plumiFormulae, equations and amounts of substance: Edexcel A‑Level Chemistry questions
Every Edexcel A-Level Chemistry exam question on 5 Formulae, equations and amounts of substance, 2016–2025, with its mark scheme and examiner’s report.
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Q3(b)(ii)
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Q3(a)
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Q5(a)
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Q5(a)(i)
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Q5(a)(ii)
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Q9(c)(i)
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Q9(c)(ii)
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Q9(d)(i)
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Q9(d)(ii)
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Q2(b)(i)
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Q4(a)(ii)
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Q4(a)(iii)
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Q4(b)(iii)
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Q4(b)(iv)
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Q4(b)(v)
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Q5(b)(iv)
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Q5(c)
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All 273 questions on Formulae, equations and amounts of substance, as a list
- June 2025, Paper 1, Q3(b)(ii) (2 marks): 0.041 mol of CaCO3(s) was used in the experiment. Show, by calculation, that the hydrochloric acid is in excess for Reaction 2. (2)
- June 2025, Paper 2, Q3(a) (1 mark): What is the atom economy, by mass, for the production of sodium stearate in this reaction? Substance stearin sodium hydroxide sodium stearate glycerol Molar mas
- June 2025, Paper 2, Q5(a) (4 marks): One student used 0.355 g of calcium carbonate. Calculate the minimum volume, in cm3, of 0.100 mol dm–3 hydrochloric acid that would completely react with this m
- June 2025, Paper 2, Q5(c)(i) (4 marks): If the use of heat means that the carbon dioxide gas is at a temperature of 74.0 °C, then the apparatus shown would not give a measurable result. Justify this c
- June 2025, Paper 3, Q5(a)(i) (2 marks): Show that the empirical formula and the molecular formula of R is CoN4H12Cl3 . You must show your working. (2)
- June 2025, Paper 3, Q5(a)(ii) (2 marks): 1.00 g of R was dissolved in water forming a coloured solution of the complex ion, Q. The solution was reacted with excess silver nitrate solution, forming 0.61
- June 2025, Paper 3, Q9(c)(i) (4 marks): Describe how to make the diluted solution, in Step 2. (4)
- June 2025, Paper 3, Q9(c)(ii) (5 marks): Calculate the relative formula mass of hydrated 2,5-dimethylbenzenesulfonic acid and hence deduce the value of n. (5)
- June 2025, Paper 3, Q9(d)(i) (1 mark): Give one change to this technique that would reduce the risk to this student. (1)
- June 2025, Paper 3, Q9(d)(ii) (3 marks): The student forgot to remove the funnel from the burette and during the titration five drops of acid from the funnel dripped into the burette. Explain what effe
- June 2025, AS Paper 1, Q2(b)(i) (1 mark): Sodium hydride can be made by reacting sodium metal with hydrogen. Write the equation for this reaction. State symbols are not required. (1)
- June 2025, AS Paper 1, Q2(b)(ii) (1 mark): Sodium hydride reacts with aluminium chloride to produce sodium tetrahydridoaluminate(III), NaAlH4 . Complete a balanced equation for this reaction. (1) NaH + A
- June 2025, AS Paper 1, Q4(a)(ii) (2 marks): Write an equation for the reaction that occurs with magnesium and dilute nitric acid. Include state symbols. (2)
- June 2025, AS Paper 1, Q4(a)(iii) (1 mark): The flask containing concentrated nitric acid also produced bubbles, but this time the gas was nitrogen dioxide. Water was also formed. Write an equation for th
- June 2025, AS Paper 1, Q4(b)(iii) (1 mark): The measuring cylinder was full of water before a sample of magnesium nitrate was thermally decomposed. Part of the measuring cylinder after the reaction had fi
- June 2025, AS Paper 1, Q4(b)(iv) (4 marks): The sample of magnesium nitrate had a mass of 2.966 g. Calculate the molar volume of the gas collected, giving your answer to 3 significant figures. Include uni
- June 2025, AS Paper 1, Q4(b)(v) (2 marks): Explain why three significant figures is appropriate for the answer in this calculation. (2)
- June 2025, AS Paper 1, Q5(b)(iv) (1 mark): The mass of an atom of 64 30 Zn = 1.06157 × 10–22 g. Calculate the value of the Avogadro constant using the mass of this atom and the relative isotopic mass, gi
- June 2025, AS Paper 1, Q5(c) (4 marks): Both zinc and magnesium are essential elements for human health, and both can be taken as a dietary supplement in the form of their sulfates. Hydrated zinc sulf
- June 2025, AS Paper 1, Q8 (6 marks): Ferrocene is a compound containing iron, carbon and hydrogen only. The amounts of carbon and hydrogen in a sample can be determined using the apparatus shown. 0
- June 2025, AS Paper 2, Q6(b)(i) (3 marks): Calculate the minimum mass of sodium dichromate(VI), Na2Cr2O7 , required to oxidise 0.150 mol of butan‑2‑ol. (3)
- June 2025, AS Paper 2, Q6(d)(i) (3 marks): Calculate the number of iodine molecules needed to produce 22.1 g of PI3 . [L = 6.02 × 1023 mol–1 Molar mass of phosphorus triiodide = 411.7 g mol–1] (3)
- June 2025, AS Paper 2, Q6(d)(ii) (3 marks): 11.9 g of butan‑2‑ol was reacted with excess phosphorus triiodide. 22.8 g of pure 2‑iodobutane was formed. Calculate the percentage yield of 2‑iodobutane. [Mola
- June 2024, Paper 1, Q3(d) (1 mark): What mass of potassium sulfate (K2SO4 ) would be needed to prepare 250 cm3 of a solution of concentration 0.0450 mol dm−3? The molar mass of K2SO4 is 174.3 g mo
- June 2024, Paper 1, Q10(a) (3 marks): Step 1 Dissolving the tablet. A 2.50 g vitamin C tablet was crushed and dissolved to make an aqueous solution of volume 250.0 cm3 . Describe how to make this so
- June 2024, Paper 2, Q1(d) (2 marks): The halogenoalkane, 1‑bromobutane, can be formed by the reaction of butan‑1‑ol with sodium bromide and sulfuric acid. CH3CH2CH2CH2OH + NaBr + H2SO4 → CH3CH2CH2C
- June 2024, Paper 2, Q7(b) (5 marks): Calculate the volume, in cm3, occupied by 10.0 g of chloroprene in the gaseous phase, at 80.0 °C and 205 kPa. Give your answer to an appropriate number of signi
- June 2024, Paper 2, Q7(d)(ii) (2 marks): The molar mass of a polyester is 8400 g mol–1. Calculate the number of polymer molecules in 4.25 mg of this polyester. [Avogadro constant (L) = 6.02 × 1023 mol–
- June 2024, Paper 2, Q8(d)(iv) (3 marks): Calculate the mass of Compound X required to make 15.0 g of alanine, assuming the overall yield of the synthesis is 55 %. (3)
- June 2024, Paper 3, Q3(a) (1 mark): Give a reason, with reference to the filtration in Step 3, why the formation of extremely small crystals in Step 2 would lead to a lower mass of dry barium sulf
- June 2024, Paper 3, Q3(b) (2 marks): Explain why the crystals are rinsed in Step 4. (2)
- June 2024, Paper 3, Q3(c) (3 marks): Calculate the relative formula mass of M2SO4 and hence identify M. M2SO4(aq) + BaCl2(aq) → BaSO4(s) + 2MCl(aq) [Mr of BaSO4 = 233.4] (3)
- June 2024, Paper 3, Q3(d)(i) (2 marks): Explain what effect this would have on the calculated value of the relative formula mass of M2SO4. (2)
- June 2024, Paper 3, Q3(d)(ii) (1 mark): Describe how the student should amend the procedure. (1)
- June 2024, Paper 3, Q6(a) (3 marks): When hydrolysed, 2.07 g of Q formed a carboxylic acid with a 78 % yield. Once separated, the carboxylic acid was neutralised using excess sodium hydrogencarbona
- June 2024, Paper 3, Q9(a)(i) (2 marks): State a precaution you would take in carrying out Step 3. Justify your answer. (2)
- June 2024, Paper 3, Q9(a)(ii) (2 marks): Explain what effect the omission of Step 3 would have on the titre. (2)
- June 2024, Paper 3, Q9(a)(iii) (3 marks): A mean titre of 20.60 cm3 was obtained. Calculate the concentration, in g dm–3, of tartaric acid in the white wine. C4H6O6 + 2NaOH → C4H4O6Na2 + 2H2O (3)
- June 2024, Paper 3, Q9(a)(iv) (2 marks): A student carrying out the experiment forgot to remove an air bubble from the tip of the burette before carrying out a titration. During the titration, the air
- June 2024, Paper 3, Q9(b)(i) (4 marks): A student carrying out the experiment obtained a titre of 11.80 cm3. The maximum permitted level of sulfur dioxide in white wine in the UK is 200 mg dm–3. Show
- June 2024, Paper 3, Q9(b)(ii) (2 marks): Explain how the addition of sodium hydrogencarbonate in Step 2 reduces the loss of sulfur dioxide from the flask. (2)
- June 2024, AS Paper 1, Q5(b) (4 marks): Calculate the mass of sodium chlorate(III) needed to make 5.40 g of chlorine dioxide. [Ar values: H = 1.00 O = 16.0 Na = 23.0 Cl = 35.5] (4)
- June 2024, AS Paper 1, Q5(c)(i) (2 marks): Chlorine dioxide decomposes to form chlorine and oxygen. The equation for this decomposition is shown. 2ClO2(g) → Cl2(g) + 2O2(g) Calculate the increase in volu
- June 2024, AS Paper 1, Q5(c)(ii) (3 marks): A swimming pool contains 400 m3 water. Chlorine dioxide has been suggested as a disinfectant for use in swimming pools. Calculate the mass of chlorine dioxide n
- June 2024, AS Paper 1, Q6(a)(i) (3 marks): Calculate the empirical formula of compound A. (3)
- June 2024, AS Paper 1, Q6(a)(ii) (1 mark): Calculate the molecular formula of compound A. (1)
- June 2024, AS Paper 1, Q9(c) (5 marks): A 5.00 g sample of solid potassium chlorate(V) was heated until fully decomposed. The equation for this reaction is shown. 2KClO3(s) → 2KCl(s) + 3O2(g) Calculat
- June 2024, AS Paper 2, Q1(a) (1 mark): Which piece of apparatus should be used for making a solution with a volume of exactly 250 cm3 ? (1) A burette B measuring cylinder C pipette D volumetric flask
- June 2024, AS Paper 2, Q1(b)(i) (1 mark): The diagram shows the burette before the rough titration. What is the initial burette reading for this titration? (1) 2.0 3.0 A 2.40 cm3 B 2.45 cm3 C 3.55 cm3 D
- June 2024, AS Paper 2, Q1(b)(ii) (1 mark): The final burette reading for the rough titration was 26.50 cm3. Calculate the volume of sodium hydroxide solution added in the rough titration, using your answ
- June 2024, AS Paper 2, Q1(b)(iii) (1 mark): Describe how you would use the rough titration value when carrying out the accurate titrations. (1)
- June 2024, AS Paper 2, Q1(c)(i) (1 mark): Calculate the mean titre for these accurate titrations. (1)
- June 2024, AS Paper 2, Q1(c)(ii) (1 mark): Calculate the number of moles of sodium hydroxide in the mean titre. (1)
- June 2024, AS Paper 2, Q1(c)(iii) (3 marks): The mass of H2A used to make up 250 cm3 of solution in the experiment was 1.54 g. Calculate the relative molecular mass of H2A and therefore the value of n in H
- June 2023, Paper 1, Q10(c)(ii) (1 mark): The concentration of oxygen in water is often expressed in parts per million (ppm), where 1 ppm equals 1 g of solute dissolved in 1 × 106 g of solvent. Calculat
- June 2023, Paper 2, Q3(b) (2 marks): 9.90 g of a gaseous organic compound, Y, occupies a volume of 5.40 dm3 at room temperature and pressure (r.t.p.). Calculate the molar mass of the compound Y. [m
- June 2023, Paper 2, Q3(c) (4 marks): A quantity of a volatile organic liquid, Z, is placed in a 60.0 cm3 flask and heated to 95.0°C. When all the liquid has vaporised, the flask is sealed. Mass of
- June 2023, Paper 2, Q4(a) (4 marks): A 2.50 g sample of a hydrocarbon gave 7.59 g of carbon dioxide on complete oxidation. Calculate the empirical formula of the hydrocarbon. (4)
- June 2023, Paper 2, Q9(b) (5 marks): An organic compound, Q, contains carbon, hydrogen and nitrogen only. When a 1.19 g sample of the compound was heated with sodium hydroxide solution, all of the
- June 2023, Paper 3, Q3(d)(vi) (2 marks): Calculate the volume of 2.759 × 1020 molecules of alkene gas at room temperature and pressure (r.t.p.). (2)
- June 2023, Paper 3, Q7(a)(i) (1 mark): Describe how to remove an air bubble from the tip of the pipette. (1)
- June 2023, Paper 3, Q7(a)(ii) (1 mark): Calculate the maximum volume that would be obtained by using a 25.0 cm3 pipette twice to measure a total volume of 50.0 cm3. The uncertainty in each 25.0 cm3 pi
- June 2023, Paper 3, Q7(a)(iii) (2 marks): Compare the percentage uncertainty in using a 25.0 cm3 pipette twice with using a 50.0 cm3 pipette once to measure 50.0 cm3 of water. The uncertainty in the 50.
- June 2023, Paper 3, Q7(b)(i) (1 mark): State whether or not a 100 cm3 measuring cylinder is suitable to measure this volume of buffer solution. Justify your answer. (1)
- June 2023, Paper 3, Q7(d)(i) (1 mark): Name the process needed before titrating the sample of boiled water. (1)
- June 2023, Paper 3, Q7(d)(ii) (6 marks): The mean titre of 0.0100 mol dm–3 EDTA4– with a 50.0 cm3 water sample before boiling was 12.80 cm3. After boiling the mean titre was 5.15 cm3. There is a 1 : 1
- June 2023, AS Paper 1, Q2(a)(i) (1 mark): Give the reason why the term relative formula mass is used, rather than relative molecular mass, when discussing K2Mg(SO4)2.6H2O. (1)
- June 2023, AS Paper 1, Q2(a)(ii) (1 mark): Give the reason why relative formula mass has no mathematical units. (1)
- June 2023, AS Paper 1, Q2(a)(iii) (1 mark): What is the relative formula mass of K2Mg(SO4)2.6H2O? Use the Periodic Table as a source of data. (1) A 206.0 B 322.7 C 402.7 D 595.3
- June 2023, AS Paper 1, Q2(a)(iv) (1 mark): Calculate the amount of substance, in mol, in 25.0 g of K2Mg(SO4)2.6H2O. (1)
- June 2023, AS Paper 1, Q3(a)(v) (2 marks): Chromium reacts with iodine. The only product contains 12.0 % chromium by mass. Calculate the empirical formula of the chromium iodide formed. You must show you
- June 2023, AS Paper 1, Q4(b) (4 marks): The equation for the reaction to produce chlorine is shown. 2KMnO4 + 8HCl → 3Cl2 + 2KCl + 2MnO2 + 4H2O The concentration of the hydrochloric acid is 11.5 mol dm
- June 2023, AS Paper 1, Q7(c) (1 mark): A saturated aqueous calcium hydroxide solution contains 17.3 g in 10.0 dm3 of solution. Under these conditions the calcium hydroxide is fully dissociated into i
- June 2023, AS Paper 1, Q8(a)(i) (2 marks): Identify a change to the acid in Step 1 that would reduce the volume of gas lost between Steps 5 and 6. Justify your answer. (2)
- June 2023, AS Paper 1, Q8(a)(ii) (2 marks): Identify a change to the procedure in Steps 5 and 6 that would prevent loss of gas. (2)
- June 2023, AS Paper 1, Q8(b) (2 marks): A second source of inaccuracy results from the significant solubility in water of carbon dioxide. Give two improvements which together prevent this problem. (2)
- June 2023, AS Paper 1, Q8(c)(i) (3 marks): Use the graph to find the molar volume of carbon dioxide, in dm3. You must show your working on the graph. [Assume molar mass of CaCO3 = 100 g mol–1] (3)
- June 2023, AS Paper 1, Q8(c)(ii) (3 marks): The procedure was carried out at a temperature of 22 °C and a pressure of 1.01 × 105 Pa. Calculate the theoretical molar volume, giving units with your answer.
- June 2023, AS Paper 2, Q2(b)(ii) (2 marks): Calculate the maximum mass, in grams, of chloromethane produced when 7.00 g of chlorine gas reacts completely with excess methane. [Molar mass of CH3Cl = 50.5 g
- June 2023, AS Paper 2, Q2(b)(iv) (3 marks): Further substitution of chloromethane can occur, producing dichloromethane, which is a liquid at room temperature. Calculate the maximum volume, in cm3, of dich
- June 2023, AS Paper 2, Q2(c)(i) (4 marks): Calculate the maximum volume, in m3, of carbon dioxide gas produced in an engine by the complete combustion of 1.00 kg of C12H26 at 200 °C, at a pressure of 6.0
- June 2022, Paper 1, Q2(d) (2 marks): An experiment was carried out to determine the molar volume of hydrogen at room temperature. 0.035 g of magnesium was added to excess hydrochloric acid and 32 c
- June 2022, Paper 2, Q4(a)(i) (4 marks): Calculate the volume of nitrogen gas, in cm3, in one packet of crisps. [R = 8.31 J mol–1 K–1] (4)
- June 2022, Paper 2, Q4(a)(ii) (1 mark): Give a possible reason why nitrogen gas and not air is used in packets of crisps. (1)
- June 2022, Paper 2, Q5(b) (3 marks): Calculate how many more molecules there are in 5.00 cm3 of water compared to 5.00 cm3 of ice. (3)
- June 2022, Paper 2, Q6(c)(v) (3 marks): Another student used the correct apparatus for this oxidation. 1.50 g of propan‑1‑ol produced 0.609 g of propanal. Calculate the percentage yield of propanal by
- June 2022, Paper 3, Q2(a)(iii) (3 marks): Give the reasons for carrying out Steps 3 and 4 of the procedure, referring particularly to the words in bold. (3)
- June 2022, Paper 3, Q2(b) (2 marks): The percentage yield of this reaction is 70.0 %. Give two possible reasons, other than an incomplete reaction, why the yield is less than 100 %. (2)
- June 2022, Paper 3, Q3(c)(i) (2 marks): The first student carried out the experiment but forgot to use the lid. Explain how this mistake would affect the calculated value of n. (2)
- June 2022, Paper 3, Q3(c)(ii) (2 marks): The second student carried out the experiment but heated the apparatus for only one minute. Explain how this mistake would affect the calculated value of n. (2)
- June 2022, Paper 3, Q3(c)(iii) (3 marks): In an accurate experiment, Y is found to consist of 71.9 % K2CO3 by mass. Calculate the value of n. (3)
- June 2022, Paper 3, Q6(a) (4 marks): When burned in excess oxygen, 1.879 g of Q formed 4.594 g of carbon dioxide and 1.879 g of water. Show that the empirical formula of Q is C4H8O. (4)
- June 2022, Paper 3, Q9(a)(ii) (2 marks): A student did not notice an air bubble in the tip of the burette before carrying out one of their accurate titrations. During this titration, the air bubble esc
- June 2022, Paper 3, Q10(a)(ii) (1 mark): Write the ionic equation for the reaction that takes place during Step 4. State symbols are not required. (1)
- June 2022, AS Paper 1, Q4(d) (4 marks): 1.00 g of a different hydrocarbon, W, was burnt in oxygen. Analysis of the combustion products showed that complete combustion produced 3.14 g of carbon dioxide
- June 2022, AS Paper 1, Q7(c)(iii) (4 marks): The equation for the thermal decomposition of sodium nitrate is different from that for lithium nitrate. NaNO3(s) → NaNO2(s) + ½O2(g) The gas produced is collec
- June 2022, AS Paper 1, Q7(c)(iv) (1 mark): State one reason why the experimental gas volume may differ from the calculated theoretical volume. Assume that no gas escapes and measurements have been made a
- June 2022, AS Paper 1, Q8(a) (2 marks): When hydrogen gas and chlorine gas are mixed and passed over a hot platinum catalyst, hydrogen chloride gas is formed. The equation for this reaction is H2(g) +
- June 2022, AS Paper 1, Q8(b)(iv) (5 marks): Describe an experiment to enable you to accurately determine the concentration of an approximately 1 mol dm–3 solution of hydrochloric acid, using a solution of
- June 2022, AS Paper 1, Q8(c)(ii) (4 marks): A student reacted 5.0 cm3 of 5.0 mol dm–3 hydrochloric acid with an excess of manganese(IV) oxide. 70 cm3 of chlorine gas was produced. The teacher said the exp
- June 2022, AS Paper 1, Q8(d)(ii) (3 marks): Calculate the atom economy, by mass, of sodium chlorate(V) in this reaction. (3)
- June 2022, AS Paper 1, Q9(a) (2 marks): Water gas is produced by passing steam over white hot coke. The equation for the reaction is shown. H2O(g) + C(s) → CO(g) + H2(g) Calculate the total mass of pr
- June 2022, AS Paper 2, Q4(a)(iii) (2 marks): Calculate the number of moles of ethanoic acid, with a concentration of 1.10 mol dm−3 , added at the end‑point of the reaction. (2)
- June 2022, AS Paper 2, Q6(e) (4 marks): 11.6 cm3 of 2‑chloro‑2‑methylpropane was collected from 12.0 g of 2‑methylpropan‑2‑ol. Calculate the percentage yield using the data in the table. (4) Density M
- November 2021, Paper 2, Q1 (1 mark): What is the total number of ions in 26.4 g of ammonium sulfate, (NH4)2SO4? [Molar mass of (NH4)2SO4 = 132 g mol−1 Avogadro constant = 6.0 × 1023 mol−1] A 4.0 ×
- November 2021, Paper 2, Q2 (1 mark): The equation for the complete combustion of butane is 2C4H10(g) + 13O2(g) → 8CO2(g) + 10H2O(l) What is the minimum volume of oxygen, at room temperature and pre
- November 2021, Paper 2, Q4(d) (4 marks): A sample of pent-1-ene, with a mass of 1.33 g, is warmed to 60 °C in a sealed container. The volume of the container is 500 cm3. Calculate the pressure inside t
- November 2021, Paper 2, Q6(b) (2 marks): Carbon monoxide can be made by the thermal decomposition of sodium ethanedioate. Na2C2O4 → Na2CO3 + CO Calculate the atom economy, by mass, for the production o
- November 2021, Paper 2, Q8(a) (4 marks): A sample of Y with a mass of 1.98 g was burned completely in excess oxygen. The reaction formed 2.51 g of carbon dioxide, CO2 , and 0.69 g of water, H2O. Use th
- November 2021, Paper 2, Q8(b) (5 marks): A solution was prepared using 4.34 g of the dicarboxylic acid Y made up to a volume of 250 cm3 with distilled water. A 25.0 cm3 sample of this solution was then
- November 2021, Paper 2, Q9(b) (3 marks): Calculate the minimum mass of phenol needed to synthesise 1.00 kg of paracetamol. [Mr values: paracetamol = 151.0 phenol = 94.0] (3)
- November 2021, Paper 3, Q7(a)(ii) (2 marks): Show, by calculation, that the hydrochloric acid is in excess. You must show your working. NaHCO3(s) + HCl(aq) → NaCl(aq) + H2O(l) + CO2(g) (2)
- November 2021, AS Paper 1, Q2(a) (5 marks): Sodium carbonate forms a number of hydrates with the general formula Na2CO3.xH2O. A 250 cm3 standard solution of one of these hydrates contained 10.0 g of the c
- November 2021, AS Paper 1, Q2(b)(i) (1 mark): What is the colour change at the end-point of the reaction? (1) From To A red orange B red yellow C yellow orange D yellow red
- November 2021, AS Paper 1, Q2(b)(ii) (1 mark): State why the value for the total titre in Titration 1 should not be used to calculate the mean titre. (1)
- November 2021, AS Paper 1, Q2(b)(iii) (1 mark): Calculate the mean titre. (1)
- November 2021, AS Paper 1, Q2(b)(iv) (4 marks): Calculate the relative formula mass, Mr , of the hydrated sodium carbonate, Na2CO3.xH2O. The equation for the reaction in the titration is Na2CO3 + 2HCl → 2NaCl
- November 2021, AS Paper 1, Q2(c)(i) (1 mark): Calculate the relative formula mass of anhydrous sodium carbonate, Na2CO3 . (1)
- November 2021, AS Paper 1, Q2(c)(ii) (1 mark): Calculate the number of molecules of water of crystallisation, x, for this hydrated sodium carbonate, Na2CO3.xH2O. (1)
- November 2021, AS Paper 1, Q2(d) (3 marks): Sodium carbonate is manufactured from sodium chloride in a two-stage process. NaCl + NH3 + CO2 + H2O → NaHCO3 + NH4Cl 2NaHCO3 → Na2CO3 + H2O + CO2 Calculate the
- November 2021, AS Paper 1, Q3(a)(i) (1 mark): Write the equation for this reaction. State symbols are not required. (1)
- November 2021, AS Paper 1, Q4(b) (5 marks): Compound X is an oxide of sulfur. A gaseous sample of 0.318 g of X occupied a volume of 132 cm3 at a temperature of 420 K and pressure of 105 kPa. The number of
- November 2021, AS Paper 1, Q7(b) (1 mark): What is the percentage by mass of strontium in strontium nitrate? (1) A 38.0 % B 41.4 % C 58.6 % D 74.5 %
- November 2021, AS Paper 2, Q4(a) (1 mark): Write an equation, including state symbols, for this reaction. (1)
- November 2021, AS Paper 2, Q4(c)(i) (2 marks): Calculate the minimum volume of water needed to convert 10.00 g of CaSO4·½H2O into CaSO4·2H2O. (2)
- November 2021, AS Paper 2, Q8(c)(ii) (4 marks): In an experiment, 10.0 cm3 of cyclohexanol was converted to cyclohexene with a 63.0 % yield. Molar mass / g mol–1 Density / g cm–3 Compound cyclohexanol 100 0.9
- November 2021, AS Paper 2, Q9(a)(iii) (1 mark): What is the percentage atom economy, by mass, for ammonia in the forward reaction? N2(g) + 3H2(g) 2NH3(g) (1) A 17.6 % B 50.0 % C 82.4 % D 100 %
- October 2020, Paper 1, Q5(b)(ii) (5 marks): Use the experimental data to calculate the value for x in the formula Mg(NO3)2.xH2O . You must show all your working. (5)
- October 2020, Paper 2, Q2(d)(ii) (2 marks): Calculate the number of molecules in 70.0 g of but-1-ene. [Avogadro constant = 6.02 × 1023 mol−1] (2)
- October 2020, Paper 2, Q3(b) (3 marks): Potassium bromate decomposes on heating. 2KBrO3 → 2KBr + 3O2 Calculate the maximum volume of oxygen, in dm3, measured at room temperature and pressure (r.t.p.),
- October 2020, Paper 2, Q5(d)(i) (1 mark): Ethane burns in excess oxygen. 2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(g) All gas volumes are measured at the same temperature and pressure when water is a gas. Wh
- October 2020, Paper 2, Q5(d)(ii) (3 marks): A combustion experiment was carried out using conditions under which water was a liquid. A cyclic hydrocarbon, CxHy , was mixed with excess oxygen and ignited
- October 2020, Paper 2, Q5(f) (4 marks): Limonene is obtained from the oil in lemon peel and it is the only alkene present. 0.500 g of the oil reacted with exactly 30.6 cm3 of a solution of bromine di
- October 2020, Paper 3, Q3(a)(i) (2 marks): Describe how you would ensure that all the sodium hydroxide was transferred to the volumetric flask. (2)
- October 2020, Paper 3, Q3(a)(ii) (1 mark): A student adds deionised water above the mark and shakes the flask. State why the procedure has to be restarted rather than using a teat pipette to remove the e
- October 2020, Paper 3, Q3(b)(i) (2 marks): Student 1 used a funnel to pour sodium hydroxide solution into the burette. Give two steps needed before the student takes the initial burette reading. (2)
- October 2020, Paper 3, Q3(b)(ii) (1 mark): Student 2 cleaned the burette by rinsing it with deionised water immediately before filling it with the sodium hydroxide solution. Give the effect, if any, on t
- October 2020, Paper 3, Q3(d)(i) (1 mark): Complete the table. (1)
- October 2020, Paper 3, Q3(d)(ii) (1 mark): The low titre for titration 4 was queried by the teacher. The student had wanted to refill the burette and continue the titration but had been told the measurem
- October 2020, Paper 3, Q3(e) (5 marks): The teacher carried out the experiment and obtained the following results. Mass of sodium hydroxide used to make 250.0 cm3 solution = 3.80 g Volume of ethanoic
- October 2020, Paper 3, Q4(a) (2 marks): Calculate the mass of 0.0250 mol of hydrated copper(II) sulfate, CuSO4.5H2O . (2)
- October 2020, Paper 3, Q5(g) (3 marks): Benzoic acid can be purified in Step 8 because of its high solubility in hot water and low solubility in cold water. Calculate the maximum number of benzoic aci
- October 2020, Paper 3, Q6(a) (2 marks): Write the equation for the complete combustion of phenol. State symbols are not required. (2)
- October 2020, Paper 3, Q6(b)(i) (3 marks): Calculate the percentage composition by mass of carbon in both phenylmethanol and benzoic acid. (3)
- October 2020, AS Paper 1, Q6(a) (1 mark): What is the percentage by mass of copper in pure malachite? (1) A 40.3% B 51.4% C 57.5% D 67.9%
- October 2020, AS Paper 1, Q6(d)(i) (5 marks): When malachite is heated to approximately 300 °C, water, carbon dioxide and copper(II) oxide are formed. The equation for this decomposition is Cu2CO3(OH)2 → 2C
- October 2020, AS Paper 1, Q6(d)(ii) (1 mark): The gas was collected in a gas syringe with a stated accuracy of ± 0.5 cm3. Calculate the percentage uncertainty in the volume of gas collected. (1)
- October 2020, AS Paper 1, Q6(d)(iii) (3 marks): Malachite ore is a mixture of malachite and rock. A 0.810 g sample of malachite ore was thermally decomposed, producing 0.571 g of copper(II) oxide. Calculate t
- October 2020, AS Paper 2, Q1(b)(i) (3 marks): A different refrigerant contains 34.0% chlorine and 54.5% fluorine by mass, with the remainder carbon. Calculate the empirical formula of this compound. (3)
- October 2020, AS Paper 2, Q5(c)(i) (3 marks): To determine the extent of unsaturation of an oil, 0.250 g of the oil was treated with 25.00 cm3 of a 0.100 mol dm−3 ICl solution. Unreacted ICl reacted with ex
- October 2020, AS Paper 2, Q5(c)(ii) (2 marks): Unsaturation in oils is measured using a scale called ‘Iodine number’. This is the mass of iodine which will react with 100 g of the oil. Because iodine adds ve
- June 2019, Paper 1, Q10(a)(ii) (1 mark): Calculate the number of sulfur dioxide molecules present in this equilibrium mixture. (1)
- June 2019, Paper 2, Q2(c)(ii) (2 marks): Calculate the atom economy by mass for the formation of 1-bromopropane in the reaction in (c). (2)
- June 2019, Paper 2, Q4(a) (2 marks): Calculate the mass of carbon in 2.34 g of methyl cinnamate. (2)
- June 2019, Paper 2, Q5(b) (4 marks): A student carried out an experiment to determine the molar mass of xylene. The student's sample of xylene vapour had a mass of 0.271 g. At a temperature of 165°
- June 2019, Paper 3, Q7(b)(i) (3 marks): Deduce, by calculation, the value of z, to the nearest whole number, in the formula KH3(C2O4)y. zH2O. You must use the data from Experiment 2 and your value of
- June 2019, Paper 3, Q7(b)(ii) (5 marks): A third student carried out Experiment 2 and calculated a value of z that was lower than expected. This student evaluated the experiment and gave two suggestion
- June 2019, Paper 3, Q8(b)(iv) (2 marks): The volume of 1-bromobutane collected was 12.0 cm3. Calculate the number of molecules of 1-bromobutane produced in this experiment. Give your answer to an appro
- June 2019, Paper 3, Q9(a)(iii) (4 marks): In an experiment, the crystals are filtered, weighed and the percentage yield calculated. Student 1 obtained a yield of 102.6%. Student 2 obtained a yield of 56
- June 2019, Paper 3, Q10(a)(ii) (5 marks): On combustion in dry oxygen, 3.36 g of D produced 0.72 g of water and 5.28 g of carbon dioxide. This sample of D also contained 0.56 g of nitrogen. Use these da
- June 2019, AS Paper 1, Q1 (1 mark): How many ions are present in 306 g of aluminium oxide, Al2O3 ? [Avogadro constant = 6.02 q 1023 mol−1 Molar mass of Al2O3 = 102 g mol−1 ] A 6.02 q 1023 B 1.81 q
- June 2019, AS Paper 1, Q5(a) (1 mark): What is the percentage by mass of iron in anhydrous iron(II) sulfate, FeSO4, to 3 significant figures? (1) A 21.3% B 35.1% C 36.7% D 53.8%
- June 2019, AS Paper 1, Q5(c) (1 mark): Mohr’s salt is another compound containing iron(II) ions. It has the formula (NH4)2Fe(SO4)2. 6H2O. What is the molar mass, in g mol−1, of Mohr’s salt? (1) A 392
- June 2019, AS Paper 1, Q7(a) (2 marks): Write an equation for the reaction of magnesium with hydrochloric acid. Include state symbols. (2)
- June 2019, AS Paper 1, Q7(b)(i) (1 mark): A measuring cylinder was used to measure the 10.0 cm3 of dilute hydrochloric acid in Step 1. The uncertainty for a volume measurement is ± 0.5 cm3. Calculate th
- June 2019, AS Paper 1, Q7(b)(ii) (3 marks): Determine which reactant is in excess by calculating the number of moles of magnesium and of hydrochloric acid used in the experiment. (3)
- June 2019, AS Paper 1, Q7(b)(iii) (1 mark): Calculate the maximum number of moles of gas that could be produced, using your answers to (a) and (b)(ii). (1)
- June 2019, AS Paper 1, Q7(b)(iv) (4 marks): Under the conditions of the experiment, the temperature was 23°C and the pressure 98 000 Pa. Calculate the maximum volume of gas, in cm3, that could be produced
- June 2019, AS Paper 1, Q7(c)(i) (2 marks): Deduce two possible reasons why the volume of gas collected in the experiment was smaller than that calculated in (b)(iv). (2)
- June 2019, AS Paper 1, Q7(c)(ii) (2 marks): Describe two changes to the procedure that would enable the volume of gas collected to be closer to that calculated in (b)(iv). (2)
- June 2019, AS Paper 1, Q9(c) (3 marks): Chlorine gas, Cl2 , can be dissolved in swimming pool water to disinfect it. An Olympic-sized swimming pool contains about 2500 m3 of water. The chlorine conten
- June 2019, AS Paper 1, Q9(f) (3 marks): Calcium chlorate(I), Ca(ClO)2 , can be used to disinfect drinking water. The concentration of chlorate(I) ions required to disinfect water is about 5.6 × 10–6 m
- June 2019, AS Paper 2, Q5(c) (2 marks): Calculate the percentage of 1-bromobutane which was converted to but-1-ene. [Molar volume of a gas at r.t.p. = 24 000 cm3 mol–1] (2)
- June 2019, AS Paper 2, Q5(d) (2 marks): Before cooling, the volume of but-1-ene in the gas syringe was 24.0 cm3. Calculate the temperature of the gas in the syringe before it cooled. [Assume no loss f
- June 2019, AS Paper 2, Q6(a)(i) (1 mark): Name the piece of apparatus used to measure 25.0 cm3 of wine. (1)
- June 2019, AS Paper 2, Q6(a)(ii) (1 mark): To improve the accuracy, the burette should be rinsed. State what should be used. (1)
- June 2019, AS Paper 2, Q6(a)(iii) (1 mark): What is the colour change at the end-point? (1) A from orange to yellow B from red to orange C from colourless to pink D from pink to colourless
- June 2019, AS Paper 2, Q6(a)(iv) (1 mark): State what is meant by the term ‘concordant results’ as applied to a titration experiment. (1)
- June 2019, AS Paper 2, Q6(a)(v) (5 marks): Calculate the percentage of ethanol that has oxidised, given that one mole of ethanol forms one mole of ethanoic acid. Give your answer to an appropriate number
- June 2019, AS Paper 2, Q6(a)(vi) (1 mark): Deduce why this method would not be effective for the analysis of the acid content of a red wine. (1)
- June 2019, AS Paper 2, Q6(b) (3 marks): The ethanol content of alcoholic drinks is usually measured as the percentage of alcohol by volume (ABV). ABV = Volume of ethanol in a solution × 100 Total volu
- June 2019, AS Paper 2, Q7(a) (1 mark): What is the percentage by mass of each element in C4H8O? (1) Percentage carbon Percentage hydrogen Percentage oxygen 66.67 11.11 22.22 A 60.00 20.00 20.00 B 41.
- June 2018, Paper 1, Q7(a) (1 mark): Boric acid can be prepared by reacting borax, Na2B4O7.10H2O, with hydrochloric acid. Write the equation for this reaction. State symbols are not required. (1)
- June 2018, Paper 2, Q4(a)(i) (1 mark): Write the equation for this decomposition of sodium azide. State symbols are not required. (1)
- June 2018, Paper 2, Q4(a)(ii) (4 marks): In the reaction in (a)(i), a typical airbag is inflated by about 67 dm3 of gas. Calculate the minimum mass of sodium azide, in grams, needed to produce this vol
- June 2018, Paper 2, Q7(e) (2 marks): Calculate the percentage by mass of carbon in phenylethene, giving your answer to an appropriate number of significant figures. (2)
- June 2018, Paper 2, Q8(b)(ii) (1 mark): What is the mass, in grams, of 4-nitrophenol produced from 0.94 g of phenol if the yield of this isomer is 15%? (1) A 0.14 B 0.21 C 0.68 D 1.39
- June 2018, Paper 3, Q3(a) (1 mark): This question is about the identification of a Group 2 carbonate. A chemistry teacher found a bottle containing lumps of a white solid. The original label was m
- June 2018, Paper 3, Q3(b) (1 mark): This question is about the identification of a Group 2 carbonate. A chemistry teacher found a bottle containing lumps of a white solid. The original label was m
- June 2018, Paper 3, Q3(c) (4 marks): This question is about the identification of a Group 2 carbonate. A chemistry teacher found a bottle containing lumps of a white solid. The original label was m
- June 2018, Paper 3, Q3(d)(i) (2 marks): This question is about the identification of a Group 2 carbonate. A chemistry teacher found a bottle containing lumps of a white solid. The original label was m
- June 2018, Paper 3, Q3(d)(ii) (1 mark): This question is about the identification of a Group 2 carbonate. A chemistry teacher found a bottle containing lumps of a white solid. The original label was m
- June 2018, Paper 3, Q3(e)(ii) (3 marks): This question is about the identification of a Group 2 carbonate. A chemistry teacher found a bottle containing lumps of a white solid. The original label was m
- June 2018, Paper 3, Q3(f) (1 mark): This question is about the identification of a Group 2 carbonate. A chemistry teacher found a bottle containing lumps of a white solid. The original label was m
- June 2018, Paper 3, Q3(g) (2 marks): This question is about the identification of a Group 2 carbonate. A chemistry teacher found a bottle containing lumps of a white solid. The original label was m
- June 2018, Paper 3, Q6(b) (2 marks): The students decide to carry out an acid-base titration to obtain further information about compound X. Each student uses solid sodium hydroxide, NaOH, to prepa
- June 2018, Paper 3, Q6(c)(i) (2 marks): Each of the students makes up 250.0 cm3 of 0.140 mol dm−3 sodium hydroxide solution in a volumetric flask and titrates this solution with the same solution of X
- June 2018, Paper 3, Q6(c)(ii) (2 marks): Explain how, if at all, Student C’s use of a wet conical flask affects the value of the titre. (2)
- June 2018, Paper 3, Q6(c)(iii) (3 marks): Student A uses three pieces of apparatus to measure volumes in this experiment. • The burette has an uncertainty of ±0.05 cm3 for each volume reading • The volu
- June 2018, Paper 3, Q6(d)(ii) (2 marks): Deduce the value that would have been obtained for the mean titre if the structural formula of X had been structure 2. Justify your answer. (2)
- June 2018, AS Paper 1, Q3(a) (1 mark): Select the most appropriate piece of apparatus to measure the 25.0 cm3 of sulfuric acid. (1) A burette B measuring cylinder C pipette D volumetric flask
- June 2018, AS Paper 1, Q3(b) (1 mark): What is the colour of the solution when neutralisation has just occurred? (1) A colourless B orange C pale pink D red
- June 2018, AS Paper 1, Q3(c)(i) (2 marks): Complete the table of results for titration number 1, using the diagrams to find the initial and final burette readings. (2) 4 32 5 33 Initial reading Final rea
- June 2018, AS Paper 1, Q3(c)(ii) (1 mark): The best value for the mean titre of this reaction is (1) A 27.00 cm3 B 27.15 cm3 C 27.25 cm3 D 27.30 cm3
- June 2018, AS Paper 1, Q3(c)(iii) (3 marks): Calculate the concentration, in mol dm−3, of the potassium hydroxide solution, giving your answer to an appropriate number of significant figures. (3)
- June 2018, AS Paper 1, Q4(c) (4 marks): Heating the hydrated compound results in the formation of the anhydrous ionic solid MN by the following reaction: MN.xH2O(s) → MN(s) + xH2O(g) Heating a sample
- June 2018, AS Paper 1, Q5(a)(i) (2 marks): Describe two observations that the student might make which show that the reaction in Step 1 has finished. (2)
- June 2018, AS Paper 1, Q5(a)(ii) (1 mark): State the purpose of the filtration in Step 3. (1)
- June 2018, AS Paper 1, Q5(a)(iii) (2 marks): Explain the use of a small volume of ice-cold water in Step 6. (2)
- June 2018, AS Paper 1, Q5(b) (5 marks): The student obtained a mass of 14.26 g of hydrated crystals. Assuming that the percentage yield is 100%, use the information in the procedure to give a possible
- June 2018, AS Paper 1, Q5(c)(iii) (2 marks): Calculate the actual percentage yield of the reaction, which produced 14.26 g of crystals. Give your answer to two significant figures. (2)
- June 2018, AS Paper 1, Q8(a)(i) (1 mark): Select the correct equation for this reaction. (1) A Na(s) + F(g) → NaF(s) B 2Na(s) + F2(g) → 2NaF(s) C Na(s) + F2(g) → NaF2(s) D 2Na(s) + F(g) → Na2F(s)
- June 2018, AS Paper 2, Q2(a)(i) (3 marks): Calculate the volume of one mole of an ideal gas, A, at 60 °C and 500 kPa pressure. Give your answer to two significant figures and include units. [The ideal ga
- June 2018, AS Paper 2, Q2(a)(ii) (2 marks): At room temperature and pressure (r.t.p) another gas B, with formula XH3 , has a density of 1.42 g dm−3. Calculate the molar mass of the gas XH3 and deduce the
- June 2018, AS Paper 2, Q2(b)(i) (5 marks): Calculate the moles of hydrochloric acid and the moles of sodium carbonate used in this experiment. Use your answers to decide which reactant is in excess. Calc
- June 2018, AS Paper 2, Q2(b)(ii) (2 marks): The actual volume of carbon dioxide collected was less than calculated. Give two reasons for this. (2)
- June 2018, AS Paper 2, Q3(b)(ii) (2 marks): Calculate the atom economy by mass for the formation of NO in this reaction. Give your answer to an appropriate number of significant figures. (2)
- June 2018, AS Paper 2, Q6(b) (6 marks): Butane-1,4-diol can be oxidised to form butanedioic acid. The molecular formula of butanedioic acid is C4H6O4 and it is a solid at room temperature. Describe ho
- June 2018, AS Paper 2, Q7(a)(i) (2 marks): In the appropriate row, tick () those titre values that should be used to find the mean, and use these titres to calculate it. Write the value of the mean titr
- June 2018, AS Paper 2, Q7(a)(ii) (2 marks): Ethanedioic acid is a weak acid. Name a suitable indicator for this titration and state the colour change at the end-point. (2) Name of indicator Colour change
- June 2018, AS Paper 2, Q7(a)(iii) (4 marks): The equation for the reaction of ethanedioic acid with sodium hydroxide is C2H2O4 + 2NaOH → C2O4Na2 + 2H2O Calculate the concentration of the sodium hydroxide s
- June 2018, AS Paper 2, Q7(b)(i) (2 marks): Calculate the percentage uncertainties for titre 4, and the pipette volume. (2)
- June 2018, AS Paper 2, Q7(b)(ii) (1 mark): Which of the following changes would halve the percentage uncertainty in the volume of liquid measured by the burette? (1) A halve the acid concentration and ha
- June 2017, Paper 2, Q4(a)(i) (3 marks): Using the Ideal Gas Equation, calculate the mass of nitrogen gas, in grams, present in the car tyre under these conditions. Give your answer to an appropriate n
- June 2017, Paper 2, Q4(a)(ii) (1 mark): During a car journey, the tyres become warm. Use the Ideal Gas Equation to deduce the effect that this has on the pressure in the tyres. (1)
- June 2017, Paper 2, Q5(c) (1 mark): In the UK, the exhaust emissions of a petrol-fuelled vehicle must be less than 1.00 g of carbon monoxide per kilometre. What is the maximum number of carbon mon
- June 2017, Paper 2, Q7(d) (2 marks): A tablet with a total mass of 500 mg contained 3.10 × 10−3 mol of paracetamol. Calculate the percentage by mass of paracetamol in the tablet, quoting your answe
- June 2017, Paper 3, Q2(c)(iii) (2 marks): Solid sodium carbonate is added to the distillate. The sodium carbonate disappears and fizzing occurs. Write an equation, including state symbols, for the react
- June 2017, Paper 3, Q2(f)(ii) (2 marks): Calculate the mass of 3-methylbutan-2-ol that the student uses at the start of the preparation. (2)
- June 2017, Paper 3, Q6(g) (1 mark): A student carried out an investigation to determine the value of x in hydrated magnesium nitrate(III), Mg(NO2)2•xH2O, using three different methods. Method 1 •
- June 2017, Paper 3, Q6(h) (2 marks): A student carried out an investigation to determine the value of x in hydrated magnesium nitrate(III), Mg(NO2)2•xH2O, using three different methods. Method 1 •
- June 2017, AS Paper 1, Q6(a)(i) (1 mark): Write the equation for this reaction. State symbols are not required. (1)
- June 2017, AS Paper 1, Q6(b) (6 marks): Aluminium also reacts directly with chlorine to form a compound, aluminium chloride, containing only aluminium and chlorine. A 0.500 g sample of aluminium chlor
- June 2017, AS Paper 1, Q7(a) (5 marks): Complete the table and determine the concentration, in mol dm–3 , of the hydrochloric acid solution, giving the answer to an appropriate number of significant f
- June 2017, AS Paper 1, Q7(b) (1 mark): The colour change at the end-point when methyl orange is used as an indicator for this titration is from (1) A orange to yellow B red to orange C yellow to oran
- June 2017, AS Paper 1, Q7(c) (3 marks): Explain three actions the technician might take in the procedure, just before the end-point of the titration, to ensure that the volume of acid added at the end
- June 2017, AS Paper 1, Q8(a)(i) (2 marks): Write the equation for the reaction between calcium carbonate and hydrochloric acid. Include state symbols. (2)
- June 2017, AS Paper 1, Q8(a)(ii) (1 mark): Calculate the molar mass of calcium carbonate. (1) g mol–1
- June 2017, AS Paper 1, Q8(a)(iii) (2 marks): Show that, in each experiment, the hydrochloric acid is in excess. (2)
- June 2017, AS Paper 1, Q8(b)(i) (2 marks): Plot a graph of volume of carbon dioxide produced against mass of calcium carbonate on the grid. Include a line of best fit. (2)
- June 2017, AS Paper 1, Q8(b)(ii) (1 mark): State how your graph supports the idea that the volume of gas produced depends directly on the mass of calcium carbonate added. (1)
- June 2017, AS Paper 1, Q8(c) (2 marks): Calculate the volume, under these conditions, of one mole of carbon dioxide gas from these data. Give your answer in dm3 to two significant figures. (2)
- June 2017, AS Paper 1, Q8(d) (1 mark): Give a reason why the student added a small pinch of calcium carbonate to the acid before starting the reaction. (1)
- June 2017, AS Paper 2, Q3(a) (4 marks): In an experiment, 1.000 g of a hydrocarbon, A, was burned completely in oxygen to produce 3.143 g of carbon dioxide and 1.284 g of water. In a different experim
- June 2017, AS Paper 2, Q5(a) (1 mark): State what is meant by the term molar volume of a gas. (1)
- June 2017, AS Paper 2, Q5(b)(i) (2 marks): The gas syringe has a total uncertainty of ±0.5 cm3. Each reading on the balance has an uncertainty of ±0.0005 g. Calculate the percentage uncertainty in the me
- June 2017, AS Paper 2, Q5(b)(ii) (2 marks): The student repeated the experiment with 100 cm3 of the gas using a 100 cm3 syringe. The total uncertainty for this larger syringe was also ±0.5 cm3. Determine
- June 2017, AS Paper 2, Q5(b)(iii) (2 marks): Calculate the molar mass of the gas used in the procedure outlined in part (b). You may assume that one mole of gas occupies 24 000 cm3 under these conditions.
- June 2017, AS Paper 2, Q5(b)(iv) (2 marks): Explain how the student would know if the syringe had a leak in step 2 and what effect this leak would have on the molar mass determined in part (b)(iii). (2)
- June 2017, AS Paper 2, Q5(c) (2 marks): If the temperature had been less than 20 °C and the pressure remained at one atmosphere, deduce the effect, if any, on the molar mass calculated in part (b)(iii
- June 2017, AS Paper 2, Q5(d) (1 mark): Give a reason why the gas should be dry. (1)
- June 2017, AS Paper 2, Q8(c)(i) (2 marks): Calculate the moles of propanedioic acid in 10.0 cm3 of the acid solution. (2)
- June 2017, AS Paper 2, Q8(c)(ii) (2 marks): Calculate the mass of propanedioic acid in the 250 cm3 solution. (2)
- June 2017, AS Paper 2, Q8(c)(iii) (2 marks): Calculate the percentage yield for the oxidation of propane-1,3-diol to propanedioic acid. (2)
- June 2017, AS Paper 2, Q8(c)(iv) (1 mark): Give one reason why the yield calculated in (iii) is less than 100%. (1)
- June 2016, AS Paper 1, Q1(e) (1 mark): What is the number of ions in 9.53 g of magnesium chloride, MgCl2? [Avogadro constant = 6.02 × 1023 mol–1] (1) A 6.02 × 1022 B 1.20 × 1023 C 1.81 × 1023 D 6.02
- June 2016, AS Paper 1, Q3(a)(i) (1 mark): Calculate the number of moles of magnesium used by the student in each experiment. (1)
- June 2016, AS Paper 1, Q3(a)(ii) (1 mark): Use your answer from part (a)(i) to deduce the number of moles of hydrogen gas that should be produced. (1)
- June 2016, AS Paper 1, Q3(a)(iii) (4 marks): Calculate, using the Ideal Gas Equation, the volume of hydrogen gas, in cm3, that should be produced in each of these experiments. [pV = nRT R = 8.31 J mol–1 K–
- June 2016, AS Paper 1, Q3(b) (1 mark): Give a reason why the student repeated the experiment three times. (1)
- June 2016, AS Paper 1, Q3(c) (6 marks): Give three reasons for the difference between your calculated value in (a)(iii) and the actual volumes of hydrogen gas obtained by the student. For each reason,
- June 2016, AS Paper 1, Q5(a) (1 mark): Select the appropriate titres and calculate the mean titre in cm3. (1)
- June 2016, AS Paper 1, Q5(b) (5 marks): Calculate the concentration of the undiluted nitric acid in g dm–3. Give your answer to one decimal place. Deduce whether this nitric acid is suitable for use i
- June 2016, AS Paper 1, Q5(d) (1 mark): One possible method for the formation of nitric acid involves the reaction between dinitrogen tetroxide and water. 3N2O4 + 2H2O r 4HNO3 + 2NO Calculate the atom
- June 2016, AS Paper 1, Q8(b)(i) (2 marks): One compound contains 45.79% sulfur and 54.21% fluorine by mass. Calculate the empirical formula of this compound. (2)
- June 2016, AS Paper 1, Q8(b)(ii) (1 mark): In a dry container, a fluoride of silver reacts with sulfur to produce disulfur difluoride. Complete the equation for this reaction. State symbols are not requi
- June 2016, AS Paper 2, Q4(a) (2 marks): Calculate the number of molecules in 55.2kg of ethanol. [Avogadro Constant = 6.02 × 1023 mol–1] (2)
- June 2016, AS Paper 2, Q5(e) (3 marks): In the preparation, 15cm3 of 2-methylpropan-2-ol produced 6.9 cm3 of 2-chloro-2-methylpropane. The equation for the reaction is (CH3)3COH + HCl o (CH3)3CCl + H2
- June 2016, AS Paper 2, Q7(a) (2 marks): Alcohol X has the following percentage composition by mass: carbon, C = 68.2% hydrogen, H = 13.6% oxygen, O = 18.2% The molecular ion peak in the mass spectrum
- June 2016, AS Paper 2, Q8(b)(i) (4 marks): Describe how the student should prepare the 250.0 cm3 of ethanedioic acid solution. (4)
- June 2016, AS Paper 2, Q8(b)(ii) (1 mark): Give the colour change at the end-point in this titration. (1) From to
- June 2016, AS Paper 2, Q8(b)(iii) (5 marks): Calculate a value of n in the formula H2C2O4.nH2O from these data. (5)
- June 2016, AS Paper 2, Q8(b)(iv) (2 marks): The student thought that the ethanedioic acid crystals used may have been slightly damp. Explain the effect of using damp crystals on the titre and on the value
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