Cambridge & Pearson Edexcel Past Paper Questions
Browse 35,704 questions from Cambridge O-Level & A-Level and Pearson Edexcel IGCSE & IAL exams. Click any question to practice.
A reaction pathway diagram is shown. [Figure showing reaction pathway diagram with two humps] Which reactions would have such a profile? 1 (CH₃)₃CB...
In the Haber process for the manufacture of ammonia, why is the heterogeneous catalyst iron in a finely divided state?
The following equations the letters W, X, Y and Z all represent whole numbers. When correctly balanced, which equation requires one of letters W, X...
Use of the Data Booklet is relevant to this question. From which particle is the removal of an electron the most difficult?
Use of the Data Booklet is relevant to this question. 560 kg of nitrogen and 120 kg of hydrogen are pressurised, heated and passed over an iron cat...
The presence of dipoles helps to explain why the element Br2 and the compound CHCl3 exist as liquids at room temperature. Which types of dipole are...
Three compounds have the physical properties shown in the table. [Figure for table of properties of P, Q, R] What might be the identities of P, Q a...
For the equilibrium 2SO2(g) + O2(g) ⇌ 2SO3(g), what will change the value of Kp?
Which pollutant, present in the exhaust fumes of an internal combustion engine, has an element in the +2 oxidation state and an odd number of elect...
The use of sucrose in food processing depends in part on osmotic pressure, symbol Π. In dilute solution, Π varies with concentration in a similar w...
Hess’s Law can be used to calculate the average C–H bond energy in methane. ΔH°at = standard enthalpy change of atomisation ΔH°f = standard enthalp...
The amount of titanium dioxide in an ore can be determined by using the following reaction. 3TiO2 + 4BrF3 → 3TiF4 + 2Br2 + 3O2 Which element increa...
For the reaction W(aq) + 2X(aq) ⇌ 2Y(aq) + 3Z(aq) what are the correct units for the equilibrium constant Kc?
Methyl mercaptan, CH3SH, has a foul smell and is often used to impart a smell to natural gas. What will be formed when CH3SH is burned in an excess...
Nitrogenous fertilisers are used extensively in modern farming. If rainwater washes excess fertiliser into a nearby lake, a process called eutrophi...
Chlorine can be manufactured from brine in a diaphragm cell. Which row represents the correct electrodes?
Sodium iodide reacts with concentrated sulfuric acid. The equation which represents one of the reactions that takes place is shown. 8NaI + 9H2SO4 →...
The standard enthalpy changes of formation of HCl and HI are –92 kJ mol⁻¹ and +26 kJ mol⁻¹ respectively. Which statement is most important in expla...
Lime mortar is made from quicklime, water and sand. Over a period of time, lime mortar changes into a much harder form. Both fresh and old lime mor...
Ar, Ca²⁺ and K⁺, contain the same number of electrons. In which order do their radii increase?
Bromine and propene undergo an addition reaction. Which is a property of the product?
Buta-1,3-diene is currently obtained from fossil fuel sources. In future it may be obtained from ethanol, which can be produced from non-food agric...
Use of the Data Booklet is relevant to this question. Which bond in the structure below has the lowest bond energy? [Figure for molecule structure]
Ethanal, CH3CHO, can be reduced using NaBH4 in aqueous ethanol. This is a nucleophilic addition reaction. What could be the first step of this mech...
In a sequence of reactions, ethanal is converted into a compound H. [Figure for reaction scheme] What could H be?
What is involved in the mechanism of the reaction between aqueous sodium hydroxide and 2-bromo-2-methylbutane?
Use of the Data Booklet is relevant to this question. 2.30 g of ethanol were mixed with aqueous acidified potassium dichromate(VI). The desired pro...
The molecule shown is optically active. [Figure for molecule structure] How many chiral carbon atoms are present in this molecule?
Which reagent could best be used to distinguish between cyclohexene and cyclohexanol?
Compound X, molecular formula C4H8, undergoes the following reactions. [Figure for reaction scheme] What is the formula of compound Z?
How many of the isomeric alcohols with the formula C4H9OH will produce an alkene that has cis and trans isomers, on treatment with conc. H2SO4?
Which statements about bond angles are correct? 1 The bond angle in SO2 is smaller than the bond angle in CO2. 2 The bond angle in H2O is smaller t...
An energy profile diagram is shown. [Figure for energy profile diagram] What do the labels on the diagram represent? 1 W = ΔH of the forward reacti...
Which are assumptions of the kinetic theory of gases and hence of the ideal gas equation, PV = nRT? 1 Molecules move without interacting with one a...
Use of the Data Booklet is relevant to this question. Which properties would be expected for radium, ⁸⁸Ra, or its compounds? 1 Radium carbonate wou...
When a firework is lit, a fuel and an oxidising agent react together. In one such firework, magnesium is the fuel and barium nitrate is the oxidisi...
Compound X has molecular formula C4H10O. Separate samples of X are tested with three different reagents. Which results could not be obtained?
Y is an organic compound. Y gives a precipitate with aqueous silver nitrate. All of this precipitate dissolves when concentrated aqueous ammonia is...
Which compounds will produce ethanoic acid when boiled under reflux with dilute alkali followed by acidification? 1 CH3CH2Cl 2 CH3CO2CH3 3 CH3CN
Which pairs of homologous series have the same C:H ratio in their general formulae? 1 aldehydes and ketones 2 carboxylic acids and esters 3 alkenes...
In which reaction does an element undergo the largest change in oxidation state?
Use of the Data Booklet is relevant to this question. The 68Ge isotope is medically useful because it undergoes a natural radioactive process to gi...
Sodium borohydride, NaBH4, and boron trifluoride, BF3, are compounds of boron. What are the shapes around boron in the borohydride ion and in boron...
Use of the Data Booklet is relevant to this question. A reaction which causes the presence of oxides of nitrogen in car exhausts is the formation o...
In the table below, • '+' means that this type of standard enthalpy change can only have positive values, • '-' means that this type of standard en...
Use of the Data Booklet is relevant to this question. The volume of a sample of ammonia is measured at a temperature of 60°C and a pressure of 103 ...
Aluminium is extracted by the electrolysis of a molten mixture containing aluminium oxide. By a similar method, magnesium is extracted by the elect...
Some car paints contain small flakes of silica, SiO2. In the structure of solid SiO2 • each silicon atom is bonded to x oxygen atoms, • each oxygen...
John Dalton's atomic theory, published in 1808, contained four predictions about atoms. Which of his predictions is still considered to be correct?
A student calculated the standard enthalpy change of formation of ethane, C2H6, using a method based on standard enthalpy changes of combustion. He...