Balanced equations and associated calculations: AQA A‑Level Chemistry questions

AQA A-Level Chemistry past-paper questions on 3.1.2.5 Balanced equations and associated calculations, 2008–2025, with mark schemes and examiner’s reports where available.

All 292 questions on Balanced equations and associated calculations, as a list

June 2025, Paper 1, Q03.7 (1 mark): Calculate the mean titre from the student’s results. [1 mark] cm3
June 2025, Paper 1, Q03.8 (7 marks): Calculate the Mr of M2[Cu(C2O4)2(H2O)2] Identify M. [7 marks] Mr of M2[Cu(C2O4)2(H2O)2] Identity of M
June 2025, Paper 2, Q05.2 (4 marks): The yield of TNT in this reaction is 42.5%. Calculate the mass, in g, of TNT (Mr = 227.0) obtained from 1050 cm3 of methylbenzene. Methylbenzene has density = 0
June 2025, Paper 2, Q08.4 (4 marks): A mixture of methane and propane has a volume of 40 cm3 This mixture needs exactly 170 cm3 of oxygen for complete combustion. The equations for these reactions
June 2025, AS Paper 1, Q01.1 (2 marks): Calculate the percentage atom economy to form TiCl4 in this first stage of the extraction. [2 marks] Percentage atom economy
June 2025, AS Paper 1, Q01.2 (1 mark): Suggest one economic advantage of using a process with a high percentage atom economy. [1 mark]
June 2025, AS Paper 1, Q05.1 (5 marks): Calculate the relative molecular mass of H2A [5 marks] Relative molecular mass of H2A
June 2025, AS Paper 1, Q05.2 (1 mark): The uncertainty in the use of the burette in each titration is ±0.15 cm3 Calculate the percentage uncertainty in the use of the burette in titration 1. [1 mark]
June 2025, AS Paper 1, Q05.3 (8 marks): Suggest one way to reduce the percentage uncertainty in each titration without changing the apparatus. Justify your answer. [2 marks] Suggestion Justification 0
June 2025, AS Paper 1, Q13 (1 mark): What is the maximum mass of sodium chloride that can be made from 10.0 g of sodium and 10.0 g of chlorine? [1 mark] A 8.24 g B 16.5 g C 20.0 g D 25.4 g
June 2025, AS Paper 1, Q21 (1 mark): A student is asked to prepare a solution of hydrochloric acid with a concentration of 0.0400 mol dm–3 What volume of distilled water should the student add to 2
June 2024, Paper 1, Q02.4 (1 mark): The diagrams in Figure 2 show the part of a pipette with the graduation line. Which diagram identifies the pipette that is correctly filled? [1 mark] Tick () o
June 2024, Paper 1, Q02.5 (6 marks): Solubility can be quoted as ‘g of solute per 100 cm3 of solution’. Table 1 shows the results of the titrations between strontium hydroxide and hydrochloric acid
June 2024, Paper 1, Q06.4 (4 marks): 0.151 g of impure NH4VO3 is added to dilute sulfuric acid to form a solution containing aqueous VO2+ ions. All the VO3– ions are converted to VO2+ ions. These V
June 2024, Paper 2, Q03.4 (4 marks): A sample of butane has a volume of 20 cm3 at room temperature and pressure. The sample is burned completely in 1350 cm3 of air. The final mixture is cooled to r
June 2024, Paper 3, Q08 (1 mark): Compound P is converted into compound R by a two-stage synthesis via compound Q. The yields for the individual steps are: P → Q 50% Q → R 30% What is the overal
June 2024, AS Paper 1, Q07.1 (1 mark): Each reading from the balance has an uncertainty of ±0.005 g Calculate the percentage uncertainty in using the balance in this experiment. [1 mark] Percentage u
June 2024, AS Paper 1, Q07.2 (1 mark): Calculate the amount, in moles, of hydrochloric acid that was added to the tablets in Step 3. Give your answer to an appropriate precision. [1 mark] Amount of h
June 2024, AS Paper 1, Q07.3 (6 marks): Use your answer to Question 07.2 and the information given to calculate the percentage by mass of magnesium oxide in the tablets. [6 marks] Percentage by mass o
June 2024, AS Paper 1, Q10 (1 mark): What is the percentage atom economy for the formation of sodium nitrate in the reaction between sodium carbonate and nitric acid? Na2CO3 + 2 HNO3 → 2 NaNO3 + H2
June 2024, AS Paper 1, Q12 (1 mark): The table shows some results from a titration. Titration Rough Titre 1 Titre 2 Titre 3 Initial reading / cm3 0.00 11.30 0.00 8.55 Final reading / cm3 26.85 37.2
June 2024, AS Paper 1, Q17 (1 mark): Ammonia is oxidised as shown. w NH3 + x O2 → y H2O + z NO Which whole number values for w, x, y and z balance the equation? [1 mark] w x y z A 2 3 3 2 B 4 7 4 4
June 2024, AS Paper 1, Q23 (1 mark): Which of these practical steps will improve the accuracy of a titration? [1 mark] A Using a 10.0 cm3 pipette instead of a 25.0 cm3 pipette. B Rinsing the sides
June 2024, AS Paper 2, Q05.1 (7 marks): Magnesium reacts with hydrochloric acid. Mg(s) + 2 HCl(aq) → MgCl2(aq) + H2(g) 0.400 g of magnesium is added to 20.0 cm3 of 1.50 mol dm–3 hydrochloric acid. Ide
June 2024, AS Paper 2, Q05.2 (2 marks): Propane (C3H8) undergoes complete combustion in a plentiful supply of oxygen. Give an equation for the complete combustion of propane. Use this equation to calc
June 2024, AS Paper 2, Q08 (1 mark): The equation shows how P reacts with Q to make R and S. P + 2 Q → R + S When a mixture of 0.25 mol of P and 0.40 mol of Q react, 0.15 mol of R is obtained. What
June 2024, AS Paper 2, Q21 (1 mark): This is the equation for the conversion of 1,2-dibromoethane to butanedinitrile. CH2BrCH2Br + 2 KCN → NCCH2CH2CN + 2 KBr What is the percentage atom economy for
June 2023, Paper 1, Q06.1 (1 mark): Calculate the mass, in g, of solid barium hydroxide (Mr = 171.3) needed to prepare 250 cm3 of 0.100 mol dm–3 barium hydroxide solution. [1 mark] Mass g
June 2023, Paper 1, Q06.2 (3 marks): The mass of barium hydroxide from Question 06.1 is dissolved in a beaker containing 150 cm3 of distilled water. Describe how this solution is used to make 250 c
June 2023, Paper 1, Q06.3 (1 mark): Before the first titration, the 25 cm3 pipette is rinsed with a small volume of the 0.100 mol dm–3 barium hydroxide solution. State why it is good practice to r
June 2023, Paper 1, Q06.4 (1 mark): Hydrochloric acid is added to the burette using a funnel. State why it is good practice to remove the funnel from the burette before the titration. [1 mark]
June 2023, Paper 1, Q06.5 (3 marks): In a different experiment, 0.952 g of solid barium hydroxide is used to make 250 cm3 of standard barium hydroxide solution. 25.0 cm3 of this barium hydroxide so
June 2023, Paper 1, Q06.6 (1 mark): The uncertainty in the 25.0 cm3 of solution from the pipette is ±0.05 cm3 The total uncertainty in the 24.50 cm3 of solution from the burette is ±0.15 cm3 Calcu
June 2023, Paper 1, Q07.8 (7 marks): Hydrated aluminium sulfate, Al2(SO4)3.xH2O, is soluble in water. The relative formula mass and value of x can be found from a titration experiment. Aqueous [Al(
June 2023, Paper 2, Q07.4 (2 marks): A 600 cm3 sample of propanone is mixed with 2800 cm3 of oxygen in a container at 60 °C and 100 kPa. The mixture is ignited. When the reaction is complete, the r
June 2023, Paper 3, Q01.7 (5 marks): A student uses the method to prepare some ethyl ethanoate. The student adds 10.0 cm3 of ethanol (Mr = 46.0) to 5.25 g of ethanoic acid (Mr = 60.0) and obtains 5
June 2023, Paper 3, Q06.1 (2 marks): Show, by calculation, that the calcium hydroxide is in excess. [2 marks]
June 2023, AS Paper 1, Q02.6 (6 marks): Mg(OH)2 is used as an antacid to treat indigestion. A student does an experiment to determine the percentage by mass of Mg(OH)2 in an indigestion tablet. 40.0 c
June 2023, AS Paper 1, Q03.1 (3 marks): Suggest three improvements to this method. [3 marks] 1 2 3
June 2023, AS Paper 1, Q03.2 (1 mark): A different student uses the correct method to prepare 250 cm3 of sodium carbonate solution in a volumetric flask. The uncertainty for the volumetric flask is ±
June 2023, AS Paper 1, Q10 (1 mark): Which suggestion improves the accuracy of the titres? [1 mark] A Rinsing the conical flask with vinegar between each titration. B Rinsing the conical flask with
June 2023, AS Paper 1, Q11 (1 mark): Which suggestion decreases the percentage uncertainty in the mean titre? [1 mark] A Use a more dilute solution of sodium hydroxide in the burette. B Use a more
June 2023, AS Paper 1, Q12 (1 mark): Which reaction has the highest percentage atom economy for the production of hydrogen? [1 mark] A LiH + H2O → LiOH + H2 B CO + H2O → CO2 + H2 C 2 Al + 3 H2O → A
June 2023, AS Paper 2, Q07.3 (5 marks): In a similar experiment, 12.0 cm3 of 2,3,3-trimethylbutan-1-ol (Mr = 116.0) produces 6.12 g of 2,3,3-trimethylbut-1-ene. Calculate the percentage yield. density
June 2023, AS Paper 2, Q17 (1 mark): What is the minimum volume, in dm3, of air needed for the complete combustion of 1 dm3 of methane? Assume that air contains 20% of oxygen by volume. Assume that
June 2023, AS Paper 2, Q23 (1 mark): What is the atom economy for the formation of ethylamine in this reaction? CH3CH2Br + 2 NH3 → CH3CH2NH2 + NH4Br [1 mark] A 31.5% B 35.7% C 36.1% D 41.3%
June 2022, Paper 1, Q03.1 (5 marks): Give an ionic equation for the reaction between potassium manganate(VII) and acidified hydrogen peroxide. Calculate the concentration, in mol dm–3, of hydrogen
June 2022, Paper 1, Q03.4 (5 marks): Hydrogen peroxide decomposes to form water and oxygen. Give an equation for this reaction. Calculate the amount, in moles, of hydrogen peroxide that would be ne
June 2022, Paper 2, Q05.6 (4 marks): Calculate the mass, in g, of hexan-2-ol formed from 11.0 cm3 of hex-1-ene if the yield is 31.0% Give your answer to 1 decimal place. Density of hex-1-ene = 0.67
June 2022, Paper 2, Q09.1 (2 marks): A suitable target titre for the titration is 30.0 cm3 of 0.025 mol dm−3 Br2(aq). Justify why a much smaller target titre would not be appropriate. Calculate the
June 2022, Paper 2, Q09.2 (5 marks): Calculate a suitable mass of olive oil to transfer to the volumetric flask using your answer to Question 09.1 and the structure of Y. Assume that the olive oil
June 2022, Paper 2, Q09.3 (2 marks): Suggest an extra step to ensure that the mass of olive oil in the solution is recorded accurately. Justify your suggestion. [2 marks] Extra step Justification
June 2022, Paper 2, Q09.4 (1 mark): State the reason for inverting the flask several times. [1 mark]
June 2022, Paper 3, Q07 (1 mark): Complete combustion of 0.0100 mol of an organic acid produced 0.0200 mol of carbon dioxide. The same amount of the acid required 20 cm3 of 1.00 mol dm–3 NaOH (a
June 2022, AS Paper 1, Q02.1 (2 marks): A student makes a solution of citric acid by dissolving some solid citric acid in water. Describe a method to add an accurately known mass of solid to a beaker
June 2022, AS Paper 1, Q02.2 (3 marks): The student dissolves 0.834 g of citric acid in water and makes the solution up to 500 cm3 Calculate the concentration, in mol dm–3, of citric acid in this solu
June 2022, AS Paper 1, Q02.3 (6 marks): The student uses this method to complete a titration. • Rinse a burette with distilled water. • Fill the burette with sodium hydroxide solution. • Use a measuri
June 2022, AS Paper 1, Q02.4 (2 marks): Table 1 shows the student’s burette readings after the mistakes in the practical procedure have been corrected. Table 1 Rough Run 1 Run 2 Run 3 Final reading /
June 2022, AS Paper 1, Q02.5 (1 mark): The total uncertainty in the use of the burette is ±0.15 cm3 Calculate the percentage uncertainty in the use of the burette in Run 1. [1 mark] Percentage uncert
June 2022, AS Paper 2, Q04.1 (5 marks): TNT (C7H5N3O6) is an explosive because it can decompose very quickly and exothermically to form a large volume of gas. An equation for this decomposition is 2 C
June 2022, AS Paper 2, Q04.2 (1 mark): Alkenes have the general formula CnH2n When alkenes undergo complete combustion, 1.0 mol of CnH2n reacts with 3n 2 mol of oxygen. Calculate the volume of oxygen
June 2022, AS Paper 2, Q04.3 (1 mark): Alkanes have the general formula CnH2n+2 Alkanes undergo complete combustion in a plentiful supply of oxygen. CnH2n+2 + x O2 → n CO2 + (n+1) H2O Determine x in
June 2022, AS Paper 2, Q05.3 (2 marks): In an experiment, 10.3 g of 1-iodopropane (Mr = 169.9) are reacted with an excess of ammonia. 2.3 g of propylamine (Mr = 59.0) are produced. Calculate the perce
June 2022, AS Paper 2, Q06.1 (2 marks): The equation for a process used to manufacture CCl3F is SbF3Br2 + CCl4 → CCl3F + SbF2Br2Cl Calculate the percentage atom economy for the production of CCl3F in
November 2021, Paper 1, Q04.4 (6 marks): Iron reacts with dilute hydrochloric acid to form iron(II) chloride and hydrogen. Fe(s) + 2 HCl(aq) → FeCl2(aq) + H2(g) A 0.998 g sample of pure iron is added t
November 2021, Paper 2, Q01.3 (6 marks): A 1.450 g sample of coconut oil is heated with 0.421 g of KOH in aqueous ethanol until all of the triester is hydrolysed. The mixture is cooled. The remaining K
November 2021, Paper 2, Q08.4 (2 marks): Suggest why chemists usually aim to design production methods • with fewer steps • with a high percentage atom economy. [2 marks] Fewer steps High percentage at
November 2021, Paper 3, Q01.3 (4 marks): Sodium ethanedioate is used to find the concentration of solutions of potassium manganate(VII) by titration. The equation for this reaction is 2 MnO4– + 16 H+ +
November 2021, Paper 3, Q01.4 (1 mark): Figure 1 shows the 25.0 cm3 pipette used to measure the sodium ethanedioate solution. Figure 1 On Figure 1, draw the meniscus of the solution when the pipette i
November 2021, Paper 3, Q01.5 (2 marks): Potassium manganate(VII) is oxidising and harmful. Sodium ethanedioate is toxic. Suggest safety precautions, other than eye protection, that should be taken whe
November 2021, Paper 3, Q01.7 (2 marks): Figure 2 shows the burette containing potassium manganate(VII) solution. Figure 2 Give two practical steps needed before recording the initial burette reading.
November 2021, Paper 3, Q06.5 (4 marks): After correcting the mistakes, the student heats a reaction mixture containing 6.50 g of propan-1-ol with an excess of the oxidising agent. The propanoic acid s
November 2021, Paper 3, Q25 (1 mark): Which compound needs the greatest amount of oxygen for the complete combustion of 1 mol of the compound? [1 mark] A ethanal B ethanol C ethane-1,2-diol D methan
November 2021, Paper 3, Q29 (1 mark): Nitration of 1.70 g of methyl benzoate (Mr = 136.0) produces methyl 3-nitrobenzoate (Mr = 181.0). The percentage yield is 65.0% What mass, in g, of methyl 3-nit
November 2021, AS Paper 1, Q06 (5 marks): Calcium sulfide reacts with calcium sulfate as shown. CaS + 3 CaSO4 → 4 CaO + 4 SO2 2.50 g of calcium sulfide are heated with 9.85 g of calcium sulfate until th
November 2021, AS Paper 1, Q08.1 (6 marks): Use the results in Table 3 to calculate the mean titre value. Use the mean titre to calculate the percentage by mass of sodium ethanoate in the original sample.
November 2021, AS Paper 1, Q08.2 (2 marks): The student rinses the burette with deionised water before filling with sodium hydroxide solution. State and explain the effect, if any, that this rinsing will
November 2021, AS Paper 2, Q03.2 (4 marks): The student reacts 2.0 cm3 of propan-2-ol (CH3CH(OH)CH3) with an excess of acidified potassium dichromate(VI). The student obtains 0.954 g of propanone (CH3COCH
November 2021, AS Paper 2, Q06.2 (2 marks): In the second experiment, another flask is used for a combustion reaction. Method • Remove all the air from the flask. • Add 0.0010 mol of 2,2,4-trimethylpentan
November 2021, AS Paper 2, Q23 (1 mark): What is the percentage atom economy for the production of ethanol from glucose? C6H12O6 → 2 C2H5OH + 2 CO2 [1 mark] A 25.6% B 27.1% C 51.1% D 54.2%
November 2020, Paper 1, Q08.1 (7 marks): Use all the information given to calculate the percentage by mass of NaClO in the original bleach solution. Give your answer to 3 significant figures. [7 marks]
November 2020, Paper 1, Q08.2 (1 mark): The total uncertainty from two readings and an end point error in using a burette is ± 0.15 cm3 What is the total percentage uncertainty in using the burette in
November 2020, Paper 2, Q04.5 (5 marks): A 6.01 g sample of salicylic acid (Mr = 138.0) is reacted with 10.5 cm3 of ethanoic anhydride (Mr = 102.0). In the reaction the yield of aspirin is 84.1% The de
November 2020, Paper 3, Q03.4 (2 marks): The concentration of iron(III) in the solution is 4.66 x 10–3 mol dm–3 Calculate the mass, in mg, of iron in the tablet used to make the 250 cm3 of solution. [2
November 2020, Paper 3, Q36 (1 mark): A student rinsed the apparatus before starting an acid-base titration. The results of the titration showed that the volume of acid added from the burette was la
November 2020, AS Paper 1, Q02.1 (5 marks): Calculate the mass of sodium hydroxide used to make the original solution. [5 marks] Mass of sodium hydroxide g
November 2020, AS Paper 1, Q02.2 (1 mark): The student uses a funnel to fill the burette with sulfuric acid before starting the titration. After filling, the student forgets to remove the funnel from the
November 2020, AS Paper 1, Q02.3 (1 mark): State one advantage of using a conical flask rather than a beaker for the titration. [1 mark]
November 2020, AS Paper 1, Q07.5 (1 mark): Calculate, using your answer to Question 07.4, the mass, in grams, of sodium iodide in the mixture. Mr (NaI) = 149.9 [1 mark] Mass of sodium iodide g
November 2020, AS Paper 1, Q07.6 (2 marks): Calculate, using your answer to Question 07.5, the percentage by mass of sodium chloride in the mixture. [2 marks] Percentage of sodium chloride
November 2020, AS Paper 2, Q03 (6 marks): A student investigates two experimental methods of making methylpropanal. The equations for these two methods are shown. In each method, the student uses 1.00 g
November 2020, AS Paper 2, Q07.3 (5 marks): Ethanedioic acid reacts with an excess of sodium hydroxide to form sodium ethanedioate. H2C2O4 (aq) + 2 NaOH (aq) → Na2C2O4 (aq) + 2 H2O (I) A student mixes 10.
November 2020, AS Paper 2, Q19 (1 mark): What is the minimum volume of 0.0500 mol dm–3 aqueous bromine needed to react completely with 0.0200 g of buta-1,3-diene? (Mr of buta-1,3-diene = 54.0) [1 mark]
June 2019, Paper 1, Q06.1 (6 marks): Calculate the percentage of copper by mass in the alloy. Give your answer to the appropriate number of significant figures. [6 marks] % copper
June 2019, Paper 1, Q06.2 (2 marks): Suggest two ways that the student could reduce the percentage uncertainty in the measurement of the volume of sodium thiosulfate solution, using the same appara
June 2019, Paper 1, Q07.1 (2 marks): A sample of sulfur trioxide was heated and allowed to reach equilibrium at a given temperature. The equilibrium mixture contained 6.08 g of sulfur dioxide. Calc
June 2019, Paper 2, Q02.4 (5 marks): In this preparation, the student added an excess of concentrated phosphoric acid to 14.4 g of cyclohexanol (Mr = 100.0). The student obtained 4.15 cm3 of cycloh
June 2019, Paper 2, Q08.7 (3 marks): Calculate the mass, in kg, of hydroquinone (Mr = 110.0) needed to produce 250 kg of paracetamol. [3 marks] Mass kg
June 2019, Paper 2, Q10.2 (4 marks): A student dissolved some of the dicarboxylic acid from Question 10.1 in water and made up the solution to 250 cm3 in a volumetric flask. In a titration, a 25.0
June 2019, Paper 3, Q01.1 (1 mark): Give the simplest ionic equation for this reaction. [1 mark]
June 2019, Paper 3, Q05.2 (1 mark): The titration results are shown in Table 3. Table 3 1 2 3 Final volume / cm3 22.90 45.60 22.60 Initial volume / cm3 0.00 22.90 0.00 Titre / cm3 22.90 22.70 22.6
June 2019, Paper 3, Q05.5 (1 mark): Name the piece of apparatus used for these stages of the method. [1 mark] Taking the 25.0 cm3 portions Adding the potassium manganate(VII) solution
June 2019, Paper 3, Q05.6 (1 mark): The balance used to weigh the 680 mg of iron wire has an uncertainty of ±0.005 g A container was weighed and its mass was subtracted from the total mass of the
June 2019, Paper 3, Q06 (1 mark): Which amount of sodium hydroxide would react exactly with 7.5 g of a diprotic acid, H2A (Mr = 150)? [1 mark] A 50 cm3 of 0.05 mol dm–3 NaOH(aq) B 100 cm3 of 0.5
June 2019, Paper 3, Q07 (1 mark): Lead(II) nitrate and potassium iodide react according to the equation Pb(NO3)2(aq) + 2 KI(aq) → PbI2(s) + 2 KNO3(aq) In an experiment, 25.0 cm3 of a 0.100 mol d
June 2019, AS Paper 1, Q06.1 (5 marks): Use the results to calculate the Mr of H2A [5 marks] Mr of H2A
June 2019, AS Paper 1, Q06.2 (1 mark): The uncertainty in using the pipette in this experiment is ±0.06 cm3 Calculate the percentage uncertainty in using the pipette. [1 mark] % uncertainty
June 2019, AS Paper 1, Q06.3 (1 mark): Before adding the solution from the burette in the rough titration, there was an air bubble below the tap. At the end of this titration the air bubble was not t
June 2019, AS Paper 1, Q06.4 (1 mark): During the titration the student washed the inside of the conical flask with some distilled water. Suggest why this washing does not give an incorrect result. [
June 2019, AS Paper 1, Q07.2 (4 marks): A mixture of magnesium oxide and magnesium hydroxide has a mass of 3200 mg This mixture is reacted with carbon dioxide to form magnesium carbonate and water. Th
June 2019, AS Paper 1, Q21 (1 mark): The equation below represents the complete combustion of butane. C4H10(g) + 6 1 2 O2(g)  4 CO2(g) + 5 H2O(g) 20 cm3 of butane are completely burned in 0.20 dm3
June 2019, AS Paper 1, Q23 (1 mark): What is the percentage yield when 20 g of aluminium are produced from 50 g of aluminium oxide? 2Al2O3 → 4Al + 3O2 [1 mark] A 76% B 40% C 33% D 19%
June 2019, AS Paper 2, Q02.3 (2 marks): Calculate the percentage atom economy for the formation of D in this reaction. Give your answer to the appropriate number of significant figures. [2 marks] % at
June 2019, AS Paper 2, Q04.3 (2 marks): Sulfur dioxide is produced in the combustion of fossil fuels. The total emissions of sulfur dioxide in the UK have fallen dramatically since 1970. Sulfur dioxid
June 2019, AS Paper 2, Q07.2 (6 marks): Describe how to prepare 250 cm3 of an aqueous standard solution of propanedioic acid containing an accurately measured mass of the acid. Include essential pract
June 2019, AS Paper 2, Q07.3 (2 marks): Calculate the mass, in mg, of propanedioic acid (Mr = 104.0) needed to prepare 250 cm3 of a 0.00500 mol dm–3 solution. [2 marks] Mass of propanedioic acid mg
June 2019, AS Paper 2, Q08.1 (3 marks): Calculate the minimum volume, in cm3, of 0.40 mol dm–3 potassium dichromate(VI) solution needed to oxidise 6.0 cm3 of propan-1-ol to propanal. Mr of propan-1-ol
June 2018, Paper 1, Q04.5 (3 marks): A student added 6 cm3 of 0.25 mol dm–3 barium chloride solution to 8 cm3 of 0.15 mol dm–3 sodium sulfate solution. The student filtered off the precipitate and
June 2018, Paper 1, Q08.2 (6 marks): When 250 mg of sodium were added to 500 cm3 of water at 25 °C a gas was produced. Give an equation for the reaction that occurs. Calculate the volume, in cm3, o
June 2018, Paper 1, Q10.1 (7 marks): A student added 627 mg of hydrated sodium carbonate (Na2CO3.xH2O) to 200 cm3 of 0.250 mol dm–3 hydrochloric acid in a beaker and stirred the mixture. After the
June 2018, Paper 3, Q03.1 (3 marks): The student collected 5.97 g of cyclohexene in the experiment. Calculate the percentage yield of cyclohexene. [3 marks] Percentage yield %
June 2018, AS Paper 1, Q07.4 (4 marks): The concentration of ClO– ions in bleach solution can be found by reaction with iodide ions. The overall equation for this reaction is shown. ClO– + 2I– + 2H+ →
June 2018, AS Paper 1, Q13 (1 mark): A 30 cm3 sample of nitrogen was reacted with a 60 cm3 sample of fluorine according to the equation N2(g) + F2(g) → NF3(g) What is the volume of the gas mixture
June 2018, AS Paper 1, Q20 (1 mark): Which suggestion would improve the chances of obtaining concordant titres? [1 mark] A Invert the volumetric flask several times after adding the distilled water
June 2018, AS Paper 1, Q21 (1 mark): Which suggestion about rinsing the conical flask between each titration would improve the accuracy of the titrations? [1 mark] A Rinsing with acid. B Rinsing wi
June 2018, AS Paper 1, Q22 (1 mark): Which suggestion would reduce the overall measurement uncertainty in the titration? [1 mark] A Use less concentrated alkali in the burette. B Use phenolphthalei
June 2018, AS Paper 1, Q23 (1 mark): Which of these is important in ensuring that the student’s experiment is safe? [1 mark] A Do the titration in a fume cupboard. B Wear gloves when measuring out
June 2018, AS Paper 1, Q24 (1 mark): Which colour change is observed at the end point in each titration? [1 mark] A Yellow to red B Red to orange C Yellow to orange D Red to yellow
June 2018, AS Paper 2, Q02.1 (1 mark): The student rinsed the burette before filling it with the sodium hydroxide solution. State why the student should use sodium hydroxide solution rather than wate
June 2018, AS Paper 2, Q02.2 (1 mark): The student carried out several titrations. The results are shown in Table 2. Complete Table 2 to show the titre in each titration. [1 mark] Table 2 Titration R
June 2018, AS Paper 2, Q02.3 (2 marks): Calculate the mean titre using the concordant results. Give your answer to the appropriate number of significant figures. [2 marks] Mean titre cm3
June 2018, AS Paper 2, Q02.4 (1 mark): The total uncertainty when using the burette is ±0.15 cm3. This is the combination of uncertainties in the start reading, final reading and the determination of
June 2018, AS Paper 2, Q02.5 (3 marks): Use your answer to Question 02.3 to find the mass, in mg, of citric acid dissolved in 250 cm3 of the solution. The relative molecular mass (Mr) of citric acid i
June 2018, AS Paper 2, Q02.6 (1 mark): Calculate the percentage purity of this sample of citric acid. [1 mark] Percentage purity %
June 2018, AS Paper 2, Q17 (1 mark): Ethanol can be made from glucose by fermentation. C6H12O6 → 2C2H5OH + 2CO2 In an experiment, 268 g of ethanol (Mr = 46.0) were made from 1.44 kg of glucose (Mr
June 2017, Paper 1, Q11.1 (8 marks): A white solid is a mixture of sodium ethanedioate (Na2C2O4), ethanedioic acid dihydrate (H2C2O4.2H2O) and an inert solid. A volumetric flask contained 1.90 g of
June 2017, Paper 2, Q01.3 (3 marks): Calculate the mass, in grams, of CH3CH2CH2NH2 produced from 25.2 g of CH3CH2CH2Br in Reaction 2 assuming a 75.0% yield. Give your answer to the appropriate numb
June 2017, Paper 2, Q10.2 (5 marks): A sample of P was mixed with an excess of oxygen and the mixture ignited. After cooling to the original temperature, the total volume of gas remaining was 335 c
June 2017, Paper 3, Q03.2 (2 marks): Show, by calculation, that an excess of sodium hydroxide is used in this reaction. [2 marks] 10
June 2017, Paper 3, Q03.9 (3 marks): In a similar experiment, another student used 0.040 mol of ethyl benzoate and obtained 5.12 g of benzoic acid. Calculate the percentage yield of benzoic acid. S
June 2017, Paper 3, Q04.3 (2 marks): Calculate the concentration of HX in the original solution. [2 marks] Concentration mol dm−3
June 2017, Paper 3, Q11 (1 mark): What is the mass, in mg, of carbon formed when 3.0 × 10−3 mol of propene undergoes incomplete combustion? 2C3H6 + 3O2 → 6C + 6H2O [1 mark] A 9.0 × 10−3 B 3.6 ×
June 2017, Paper 3, Q19 (1 mark): The equation for the reaction between zinc and hydrochloric acid is Zn + 2HCl → ZnCl2 + H2 What is the minimum mass, in mg, of zinc (Ar = 65.4) needed to react
June 2017, Paper 3, Q33 (1 mark): Phenylethanone can be prepared by the reaction between ethanoyl chloride and benzene. In a preparation, with an excess of benzene, the mass of ethanoyl chloride
June 2017, AS Paper 1, Q06.1 (2 marks): Balance the equations for the two stages in this process. [2 mark ..…CuFeS2 + ..…O2 + ..…SiO2 → ..…Cu2S + ..…Cu2O + ..…SO2 + ..…FeSiO3 ……Cu2S + ……Cu2O → ……Cu +
June 2017, AS Paper 1, Q06.3 (4 marks): A passenger jet contains 4050 kg of copper wiring. A rock sample contains 1.25% CuFeS2 by mass. Calculate the mass, in tonnes, of rock needed to produce enough
June 2017, AS Paper 1, Q06.4 (2 marks): Copper can also be produced by the reaction of carbon with copper(II) oxide according to the equation 2CuO + C → 2Cu + CO2 Calculate the percentage atom economy
June 2017, AS Paper 1, Q08.6 (4 marks): In aqueous solution, nitrite ions react with acidified chlorate(V) ions according to the equation 2ClO3 − + 5NO2 − + 2H+ → Cl2 + 5NO3 − + H2O A 25.0 cm3 sample
June 2017, AS Paper 1, Q16 (1 mark): 1 6 25.0 cm3 samples of NaOH solution were taken by pipette from a beaker. These were then titrated with an aqueous solution of ethanoic acid. The concentration
June 2017, AS Paper 1, Q17 (1 mark): 1 7 A 20.0 cm3 sample of a 0.400 mol dm−3 aqueous solution of a metal bromide (MBrn) reacts exactly with 160 cm3 of 0.100 mol dm−3 aqueous silver nitrate. What
June 2017, AS Paper 2, Q05.1 (4 marks): The student found that 25.0 cm3 of the ethanedioic acid solution reacted completely with 25.30 cm3 of 0.500 mol dm−3 sodium hydroxide solution. Calculate the ma
June 2017, AS Paper 2, Q05.2 (1 mark): The student used a wash bottle containing deionised water when approaching the end-point to rinse the inside of the conical flask. Explain why this improved the
June 2017, AS Paper 2, Q05.3 (1 mark): Give the meaning of the term concordant titres. [1 mark]
June 2017, AS Paper 2, Q06.2 (3 marks): When 2.0 cm3 of 1-bromo-2-methylpropane (Mr = 136.9) were reacted with an excess of sodium hydroxide, 895 mg of 2-methylpropan-1-ol (Mr = 74.0) were obtained. T
June 2017, AS Paper 2, Q10 (1 mark): What is the burette reading for this transparent liquid? [1 mark] A 24.10 cm3 B 24.30 cm3 C 25.70 cm3 D 25.90 cm3
June 2017, AS Paper 2, Q11 (1 mark): A volumetric flask was used to prepare 250 cm3 of a solution. The solute was added from a plastic weighing container. Mass / g Weighing container with solute 10
June 2016, AS Paper 1, Q03.1 (3 marks): Calculate the mean titre and use this to determine the amount, in moles, of HCl that reacted with 25.0 cm3 of the MHCO3 solution. [3 marks
June 2016, AS Paper 1, Q03.2 (3 marks): Calculate the amount, in moles, of MHCO3 in 250 cm3 of the solution. Then calculate the experimental value for the Mr of MHCO3. Give your answer to the appropri
June 2016, AS Paper 1, Q03.3 (2 marks): The student identified use of the burette as the largest source of uncertainty in the experiment. Using the same apparatus, suggest how the procedure could be i
June 2016, AS Paper 1, Q03.4 (6 marks): Another student is required to make up 250 cm3 of an aqueous solution that contains a known mass of MHCO3. The student is provided with a sample bottle containi
June 2016, AS Paper 1, Q09.1 (4 marks): A student was given a powder made from a mixture of anhydrous barium chloride and anhydrous magnesium chloride. The student dissolved 1.056 g of the powder in w
June 2016, AS Paper 1, Q22 (1 mark): 2 2 30 cm3 of xenon are mixed with 20 cm3 of fluorine. The gases react according to the following equation. Assume that the temperature and pressure remain cons
June 2016, AS Paper 1, Q23 (1 mark): 2 3 Which of the following solutions would react exactly with a solution containing 0.0500 mol sulfuric acid? [1 mark] A 50.0 cm3 of 1.00 mol dm−3 KOH B 100.0 c
June 2016, AS Paper 1, Q24 (1 mark): In a car airbag, sodium azide (NaN3) decomposes to form sodium metal and nitrogen gas. 2NaN3(s) → 2Na(s) + 3N2(g) The sodium metal then reacts with potassium ni
June 2016, AS Paper 2, Q08.1 (3 marks): The equation for the reaction between ethanoic acid and magnesium is shown. 2CH3COOH(aq) + Mg(s) → (CH3COO)2Mg(aq) + H2(g) With the aid of calculations, show th
June 2016, AS Paper 2, Q11 (1 mark): Propene can be made by the dehydration of propan-2-ol. What is the percentage yield when 30 g of propene (Mr = 42.0) are formed from 50 g of propan-2-ol (Mr = 6
Specimen, Paper 2, Q09.4 (3 marks): In an experiment starting with 5.05 g of phenylamine, 4.82 g of purified product were obtained in step 1. Calculate the percentage yield in this reaction. Give
Specimen, Paper 3, Q02.2 (1 mark): Complete Table 2. [1 mark 0 2 . 2
Specimen, Paper 3, Q02.3 (2 marks): Mean titre = c Calculation Justification
Specimen, Paper 3, Q02.5 (1 mark): Percentage uncertainty = %
Specimen, Paper 3, Q02.6 (2 marks): 8
Specimen, Paper 3, Q04.3 (4 marks): Original concentration = Equation Calculation mol dm 3
Specimen, Paper 3, Q08 (1 mark): An ester is hydrolysed as shown by the following equation. RCOOR/ + H2O RCOOH + R/OH What is the percentage yield of RCOOH when 0.50 g of RCOOH (Mr = 100) is ob
Specimen, Paper 3, Q15 (1 mark): 8
June 2016, CHEM5 (old spec), Q9(d) (7 marks): Write an equation for the reaction between C2O42– ions and MnO4– ions in acidic solution. Calculate the percentage purity of the original sample of K3[Fe(C2O4)3
June 2016, CHEM1 (old spec), Q2(d)(ii) (2 marks): SCl2 reacts with NaF to form SF4 and S2Cl2 and one other product. Write an equation for the reaction. [2 marks] 2 2
June 2016, CHEM1 (old spec), Q3(a)(i) (2 marks): Write an equation for the reaction. [2 marks]
June 2016, CHEM1 (old spec), Q3(a)(ii) (1 mark): Suggest one observation that could be made during the reaction. [1 mark]
June 2016, CHEM1 (old spec), Q6(a) (4 marks): In the first step of the first method, phosphorus is burned in air at 500 ºC to produce gaseous phosphorus(V) oxide. P4(s) + 5O2(g) P4O10(g) 220 g of phosphorus
June 2016, CHEM1 (old spec), Q6(b) (3 marks): In the second step of the first method, phosphorus(V) oxide reacts with water to form phosphoric(V) acid. P4O10(s) + 6H2O(l) 4H3PO4(aq) Calculate the mass of ph
June 2016, CHEM1 (old spec), Q6(c) (4 marks): In the second method to produce phosphoric(V) acid, 3.50 kg of Ca3(PO4)2 are added to an excess of aqueous sulfuric acid. Ca3(PO4)2(s) + 3H2SO4(aq) 2H3PO4(aq) +
June 2016, CHEM1 (old spec), Q6(d) (1 mark): Explain whether the first method or the second method of production of phosphoric acid has the higher atom economy. You are not required to do a calculation. [1
June 2016, CHEM2 (old spec), Q7(a)(i) (1 mark): Write an equation for the reaction that takes place when ZnS is roasted in air. [1 mark]
June 2015, CHEM5 (old spec), Q8(b)(ii) (5 marks): Write an equation for the reaction between iron(II) ions and manganate(VII) ions. Use this equation and the information given to calculate the concentration of
June 2015, CHEM1 (old spec), Q1(d)(iii) (1 mark): Write an equation to show the formation of one mole of ClF3 from its elements. [1 mark]
June 2015, CHEM1 (old spec), Q3(c) (1 mark): Silicon dioxide reacts with hydrofluoric acid (HF) to produce hexafluorosilicic acid (H2SiF6) and one other substance. Write an equation for this reaction. [1 m
June 2015, CHEM1 (old spec), Q7(a) (5 marks): Sodium azide is made by reacting dinitrogen monoxide gas with sodium amide (NaNH2) as shown by the equation. 2NaNH2 + N2O NaN3 + NaOH + NH3 Calculate the mass o
June 2015, CHEM1 (old spec), Q7(c)(i) (3 marks): A 500 cm3 volume of the nitrous acid solution was used to destroy completely 150 g of the sodium azide. Calculate the concentration, in mol dm–3, of the nitrous
June 2015, CHEM1 (old spec), Q7(c)(ii) (1 mark): Nitrous acid decomposes on heating. Balance the following equation for this reaction. [1 mark] HNO2 HNO3 + NO + H2O
June 2015, CHEM2 (old spec), Q7(a)(i) (1 mark): Balance the following equation for this reaction of glucose to form propanone, carbon dioxide and water. [1 mark] C6H12O6 CH3COCH3 + CO2 + H2O
June 2015, CHEM2 (old spec), Q9(c) (4 marks): Pure vanadium, for nuclear reactors, is formed by the reaction of hydrogen with purified VCl2 Write an equation for this reaction in which the only other produc
June 2014, CHEM4 (old spec), Q5(e)(i) (1 mark): Acrylonitrile can be formed from propene. Write an equation for the reaction of propene with ammonia and oxygen to form acrylonitrile and one other product. [1
June 2014, CHEM5 (old spec), Q8(a) (5 marks): Use this information to calculate a value for the mass of FeSO4.7H2O in the sample of X. [5 marks]
June 2014, CHEM1 (old spec), Q2(a)(ii) (1 mark): Calculate the amount, in moles, of oxygen gas produced in this reaction. [1 mark]
June 2014, CHEM1 (old spec), Q2(b) (1 mark): Suggest a name for this type of reaction that iron(III) nitrate undergoes. [1 mark]
June 2014, CHEM1 (old spec), Q2(c) (1 mark): Suggest why the iron(III) oxide obtained is pure. Assume a complete reaction. [1 mark]
June 2014, CHEM1 (old spec), Q3(b)(ii) (2 marks): Balance the following equation to show how anhydrous nickel(II) chloride can be obtained from the hydrated salt using SOCl2 Identify one substance that could re
June 2014, CHEM1 (old spec), Q6(a)(i) (5 marks): A 7.26 g sample of calcium phosphate reacted completely when added to an excess of aqueous nitric acid to form 38.0 cm3 of solution. Calculate the concentration
June 2014, CHEM1 (old spec), Q6(a)(ii) (2 marks): Calculate the percentage atom economy for the formation of calcium nitrate in this reaction. Give your answer to 1 decimal place. [2 marks]
June 2014, CHEM1 (old spec), Q6(b) (1 mark): Write an equation to show the reaction between calcium hydroxide and phosphoric acid to produce calcium phosphate and water. [1 mark]
June 2014, CHEM1 (old spec), Q7(c) (1 mark): Write an equation to show the formation of thallium(I) bromide from its elements. [1 mark]
June 2014, CHEM2 (old spec), Q3(a)(i) (1 mark): Write an equation for the reaction of iron with antimony sulfide to form antimony and iron(II) sulfide. [1 mark]
June 2014, CHEM2 (old spec), Q3(b)(i) (1 mark): Write an equation for this reaction. [1 mark]
June 2013, CHEM4 (old spec), Q5(a)(ii) (1 mark): Write an equation for the formation of lactic acid from sucrose and water. (1 mark)
June 2013, CHEM5 (old spec), Q8(c) (5 marks): Compound Z is a complex that contains only cobalt, nitrogen, hydrogen and chlorine. A solid sample of Z was prepared by reaction of 50 cm3 of 0.203 mol dm–3 aqu
June 2013, CHEM1 (old spec), Q5(a) (1 mark): Write an equation for the formation of aluminium chloride from its elements. (1 mark)
June 2013, CHEM1 (old spec), Q7(b) (4 marks): Zinc chloride can be prepared in the laboratory by the reaction between zinc oxide and hydrochloric acid. The equation for the reaction is ZnO + 2HCl ZnCl2 + H2
June 2013, CHEM1 (old spec), Q7(c) (4 marks): Zinc chloride can also be prepared in the laboratory by the reaction between zinc and hydrogen chloride gas. Zn + 2HCl ZnCl2 + H2 An impure sample of zinc powde
June 2013, CHEM2 (old spec), Q4(a)(i) (1 mark): Balance the equation for this reaction. 3CuS(s) + ……HNO3(aq) ……CuSO4(aq) + ……NO(g) + ……H2O(I) (1 mark)
January 2013, CHEM4 (old spec), Q3(a)(ii) (2 marks): Write an equation for the complete combustion of C17H35COOCH3 (2 marks)
January 2013, CHEM5 (old spec), Q8(d) (5 marks): In aqueous ammonia, cobalt(II) ions are oxidised to cobalt(III) ions by hydrogen peroxide. The H2O2 is reduced to hydroxide ions. Calculate the minimum volume o
January 2013, CHEM1 (old spec), Q3(d)(ii) (1 mark): Write an equation to show how OF2 reacts with steam to form oxygen and hydrogen fluoride. (1 mark)
January 2013, CHEM1 (old spec), Q4(e) (1 mark): Balance the following equation that shows how butane is used to make the compound called maleic anhydride. CH3CH2CH2CH3 + O2 C2H2(CO)2O + H2O (1 mark) →
January 2013, CHEM1 (old spec), Q5(b)(ii) (3 marks): Calculate the mass of NO2 formed from 3.00 kg of ammonia in Reaction 2 assuming an 80.0% yield. Give your answer in kilograms. (If you have been unable to calcu
January 2013, CHEM1 (old spec), Q5(c) (2 marks): Consider Reaction 3 in this process. 3NO2(g) + H2O(I) → 2HNO3(aq) + NO(g) Calculate the concentration of nitric acid produced when 0.543 mol of NO2 is reacted w
January 2013, CHEM2 (old spec), Q3(b)(i) (2 marks): Write an equation for the first stage of this extraction in which titanium(IV) oxide is converted into titanium(IV) chloride. (2 marks)
January 2013, CHEM2 (old spec), Q3(c)(i) (1 mark): In the first stage of this extraction, the FeCr2O4 is converted into Na2CrO4 Balance the equation for this reaction. FeCr2O4 + Na2CO3 + O2 Na2CrO4 + 2Fe2O3 + 8C
January 2013, CHEM2 (old spec), Q6(a) (1 mark): Write an equation for the decomposition of hydrazine into ammonia and nitrogen only. (1 mark)
June 2012, CHEM5 (old spec), Q6(d)(ii) (5 marks): Calculate the percentage by mass of FeC2O4.2H2O in the original sample. (If you have been unable to answer part (d) (i) you may assume that three moles of manga
June 2012, CHEM1 (old spec), Q5(c)(i) (4 marks): Boron trichloride is easily hydrolysed to form two different acids as shown in the following equation. BCl3(g) + 3H2O(I) H3BO3(aq) + 3HCl(aq) Calculate the conc
June 2012, CHEM1 (old spec), Q5(c)(ii) (1 mark): Boric acid (H3BO3) can react with sodium hydroxide to form sodium borate and water. Write an equation for this reaction. (1 mark)
June 2012, CHEM1 (old spec), Q5(d) (3 marks): Boron trichloride can be reduced by using hydrogen to form pure boron. BCl3(g) + 1–H2(g) B(s) + 3HCl(g) Calculate the percentage atom economy for the formation
June 2012, CHEM2 (old spec), Q1(e)(i) (1 mark): Write an equation for the overall reaction. (1 mark)
June 2012, CHEM2 (old spec), Q2(d)(ii) (1 mark): Write an equation for the complete combustion of methanol. (1 mark)
June 2012, CHEM2 (old spec), Q2(d)(iii) (1 mark): The equation for the synthesis of methanol is shown below. CO2(g) + 3H2(g) CH3OH(g) + H2O(g) Use this equation and your answer to part (d) (ii) to deduce an equ
June 2012, CHEM2 (old spec), Q3(a) (1 mark): Complete the following equation for the manufacture of phosphorus. Ca5F(PO4)3 + 9SiO2 + C 9CaSiO3 + CaF2 + CO + P (1 mark)
June 2012, CHEM2 (old spec), Q4(b)(i) (1 mark): Write an equation for the reaction of FeTiO3 with chlorine and carbon to produce iron(III) chloride (FeCl3), titanium(IV) chloride and carbon monoxide. (1 mark)
January 2012, CHEM4 (old spec), Q9(d) (1 mark): Using the molecular formula (C7H5N3O6), write an equation for the decomposition reaction that occurs on the detonation of TNT. In this reaction equal numbers of
January 2012, CHEM5 (old spec), Q7(c)(iii) (3 marks): In a titration, 6.25 cm3 of a 0.0532 mol dm–3 solution of EDTA reacted completely with the calcium ions in a 150 cm3 sample of a saturated solution of calcium h
January 2012, CHEM1 (old spec), Q3(d)(ii) (1 mark): Calculate the percentage atom economy for the formation of C6H13Cl (Mr = 120.5) in this reaction. (1 mark)
January 2012, CHEM1 (old spec), Q5(e) (1 mark): Write an equation for the reaction between silicon and nitrogen to form silicon nitride, Si3N4 (1 mark) Section B Answer all questions in the spaces provided.
January 2012, CHEM1 (old spec), Q6(a) (3 marks): In an experiment, an 8.14 g sample of lead reacted completely with a 2.00 mol dm–3 solution of nitric acid. Calculate the volume, in dm3, of nitric acid require
January 2012, CHEM1 (old spec), Q6(c)(i) (1 mark): Balance the following equation that shows this thermal decomposition. Pb(NO3)2(s) → PbO(s) + NO2(g) + O2(g) (1 mark)
January 2012, CHEM1 (old spec), Q6(c)(ii) (1 mark): Suggest one reason why the yield of nitrogen dioxide formed during this reaction is often less than expected. (1 mark)
January 2012, CHEM1 (old spec), Q6(c)(iii) (1 mark): Suggest one reason why it is difficult to obtain a pure sample of nitrogen dioxide from this reaction. (1 mark)
January 2012, CHEM2 (old spec), Q1(a)(i) (1 mark): Write an equation for the formation of SiCl4 from SiO2 using chlorine and carbon. (1 mark)
January 2012, CHEM2 (old spec), Q1(b)(i) (1 mark): Write an equation for this reaction. (1 mark)
January 2012, CHEM2 (old spec), Q1(c) (1 mark): The magnesium used to make magnesium ferrosilicon alloys is extracted from magnesium oxide using silicon. Write an equation for this reaction to produce magnesi
June 2011, CHEM5 (old spec), Q8(b)(ii) (5 marks): In a titration, 0.321 g of a moss killer reacted with 23.60 cm3 of acidified 0.0218 mol dm–3 K2Cr2O7 solution. Calculate the percentage by mass of iron in the m
June 2011, CHEM1 (old spec), Q2(a)(ii) (1 mark): Calculate the amount, in moles, of CaCO3 that reacted with the nitric acid. Give your answer to 3 significant figures. (1 mark)
June 2011, CHEM1 (old spec), Q2(a)(iii) (2 marks): Calculate the minimum mass of powdered CaCO3 that should be added to react with all of the nitric acid. Give your answer to 3 significant figures. (2 marks)
June 2011, CHEM1 (old spec), Q2(b)(ii) (1 mark): Hence calculate the amount, in moles, of oxygen produced. (1 mark)
June 2011, CHEM1 (old spec), Q7(e) (3 marks): Pentane can react with chlorine as shown in the following equation. C5H12 + Cl2 C5H11Cl + HCl Calculate the percentage atom economy for the formation of C5H11Cl
June 2011, CHEM2 (old spec), Q4(a)(i) (1 mark): Write an equation for the first stage in this extraction. (1 mark)
June 2011, CHEM2 (old spec), Q5(a)(i) (1 mark): Balance the equation for the reaction of copper with concentrated nitric acid. Cu + HNO3 Cu(NO3)2 + NO2 + H2O (1 mark)
January 2011, CHEM5 (old spec), Q7(c) (5 marks): The concentration of a hydrogen peroxide solution can be determined by titration with acidified potassium manganate(VII) solution. In this reaction the hydrogen
January 2011, CHEM1 (old spec), Q3(a)(i) (1 mark): Calculate the amount, in moles, of HCl in 33.2 cm3 of 0.150 mol dm–3 hydrochloric acid. Give your answer to 3 significant figures. (1 mark)
January 2011, CHEM1 (old spec), Q3(a)(ii) (1 mark): Calculate the amount, in moles, of M2CO3 that reacted with this amount of HCl. Give your answer to 3 significant figures. (1 mark)
January 2011, CHEM1 (old spec), Q3(a)(iii) (1 mark): Calculate the amount, in moles, of M2CO3 in the 3.44 g sample. Give your answer to 3 significant figures. (1 mark)
January 2011, CHEM1 (old spec), Q3(c) (1 mark): Suggest one possible danger when a metal carbonate is reacted with an acid in a sealed flask. (1 mark)
January 2011, CHEM1 (old spec), Q3(d)(ii) (3 marks): Calculate the mass of MgSO4 produced in this reaction assuming a 95% yield.
January 2011, CHEM2 (old spec), Q6(b)(ii) (1 mark): Balance the following equation for the reaction of serpentine with carbon dioxide. Mg3Si2O5(OH)4 + CO2 → MgCO3 + SiO2 + H2O (1 mark)
June 2010, CHEM5 (old spec), Q7(d) (6 marks): A solution of iron(II) sulfate was prepared by dissolving 10.00 g of FeSO4.7H2O (Mr = 277.9) in water and making up to 250 cm3 of solution. The solution was lef
June 2010, CHEM1 (old spec), Q1(a)(ii) (1 mark): Write an equation to show the formation of one molecule of CIF3 from chlorine and fluorine molecules. (1 mark)
June 2010, CHEM1 (old spec), Q1(e) (2 marks): An ultrasound imaging agent has the formula C4F10 It can be made by the reaction of butane and fluorine as shown in the following equation. C4H10 + 10F2 →C4F10
June 2010, CHEM1 (old spec), Q3(a)(ii) (1 mark): Calculate the total amount, in moles, of gas produced from this sample of magnesium nitrate. (1 mark)
June 2010, CHEM1 (old spec), Q3(c)(i) (1 mark): Calculate the amount, in moles, of HCl needed to react completely with the 0.0152mol sample of magnesium oxide. (1 mark) 3
June 2010, CHEM1 (old spec), Q3(c)(ii) (1 mark): This 0.0152mol sample of magnesium oxide required 32.4cm3 of hydrochloric acid for complete reaction. Use this information and your answer to part (c) (i) to ca
June 2010, CHEM2 (old spec), Q3(a)(i) (1 mark): Balance the following equation for this reaction. FeS2 + O2 Fe2O3 + SO2 (1 mark)
January 2010, CHEM4 (old spec), Q2(b)(ii) (2 marks): Calculate the concentration, in mol dm–3, of the sodium hydroxide solution used.
January 2010, CHEM5 (old spec), Q8(c) (5 marks): A chemical company has a waste tank of volume 25000dm3. The tank is full of phosphoric acid (H3PO4) solution formed by adding some unwanted phosphorus(V) oxide
January 2010, CHEM1 (old spec), Q2(a)(ii) (1 mark): Hence calculate the amount, in moles, of sodium hydroxide which reacted. (1 mark) 3
January 2010, CHEM1 (old spec), Q2(a)(iii) (1 mark): Calculate the concentration, in moldm–3, of the sodium hydroxide solution used. (1 mark)
January 2010, CHEM1 (old spec), Q2(b) (2 marks): Calculate the percentage atom economy for the production of ammonia in the reaction between ammonium sulfate and sodium hydroxide. (2 marks)
January 2010, CHEM1 (old spec), Q2(c) (1 mark): Ammonia is manufactured by the Haber Process. N2 + 3H2 2NH3 Calculate the percentage atom economy for the production of ammonia in this process. (1 mark) 2 3
January 2010, CHEM2 (old spec), Q8(a)(i) (1 mark): Balance the following equation for this first stage in which copper(I) sulfide is formed. ……CuFeS2 + ……SiO2 + ……O2 Cu2S + ……FeSiO3 + ……SO2 (1 mark)
January 2010, CHEM2 (old spec), Q8(b) (1 mark): In the second stage of this extraction, the copper(I) sulfide is converted into copper(II) oxide. This occurs by roasting the sulfide with oxygen at high temper
June 2009, CHEM1 (old spec), Q2(a)(ii) (1 mark): 2 (a) (ii) Hence calculate the amount, in moles, of nitric acid needed to react completely with this sample of magnesium. (1 mark)
June 2009, CHEM1 (old spec), Q2(a)(iii) (1 mark): 2 (a) (iii) Calculate the amount, in moles, of nitric acid originally added to this sample of magnesium. (1 mark)
June 2009, CHEM1 (old spec), Q2(a)(iv) (1 mark): 2 (a) (iv) Hence calculate the amount, in moles, of nitric acid that remains unreacted. (1 mark)
June 2009, CHEM1 (old spec), Q4(c) (2 marks): 4 (c) A reaction of hexane with chlorine is shown by the equation below. C6H14 + 2Cl2 →C6H12Cl2 + 2HCl Calculate the percentage atom economy for the formation o
June 2009, CHEM2 (old spec), Q4(d)(ii) (1 mark): 4 (d) (ii) Show how combining the equations from these two methods can lead to the 1:2 mol ratio of carbon monoxide to hydrogen required for this synthesis of m
June 2009, CHEM2 (old spec), Q10(b) (5 marks): 10 (b) Write an equation for Extraction Process 2 and an equation for Extraction Process 3. Calculate the percentage atom economy for the extraction of bromine
January 2009, CHEM1 (old spec), Q2(g) (1 mark): 2 (g) Balance the following equation which shows how AsH3 can be made. …… AsCl3 + …… NaBH4 →…… AsH3 + …… NaCl + …… BCl3 (1 mark)
January 2009, CHEM1 (old spec), Q3(a)(i) (2 marks): 3 (a) (i) Calculate the percentage atom economy for the formation of TiO2 (2 marks)
January 2009, CHEM1 (old spec), Q3(a)(ii) (1 mark): 3 (a) (ii) In view of the low atom economy of this reaction, suggest how a company can maximise its profits without changing the reaction conditions or the prod
January 2009, CHEM1 (old spec), Q3(b)(ii) (1 mark): 3 (b) (ii) Calculate the maximum amount, in moles, of TiO2 which can be formed in this experiment. (1 mark)
January 2009, CHEM1 (old spec), Q3(b)(iii) (1 mark): 3 (b) (iii) Calculate the maximum mass of TiO2 formed in this experiment. (1 mark)
January 2009, CHEM1 (old spec), Q3(b)(iv) (1 mark): 3 (b) (iv) In this experiment only 63.0 g of TiO2 were produced. Calculate the percentage yield of TiO2 (1 mark)
January 2009, CHEM1 (old spec), Q5(a)(i) (1 mark): 5 (a) (i) Calculate the amount, in moles, of HCl which reacted with 0.548 g MCO3 (1 mark)
January 2009, CHM1 (2008 spec), Q2(c) (4 marks): 2 (c) Use your answer to part (b) to calculate the mass of calcium carbide (Mr = 64.1) which reacted with the water. Hence, calculate the percentage purity of t
June 2008, CHM1 (2008 spec), Q1(c) (3 marks): 1 (c) Lead is used in lead-acid car batteries. 1 (c) (i) Balance the equation, given below, for the overall reaction which occurs when a lead-acid battery produ
June 2008, CHM1 (2008 spec), Q2(a) (3 marks): 2 (a) Oxygen may be prepared by the decomposition of hydrogen peroxide, H2O2, as shown in the equation below. 2H2O2(aq) →2H2O(l) + O2(g) A 150 cm3 sample of 2.7
June 2008, CHM1 (2008 spec), Q2(b) (4 marks): 2 (b) Phosphine, PH3, and oxygen can react to form phosphoric acid, H3PO4, as shown in the equation below. PH3 + 2O2 →H3PO4 An excess of oxygen was mixed with 1
June 2008, CHM4 (2008 spec), Q5(c) (4 marks): 5 (c) Compound G is a primary amine with molecular formula C4H11N In Reaction 2, the percentage conversion of F into G is 53.4%. 5 (c) (i) Calculate the mass of
June 2008, CHM5 (2008 spec), Q6(b) (6 marks): 6 (b) Separate aqueous solutions of potassium manganate(VII) (KMnO4) and sodium manganate(VII) (NaMnO4), each contained 1.000 g of the compound in 250 cm3 of so
June 2008, CHM6W (2008 spec), Q7 (1 mark): 7 The largest mass of silver chloride is precipitated when an excess of silver nitrate solution is added to A 25.0 cm3 of a 0.800 mol dm–3 solution of hydrochlo
June 2008, CHM6W (2008 spec), Q9 (1 mark): 9 Four possible thermal decomposition reactions of N2O5(s) are shown below. Which one of the following reactions has the largest mole fraction of oxygen gas in
June 2008, CHM6W (2008 spec), Q16 (1 mark): 16 C6H5COCl + C6H5OH →C6H5COOC6H5 + HCl (Mr = 140.5) (Mr = 198) In the reaction above, 1.20 g of the acyl chloride produced 0.800 g of the ester. The percentage
January 2008, CHM1 (2008 spec), Q2(a) (3 marks): (a) Sodium carbonate is used to neutralise a 100 cm3 sample of 1.75 mol dm–3 hydrochloric acid. (i) Calculate the number of moles of HCl in the 100 cm3 sample o
January 2008, CHM1 (2008 spec), Q2(b) (4 marks): (b) Hydrated sodium carbonate has the formula Na2CO3.10H2O (i) Calculate the percentage, by mass, of Na2CO3 in hydrated sodium carbonate. (ii) Calculate the mas
January 2008, CHM2 (2008 spec), Q3(b) (1 mark): (b) Write an equation for the complete combustion of ethanol, C2H5OH (1 mark)

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