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.
Monopotassium citrate is used as an emulsifying agent in powdered milk and in powdered soups. It may be represented by the formula shown. CH₂CO₂H H...
The diagram shows the Boltzmann distribution of energies in 1 mole of a gas. The gas can take part in a reaction with an activation energy, Ea. [Fi...
Four electronic configurations are shown below. Three of these configurations belong to atoms of the elements chlorine, sodium and vanadium. Which ...
Elements X and Y are in the same group of the Periodic Table. The table shows the first six ionisation energies of X and Y in kJ mol¯¹. 1st: X 800,...
In China, the concentration of blood glucose, C₆H₁₂O₆, is measured in mmol / l. In Pakistan, the concentration of blood glucose is measured in mg /...
Each of the four species in this question are isolated and gaseous. Which species is not planar?
Argon is a gas used to fill electric light bulbs. Under which conditions of pressure and temperature will argon behave most like an ideal gas? pres...
0.10 g of the volatile liquid X formed 0.025 dm³ of vapour at 100 °C and atmospheric pressure. 1 mol of vapour occupies 22.4 dm³ at 0 °C and atmosp...
The equation for the complete combustion of propan-1-ol is shown. CH₃CH₂CH₂OH(l) + 4½ O₂(g) → 3CO₂(g) + 4H₂O(l) Standard enthalpy changes of format...
In the treatment of domestic water supplies, chlorine is added to the water to form HClO. Cl₂(aq) + H₂O(l) → H⁺(aq) + Cl⁻(aq) + HClO(aq) The HClO r...
When solid ammonium chloride dissociates at a certain temperature in a 0.500 dm³ container, ammonia and hydrogen chloride are formed. NH₄Cl(s) ⇌ NH...
Which stage in the free radical substitution of ethane by chlorine has the lowest activation energy?
Sodium and sulfur react together to form sodium sulfide, Na₂S. How do the atomic radius and ionic radius of sodium compare with those of sulfur? at...
Solid aluminium chloride sublimes at 178 °C. Which structure best represents the species in the vapour at this temperature?
A 0.005 mol sample of anhydrous calcium carbonate was completely thermally decomposed to give 100 cm³ of gas measured at a certain temperature and ...
Ammonia gas, NH₃, and hydrogen sulfide gas, H₂S, react together to form the salt ammonium sulfide, (NH₄)₂S. Ammonium sulfide dissolves in water to ...
A solid, T, was placed in an excess of the liquid U. A colourless gas was given off and a white precipitate was seen. The precipitate was not T. Wh...
Nitrogen(II) oxide, NO, nitrogen(IV) oxide, NO₂, carbon monoxide, CO, and unburnt hydrocarbons are present in the exhaust gases of internal combust...
An excess of chlorine gas, Cl₂, is passed through 60 cm³ of cold aqueous 0.1 mol dm⁻³ sodium hydroxide. In a separate experiment an excess of chlor...
Fluorine and iodine are Group 17 elements. Their melting points are different due to differing strengths of van der Waals' forces between molecules...
Chlorofluorocarbons damage the ozone layer by undergoing reactions with a free radical mechanism. The first stage of this is initiation. Which equa...
Synthetic resins can be made by polymerisation of a variety of monomers including prop-2-en-1-ol, CH₂=CHCH₂OH. Which structure represents the repea...
Oct-1-ene, CH₃(CH₂)₅CH=CH₂, can be thermally cracked. Which combination of compounds W, X, Y and Z can be obtained by thermally cracking oct-1-ene?...
A cycloalkene with the molecular formula C₇H₁₂ was oxidised by hot concentrated acidified MnO₄. The only organic product was 2-methylhexane-1,6-dio...
1-chloro-1-methylcyclohexane is hydrolysed by heating with NaOH(aq). The reaction pathway is shown. [Diagram showing reaction path and energy profi...
Malic acid is found in apples. [Figure of malic acid structure] Which reagent will react with only one of the –OH groups in the malic acid molecule?
Which organic compound would not give either a yellow precipitate when treated with alkaline aqueous iodine or an orange precipitate when treated w...
In which reaction is the organic compound oxidised?
How many of the following compounds produce a carboxylic acid on heating under reflux with an excess of hot acidified K₂Cr₂O₇? CH₃CH₂CHO, CH₃COCH₃,...
How many isomeric esters, including structural isomers and stereoisomers, can be made with the molecular formula C₅H₁₀O₂, if methanoic acid is one ...
Compound X, C₄H₈O₂, has an unbranched carbon chain. An aqueous solution of X has an approximate pH of 3. Compound Y, C₃H₈O, is a secondary alcohol....
In an experiment, 10 cm³ of an organic compound, J, in the gaseous state was sparked with an excess of oxygen. 20 cm³ of carbon dioxide and 5 cm³ o...
Three elements, X, Y and Z, have electronic configurations as shown. X 2,6 Y 2,8,1 Z 2,8,7 Which formulae represent compounds that conduct electric...
In this question, all gases can be assumed to behave ideally. A chemist heats a mixture of nitrogen and oxygen gases in a sealed container at a con...
An ethanol burner can be used to heat water. If appropriate measurements are taken, a value for the enthalpy of combustion of ethanol can be calcul...
The first ionisation energies of twenty successive elements in the Periodic Table are represented in the graph. The letters given are not the norma...
The diagram shows a compound used as a flame retardant. [Figure of brominated compound structure] Which statements about this structure are correct...
One of the active ingredients in tea-tree oil is terpinen-4-ol. In the diagram of the skeletal formula of terpinen-4-ol, three of the carbon atoms ...
Which syntheses will be successful? 1 CH₃CH₂CH₃ from CH₃CH=CH₂ + LiAlH₄ 2 CH₃CH(OH)CH₃ from CH₃COCH₃ + NaBH₄ 3 CH₃CH₂CH₂OH from CH₃CH₂CHO + NaBH₄
Which would contain 9.03 × 10²³ oxygen atoms?
In some fireworks there is a reaction between powdered aluminium and powdered barium nitrate. Heat is evolved, an unreactive gas is produced, and a...
Which organic compound has the highest boiling point?
At a temperature of 2500K and a pressure of 1.00 × 10⁻⁴Pa a sample of 0.321 g of sulfur vapour has a volume of 2.08 × 10⁻³ m³. What is the molecula...
Which reaction involves a decrease in the bond angle at a carbon atom?
In the high temperatures of car engines, nitrogen reacts with oxygen to give nitrogen monoxide. ½N₂(g) + ½O₂(g) → NO(g) ΔH° = +90 kJ mol⁻¹ This rea...
A reaction sequence is shown. 1 2 3 4 SO₂ SO₃ H₂SO₄ H₂S SO₂ In each stage of this sequence the sulfur is oxidised, reduced or neither oxidised nor ...
Hydrogen and carbon dioxide gases are mixed at 800 K. A reversible reaction takes place. H₂(g) + CO₂(g) ⇌ H₂O(g) + CO(g) At equilibrium, the partia...
A reaction involved in the Contact process is shown. 2SO₂(g) + O₂(g) ⇌ 2SO₃(g) ΔH° = –197 kJ mol⁻¹ The reaction is investigated at 200 kPa and 700 ...
The Boltzmann distribution for the hydrogenation of an alkene at a particular temperature in the absence of a catalyst is shown. [Figure 11.1] Whic...
The elements magnesium and sulfur each form doubly charged ions. How do the atomic radii and ionic radii of these elements compare?