.H2O(s...
The graph shows the successive ionisation energies of element X and element Y. Both elements are in Period 3. [Figure 3.1]
Which statement about the electrons in a ground state carbon atom is correct?
In this question you should assume the vapour behaves as an ideal gas. 0.175g of a volatile liquid produces a vapour of volume 4.50 × 10⁻⁵m³ at 100...
Which reaction is endothermic?
Which equation correctly represents the standard enthalpy change of atomisation of the given element?
(NH₄)₂Cr₂O₇ decomposes when heated. (NH₄)₂Cr₂O₇ → N₂ + 4H₂O + Cr₂O₃ Which element is oxidised and which element is reduced?
When lead(II) sulfide, PbS, is heated in air, sulfur dioxide and lead(II) oxide are formed. What is the equation for the reaction between PbS and o...
The decomposition of SO₃(g) is a dynamic equilibrium. 2SO₃(g) ⇌ 2SO₂(g) + O₂(g) What happens when the pressure of the system is increased?
Hydrated aluminium ions undergo the following reaction. [Al(H₂O)₆]³⁺(aq) + H₂O(l) ⇌ [Al(H₂O)₅OH]²⁺(aq) + H₃O⁺(aq) Which statement about this reacti...
Which diagram correctly shows the electronegativity of the elements Na, Mg, Al and Si plotted against their first ionisation energies? [Figure 12.1]
Which statement about the compounds of Group 2 elements magnesium to barium is correct?
When equal volumes of saturated solutions of barium hydroxide and calcium hydroxide are mixed, a white precipitate, Y, forms. The mixture is filter...
The properties of chlorine, bromine and their compounds are compared. Which property is smaller for chlorine than for bromine?
Solid sodium iodide reacts with concentrated sulfuric acid to form more than one product that contains sulfur. What is the lowest oxidation number ...
Which emission from an internal combustion engine contributes to the erosion of marble statues?
Ammonia, carbon dioxide and water react together to form ammonium carbonate. Which statement about this reaction is correct?
The diagram shows the skeletal formula of phenazine. [Figure 21.1] What is the empirical formula of phenazine?
An organic compound X reacts with hot, concentrated acidified potassium manganate(VII) solution to give a single carbon-containing product. What co...
1-chloro-2-methylbutane reacts with sodium cyanide in ethanol in a nucleophilic substitution reaction. What is the most likely intermediate or tran...
Propan-1-ol can be reacted with acidified potassium dichromate(VI) to form propanoic acid, reaction 1, or propanal, reaction 2. [Figure 24.1] How c...
What is the smallest amount of oxygen molecules needed for the complete combustion of 40.0 g of methanol?
The diagram shows the structure of Y. [Figure 27.1] Two suggestions are made about Y. 1 Y can be oxidised by hot, acidified dichromate(VI) ions. 2 ...
Esters can be prepared by the reaction of a carboxylic acid with an alcohol in the presence of concentrated sulfuric acid. Which row gives the corr...
Compound Q can be hydrolysed by HCl(aq). The two products of this hydrolysis have the same empirical formula. What could Q be?
Substance T was analysed and found to contain 62.07% carbon, 10.34% hydrogen and 27.59% oxygen. The infra-red spectrum of substance T is shown. [Fi...
Which gaseous molecules are polar? 1 ammonia 2 hydrogen sulfide 3 boron trifluoride
A carbon monoxide molecule, CO, has three bonds between the carbon atom and the oxygen atom. Which features are present in one CO molecule? 1 two l...
Carbon can exist as allotropes which include graphite, diamond and a fullerene. Which statements are correct? 1 All three allotropes contain covale...
The reaction pathway diagram for a reversible reaction is shown. [Figure 34.1] Which statements are correct? 1 The enthalpy change for the backward...
Silicon forms a tetrachloride, SiCl₄. Which statements are correct? 1 In SiCl₄, the Si is δ+ and each Cl is δ-. 2 SiCl₄ is a liquid at room tempera...
Which statements about ammonia are correct? 1 An ammonia molecule has three bond pairs and one lone pair of electrons. 2 When ammonia is bubbled in...
Following fractional distillation of crude oil, which processes can be used to produce propene from larger hydrocarbon molecules? 1 cracking 2 redu...
Bromoethane undergoes nucleophilic substitution reactions. Which statements are correct? 1 Bromoethane reacts with aqueous NaOH to make ethanol. 2 ...
Which reagents, when used in excess, can convert Y into Z? [Figure 39.1] 1 Na 2 Na₂CO₃ 3 NaOH
Each of the compounds below is treated separately with an excess of NaBH₄. The product of each reaction is then heated with an excess of concentrat...
Answer all the questions in the spaces provided. 1 (a) Chlorine can be prepared using the following reaction. MnO2(s) + 4HCl(aq) → MnCl2(aq) + 2H2O...
2 (a) Complete the table to give details of the type of bonding and structure shown by some of the oxides of Period 3 elements. [Figure 2.1]
3 Crude oil is a natural source of hydrocarbons that are used as fuels. (a) Hydrocarbons with low relative molecular mass, Mr, are used as fuels in...
4 (CH3)3CCHO is used in the synthesis of some antibiotics. (a) (i) Give the name of (CH3)3CCHO. (ii) State the hybridisation of the carbon atom lab...
In the Periodic Table, the p block contains elements whose outer electrons are found in the p subshell.
Oxygen is the most abundant element in the Earth's crust. It reacts with other elements to form stable compounds, ions and molecules.
A series of reactions for phosphorus and its compounds is shown. P ---excess Cl2 reaction 1---> PCl5 ---H₂O reaction 2---> H3PO4 ---NH3 reaction 3-...
Prenol is a naturally occurring organic molecule found in many fruits. It contains both an alkene and an alcohol functional group. [Figure: structu...
Chlorine can be prepared using the following reaction. MnO₂(s) + 4HCl(aq) → MnCl₂(aq) + 2H₂O(l) + Cl₂(g)
(a) Complete the table to give details of the type of bonding and structure shown by some of the oxides of Period 3 elements. | | Na₂O | MgO | Al₂O...
Crude oil is a natural source of hydrocarbons that are used as fuels.
(CH₃)₃CCHO is used in the synthesis of some antibiotics.