Rate equations and orders: Edexcel International A Level Chemistry questions

Every Edexcel International A Level Chemistry exam question on Rate equations and orders (specification points 11.1–11.9), 2019–2025, with its mark scheme and examiner’s report.

All 156 questions on Rate equations and orders, as a list

June 2025, Unit 4, Q9 (1 mark): In an experiment to determine the rate of reaction between bromine and methanoic acid, which method would not be suitable? Br2(aq) + HCOOH(aq) → 2H+(aq) + 2Br−(
June 2025, Unit 4, Q10 (1 mark): The reaction shown is second order with respect to NO and first order with respect to O2 . 2NO(g) + O2(g) → 2NO2(g) If the concentration of NO is doubled and th
June 2025, Unit 4, Q11 (1 mark): A chloroalkane, RCl, undergoes hydrolysis according to the equation shown. RCl + OH− → ROH + Cl− The rate equation is rate = k[RCl] Which chloroalkane is most l
June 2025, Unit 4, Q18(a)(i) (1 mark): The reaction in the sample stops immediately on removal from the reaction mixture. Suggest why this occurs. (1)
June 2025, Unit 4, Q18(a)(ii) (1 mark): State why it is not necessary to calculate the concentration of hydrogen peroxide solution when trying to deduce the order of reaction with respect to hydrogen
June 2025, Unit 4, Q18(a)(iii) (3 marks): Plot a graph of the volume of potassium manganate(VII) solution against time. (3)
June 2025, Unit 4, Q18(a)(iv) (3 marks): Use your graph to show that the reaction is first order with respect to hydrogen peroxide. You must show your working on the graph. (3)
June 2025, Unit 4, Q18(b) (2 marks): Two possible mechanisms have been suggested by students carrying out this reaction. Mechanism 1 Step 1 2H2O2(aq) → [H4O4] (aq) slow transition state [H4O4](aq)
January 2025, Unit 4, Q15 (1 mark): A graph of the concentration of Q during decomposition is shown. 10 9 8 7 6 [Q] 5 / 10–3 mol dm–3 4 3 2 1 0 0 30 60 90 120 150 180 210 240 270 300 Time / minute
January 2025, Unit 4, Q18(a) (6 marks): Halogenoalkanes are hydrolysed by aqueous alkali to form alcohols. RX + OH– → ROH + X– The rate equations for these reactions with two halogenoalkanes are shown
January 2025, Unit 4, Q18(b)(i) (2 marks): Give the colour change after all the thiosulfate is used up. (2)
January 2025, Unit 4, Q18(b)(ii) (3 marks): Plot a graph of reaction rate against volume of hydrogen peroxide. (3)
January 2025, Unit 4, Q18(b)(iii) (1 mark): State and justify the reaction order with respect to hydrogen peroxide by using your graph. (1)
January 2025, Unit 4, Q18(c)(i) (2 marks): The graph shows the results of an experiment at 80°C. 80 70 60 50 Volume of hydrogen 40 / cm3 30 20 10 0 10 20 30 40 50 60 70 80 90 Time / s Calculate the react
January 2025, Unit 4, Q18(c)(ii) (2 marks): The temperature of the reaction was changed to 75°C. Draw a line on the graph to show the possible results if this was the only change. Justify any similarities
January 2025, Unit 6, Q4(a)(i) (1 mark): Give the name of the most suitable technique to monitor the concentration of In2– during the reaction. (1)
January 2025, Unit 6, Q4(a)(ii) (3 marks): Plot a graph of the concentration of In2– against time. (3)
January 2025, Unit 6, Q4(a)(iii) (2 marks): Determine two successive half-lives for the concentration of In2–. You must show your working on the graph. (2) First half‑life Second half‑life
January 2025, Unit 6, Q4(a)(iv) (2 marks): Deduce the order with respect to In2–. Justify your answer. (2)
January 2025, Unit 6, Q4(a)(v) (2 marks): Explain why the results of this experiment do not allow the overall order of the reaction to be determined. (2)
October 2024, AS Unit 3, Q4(b)(ii) (3 marks): Calculate the maximum rate of foam production measured for PbO2. Include units with your answer. (3) Units
October 2024, Unit 4, Q18(b) (1 mark): Deduce the rate equation for the reaction using the mechanism in (a)(i). (1)
October 2024, Unit 4, Q18(c) (1 mark): Sketch a line on the axes to show how the concentration of ethanal affects the rate of this reaction. (1) Rate / mol dm–3 s–1 [CH3CHO] / mol dm–3
October 2024, Unit 4, Q19(a)(ii) (3 marks): Show that the data in the table are consistent with the SN2 mechanism for this hydrolysis of 2‑bromobutane. (3)
October 2024, Unit 6, Q2(a)(i) (1 mark): A group of students investigated the kinetics of the reduction of peroxydisulfate ions by iodide ions in aqueous solution, as shown in Reaction 1. 2–(aq) + 2I–(
October 2024, Unit 6, Q2(a)(ii) (1 mark): A group of students investigated the kinetics of the reduction of peroxydisulfate ions by iodide ions in aqueous solution, as shown in Reaction 1. 2–(aq) + 2I–(
October 2024, Unit 6, Q2(a)(iii) (1 mark): A group of students investigated the kinetics of the reduction of peroxydisulfate ions by iodide ions in aqueous solution, as shown in Reaction 1. 2–(aq) + 2I–(
October 2024, Unit 6, Q2(a)(iv) (1 mark): A group of students investigated the kinetics of the reduction of peroxydisulfate ions by iodide ions in aqueous solution, as shown in Reaction 1. 2–(aq) + 2I–(
October 2024, Unit 6, Q2(b)(i) (1 mark): A group of students investigated the kinetics of the reduction of peroxydisulfate ions by iodide ions in aqueous solution, as shown in Reaction 1. 2–(aq) + 2I–(
October 2024, Unit 6, Q2(b)(ii) (2 marks): A group of students investigated the kinetics of the reduction of peroxydisulfate ions by iodide ions in aqueous solution, as shown in Reaction 1. 2–(aq) + 2I–(
October 2024, Unit 6, Q2(b)(iii) (2 marks): A group of students investigated the kinetics of the reduction of peroxydisulfate ions by iodide ions in aqueous solution, as shown in Reaction 1. 2–(aq) + 2I–(
October 2024, Unit 6, Q2(c)(i) (2 marks): A group of students investigated the kinetics of the reduction of peroxydisulfate ions by iodide ions in aqueous solution, as shown in Reaction 1. 2–(aq) + 2I–(
October 2024, Unit 6, Q2(c)(ii) (1 mark): A group of students investigated the kinetics of the reduction of peroxydisulfate ions by iodide ions in aqueous solution, as shown in Reaction 1. 2–(aq) + 2I–(
June 2024, Unit 4, Q1(a) (1 mark): Which continuous monitoring method could be used to obtain kinetics data for this reaction? (1) A colorimetry B mass change C titration with sodium thiosulfate
June 2024, Unit 4, Q1(b) (1 mark): What are the units of the rate constant, k, for this reaction? (1) A mol dm–3 s–1 B dm3 mol–1 s–1 C dm6 mol–2 s–1 D dm9 mol–3 s–1
June 2024, Unit 4, Q1(c) (1 mark): The concentrations of all reactants are halved. By what factor does the rate of reaction change? (1) 1 A 2 1 B 4 1 C 8 1 D 16
June 2024, Unit 4, Q1(d) (1 mark): The first four steps in the reaction mechanism are shown. Step 1 – + H+ → BrO3H BrO3 Step 2 BrO3H + H+ → BrO3H2 + Step 3 + + Br– → Br2O2 + H2O BrO3H2 Step 4 Br2
June 2024, Unit 4, Q9 (1 mark): The rate equation for the hydrolysis of a halogenoalkane, RX, in aqueous alkali is shown. rate = k [RX] Which of these statements is true? A the mechanism invol
June 2024, Unit 4, Q16(a)(i) (3 marks): Calculate the initial rate of reaction, in mol dm–3 s–1, at 1000 K. You must show your working on the graph. (3)
June 2024, Unit 4, Q16(a)(ii) (2 marks): Deduce the rate equation for this reaction at 1000 K, by determining two half‑lives. You must show your working on the graph. (2)
June 2024, Unit 6, Q3(a)(i) (2 marks): Explain why Step 3 effectively stops the reaction between potassium manganate(VII) and ethanedioate ions. (2)
January 2024, Unit 4, Q2 (1 mark): Nitrogen(V) oxide, N2O5, decomposes in a first order reaction. At 45 °C, the half‑life for this reaction is 1400 s. In an experiment, the initial concentration
January 2024, Unit 4, Q16(a)(i) (1 mark): State the final colour of the mixture containing the starch‑iodine complex. (1)
January 2024, Unit 4, Q16(a)(ii) (2 marks): Under appropriate conditions, the reciprocal of time can be used as an approximate measure of the initial rate of the reaction. Explain why the concentration of
January 2024, Unit 4, Q16(b)(i) (3 marks): Use the results in the table to deduce the order of Reaction 1 with respect to hydrogen peroxide, hydrogen ions and iodide ions. Justify each answer by referrin
January 2024, Unit 4, Q16(b)(ii) (1 mark): Write the overall rate equation for Reaction 1 using your answers to (b)(i). (1)
January 2024, Unit 4, Q16(b)(iii) (1 mark): All four mixtures contained 8.50 × 10–5 mol of sodium thiosulfate. Calculate the amount of iodine that had reacted with the sodium thiosulfate when the colour c
January 2024, Unit 4, Q16(b)(iv) (2 marks): Calculate the rate of reaction, in mol dm–3 s–1, with respect to hydrogen peroxide using the answer from (b)(iii), the stoichiometry of Reaction 1 and data from
January 2024, Unit 4, Q16(b)(v) (2 marks): Calculate a value for the rate constant of Reaction 1 using data from Mixture 1 and your answers to (b)(ii) and (b)(iv). Include the units of the rate constant.
October 2023, Unit 4, Q1(a) (1 mark): (CH3)2C (1) A colorimetry B measurement of change in volume C measurement of change in mass D quenching with ice‑cold water followed by titrating with acid
October 2023, Unit 4, Q1(b) (1 mark): HCOOCH3(aq) + NaOH(aq) → HCOONa(aq) + CH3OH(aq) (1) A colorimetry B measurement of change in volume C measurement of change in mass D quenching with ice‑cold wa
October 2023, Unit 4, Q2 (1 mark): The equation for the reaction of bromate(V) ions with bromide ions in acid solution is shown. BrO– 3(aq) + 5Br–(aq) + 6H+ → 3Br2(aq) + 3H2O(l) The rate equation
October 2023, Unit 4, Q3(a) (1 mark): Which graph shows a reaction that is zero order with respect to reactant Q? (1) [Q] A Time B Rate [Q] [Q] C Time D Rate [Q]
October 2023, Unit 4, Q3(b) (1 mark): The equation for a gas phase reaction is shown. A(g) → B(g) + C(g) The reaction is first order. When the initial pressure of A is 2 atm the half‑life of the rea
October 2023, Unit 4, Q15(c)(i) (1 mark): Give the reason why colorimetry can be used to monitor the rate of the reaction. (1)
October 2023, Unit 4, Q15(c)(ii) (2 marks): Use the data from Experiment 1 to find the value of the rate constant, k. Include units in your answer. (2)
October 2023, Unit 4, Q15(c)(iii) (1 mark): State why the reaction is unlikely to proceed in a single step. (1)
October 2023, Unit 4, Q15(c)(iv) (2 marks): A student proposed the mechanism shown for this reaction. 2NO  N2O2 slow N2O2 + O2 → 2NO2 fast Justify whether or not this mechanism is consistent with the ove
June 2023, Unit 4, Q7 (1 mark): The decomposition of hydrogen peroxide is catalysed by iodide ions. I– 2H2O2(aq) 2H2O(l) + O2(g) The mechanism for this reaction is shown. Step 1: H2O2(aq) + I–
June 2023, Unit 4, Q18(a)(i) (1 mark): Draw a best-fit line on the graph. (1)
June 2023, Unit 4, Q18(a)(ii) (1 mark): State how the graph shows that the reaction is not first order with respect to nitrogen monoxide. (1)
June 2023, Unit 4, Q18(a)(iii) (2 marks): Deduce the orders of reaction with respect to NO and O2 , using the data from experiments 1–6. (2) Order with respect to NO = Order with respect to O2 =
June 2023, Unit 4, Q18(a)(iv) (1 mark): Write the rate equation for the reaction, using your answer to (a)(iii). (1)
June 2023, Unit 4, Q18(a)(v) (2 marks): Calculate the rate constant for this reaction using the data from experiment 1 and your rate equation. Include units in your answer. (2)
June 2023, Unit 5, Q25(f) (3 marks): Articaine is metabolised in the body with a half-life of 20 minutes. A patient is given a dose of 100 mg of articaine. Calculate the mass of articaine in microg
June 2023, Unit 6, Q3(a) (1 mark): State why the sulfuric acid and propanone concentrations are both much larger than the iodine concentration. (1)
June 2023, Unit 6, Q3(b) (1 mark): State why sodium hydrogencarbonate is used in Step 3. (1)
June 2023, Unit 6, Q3(c) (2 marks): Name the indicator that would be used for the titration in Step 4, stating the colour change that would be seen at the end‑point of the reaction. (2)
June 2023, Unit 6, Q3(d)(i) (3 marks): Plot a graph of titre against time. (3)
June 2023, Unit 6, Q3(d)(ii) (1 mark): State why the volume of thiosulfate may be used for plotting the graph rather than the concentration of iodine. (1)
June 2023, Unit 6, Q3(d)(iii) (1 mark): State the order of reaction with respect to iodine. Justify your answer by referring to your graph. (1)
June 2023, Unit 6, Q3(e)(i) (2 marks): A graph of the concentration of propanone against time is shown. 0.20 0.15 Concentration of propanone / mol dm–3 0.10 0.05 0 0 5 10 15 20 25 30 Time / s The rea
June 2023, Unit 6, Q3(e)(ii) (1 mark): A graph of the reaction rate against the concentration of sulfuric acid is shown. Rate Concentration of acid Deduce the rate equation for the overall reaction o
January 2023, Unit 4, Q1(a) (1 mark): Which pair of rate equations could be correct for this reaction? (1) Equation 1 Equation 2 rate = k[NO]2[O2] rate = k[NO]2[O2] A rate = k[NO]2[O2] rate = k[NO][
January 2023, Unit 4, Q1(b) (1 mark): Which two methods can be used for continuous monitoring of the progress of this reaction? (1) A colorimetry and titration B colorimetry and volume change C mass
January 2023, Unit 4, Q2 (1 mark): The half‑life of a first order chemical reaction is A half the time taken for the reaction to be complete B the time taken for the value of the rate constant to
January 2023, Unit 4, Q3 (1 mark): Two chemicals, E and F, react to form products G and H. E + 2F → G + H The mechanism for the reaction occurs in two steps via the formation of an intermediate J
January 2023, Unit 4, Q17(a)(i) (3 marks): The rate of this reaction may be obtained by adding a fixed volume of sodium thiosulfate solution and a few drops of starch solution to the reaction mixture. Ex
January 2023, Unit 4, Q17(a)(ii) (3 marks): The student’s results are shown. [I–(aq)] / mol dm–3 [H2O2(aq)] / mol dm–3 [H+(aq)] / mol dm–3 Rate / mol dm–3 s–1 Run 1 0.0210 0.0198 0.00105 0.00181 2 0.0105
January 2023, Unit 4, Q17(a)(iii) (3 marks): Calculate the rate constant for this reaction at 293 K, using the results from Run 1. Include units with your answer. (3)
January 2023, Unit 6, Q2(a)(i) (1 mark): Give the expected colour change at the end‑point. (1)
January 2023, Unit 6, Q2(a)(ii) (2 marks): Explain the effect on the volume of hydrochloric acid required if the titration was not carried out immediately after Step 4. (2)
January 2023, Unit 6, Q2(b)(i) (2 marks): An experiment was carried out using this procedure. The results are shown. Time / s 50 320 750 1200 2050 3180 4020 Volume of HCl / cm3 24.5 22.0 18.5 15.5 11.0
January 2023, Unit 6, Q2(b)(ii) (2 marks): Determine two successive half‑lives for the reaction. You must show your working on the graph. (2)
January 2023, Unit 6, Q2(b)(iii) (1 mark): State the order of this reaction. Justify your answer. (1)
October 2022, Unit 4, Q1 (1 mark): Which continuous monitoring method could be used to obtain rate data for the reaction shown? C4H9Cl(l) + H2O(l) → C4H9OH(aq) + H+(aq) + Cl−(aq) A electrical con
October 2022, Unit 4, Q2(a) (1 mark): The concentrations of both reactants are tripled. By what factor does the rate of reaction increase? (1) A 3 B 9 C 18 D 27
October 2022, Unit 4, Q2(b) (1 mark): Which graph is correct for this reaction? (1) A B [H2] Rate Time [H2] C D [NO] Rate [NO]2 Time
October 2022, Unit 4, Q2(c) (1 mark): The reaction mechanism occurs in three steps. Step 1 NO + NO  N2O2 Step 2 N2O2 + H2 → N2O + H2O Step 3 N2O + H2 → N2 + H2O Which is the rate-determining step i
October 2022, Unit 4, Q16(a) (1 mark): Write the rate equation for this first order reaction. (1)
October 2022, Unit 4, Q16(b)(i) (2 marks): Determine values for the half-life, t1/2 , of the decomposition of azomethane from the graph, stating whether or not these data confirm that the reaction is fir
October 2022, Unit 4, Q16(b)(ii) (2 marks): Calculate the rate constant, k, in s−1 , for the decomposition of azomethane at 573 K , using your answer to (b)(i) and the expression shown. = l n2 t 1/2 k (2)
October 2022, Unit 6, Q4(b)(i) (1 mark): Give a reason why Vfinal – Vt is plotted on the y‑axis of the graph, rather than the concentration of sodium hydroxide solution for each titre. (1)
October 2022, Unit 6, Q4(b)(ii) (2 marks): Explain how the data collected indicates first order kinetics. Show your working on the graph. (2)
October 2022, Unit 6, Q4(b)(iii) (2 marks): The student concluded that the reaction is first order overall. Explain whether or not this statement is valid. (2)
October 2022, Unit 6, Q4(b)(iv) (4 marks): Calculate the rate of the reaction at a time of 2 hours. Include units with your answer. Show your working on the graph. (4)
October 2022, Unit 6, Q4(c) (2 marks): The student suggested placing ice in the conical flask before carrying out each titration. Explain whether or not this suggestion would improve the validity of
June 2022, Unit 4, Q10(a) (1 mark): Which graph shows the rate of reaction on the vertical axis plotted against concentration of the reactant on the horizontal axis for a zero order reaction? (1)
June 2022, Unit 4, Q10(b) (1 mark): Which graph shows the rate of reaction on the vertical axis plotted against concentration of the reactant on the horizontal axis for a first order reaction? (1)
June 2022, Unit 4, Q11(a) (1 mark): Which method would be most suitable for following this reaction? (1) A colorimetry B timing how long the solution takes to go cloudy C quenching and titrating w
June 2022, Unit 4, Q11(b) (1 mark): The rate equation for this reaction is: rate = k[H+][CH3COCH3] Two experiments were carried out. In both experiments the concentration of propanone and iodine r
June 2022, Unit 4, Q20(a)(i) (2 marks): Deduce the order of reaction with respect to 2‑bromobutane and with respect to hydroxide ions. Justify your answers. (2)
June 2022, Unit 4, Q20(a)(ii) (1 mark): Write the rate equation for the reaction using your answer to (a)(i). (1)
June 2022, Unit 4, Q20(a)(iii) (2 marks): Calculate the rate constant for Experiment 1. Include units in your answer. (2)
January 2022, Unit 4, Q12(b) (1 mark): The rate equation for the reaction between propanone and iodine in acidic conditions is rate = k[H+][CH3COCH3] The reaction was carried out at two different pH
January 2022, Unit 4, Q18(a)(i) (4 marks): Deduce the rate equation for the reaction. Justify your answer using the data. (4)
January 2022, Unit 4, Q18(a)(ii) (3 marks): Use the data from Experiment 4 and your answer to (a)(i) to calculate the rate constant for the reaction. Include units in your answer. (3)
January 2022, Unit 4, Q18(b) (1 mark): Give one possible reason why the rate equation shows that the reaction cannot proceed in one step. (1)
January 2022, Unit 4, Q19(a)(iii) (2 marks): KCN is a homogeneous catalyst in this reaction. Justify this description by referring to the mechanism. (2)
January 2022, Unit 6, Q3(a) (1 mark): Give one reason why the contents of beaker P are poured back into beaker Q in Step 3. (1)
January 2022, Unit 6, Q3(b)(i) (2 marks): Explain why phenol is added to the reaction mixture. (2)
January 2022, Unit 6, Q3(b)(ii) (1 mark): Give the colour of the reaction mixture before it turns colourless. (1)
January 2022, Unit 6, Q3(b)(iii) (1 mark): Give the reason why the temperature is measured in Step 4. (1)
January 2022, Unit 6, Q3(c)(i) (1 mark): Complete the table by calculating the remaining values of 1/t. (1)
January 2022, Unit 6, Q3(c)(ii) (3 marks): Plot a graph of 1/t against the volume of KBr. Include a line of best fit. (3) 0 0
January 2022, Unit 6, Q3(c)(iii) (1 mark): State why the volume of KBr is proportional to the concentration of bromide ions in the reaction mixture. (1)
January 2022, Unit 6, Q3(c)(iv) (1 mark): State the order of reaction with respect to bromide ions, using your graph. (1)
January 2022, Unit 6, Q3(d) (1 mark): After investigating the effect on the rate of the concentration of bromate(V) ions and the concentration of hydrogen ions, the student obtained the graphs shown
October 2021, Unit 4, Q1(a) (1 mark): What is the rate equation for this reaction? (1) A rate = k B rate = k[NH3] C rate = k[NH3]2 D rate = k[N2][H2]3
October 2021, Unit 4, Q1(b) (1 mark): What are the units of the rate constant, k, for this zero order reaction? (1) A no units B s−1 C mol dm−3 s−1 D dm3 mol−1 s−1
October 2021, Unit 4, Q1(c) (1 mark): Which of these graphs represents this zero order reaction? (1) Rate Rate [NH3] [NH3] A B [NH3] [NH3] Time Time C D
October 2021, Unit 4, Q17(a)(i) (3 marks): Plot a graph of concentration of benzenediazonium chloride against time. (3)
October 2021, Unit 4, Q17(a)(ii) (1 mark): Determine a value for the half-life, t½ , of this reaction. You must show your working on the graph. (1)
October 2021, Unit 4, Q17(a)(iii) (2 marks): Calculate the rate constant, k, for the reaction at 333 K. Include units in your answer. Use the expression ln 2 = kt½ (2)
October 2021, Unit 4, Q18 (6 marks): *18 The hydrolysis of halogenoalkanes by alkali is a nucleophilic substitution reaction. RX + OH− → ROH + X− The mechanism of this reaction for primary halogeno
June 2021, Unit 4, Q6 (1 mark): Nitrogen monoxide and hydrogen react together to form nitrogen and water. 2NO + 2H2 → N2 + 2H2O The steps in the mechanism of the reaction are 2NO ⇌ N2O2 Step 1
June 2021, Unit 4, Q16(a)(i) (3 marks): Use the results to plot a suitable graph that can be used to show that the reaction is first order with respect to bromate(V) ions. (3)
June 2021, Unit 4, Q16(a)(ii) (1 mark): State how your graph shows that the reaction is first order with respect to bromate(V) ions. (1)
June 2021, Unit 4, Q16(b)(i) (2 marks): Use these results and your answer to (a) to deduce the orders with respect to Br– ions and H+ ions. (2) Br– ions H+ ions
June 2021, Unit 4, Q16(b)(ii) (1 mark): Write the rate equation for the reaction. (1)
June 2021, Unit 4, Q16(b)(iii) (3 marks): Use the results for Run 1 and your rate equation from (b)(ii) to calculate the value for the rate constant, k. Include units in your answer. (3)
January 2021, Unit 4, Q7 (1 mark): Propanone reacts with iodine in the presence of a catalyst of dilute hydrochloric acid. The reaction occurs in aqueous solution. CH3COCH3 + I2 → CH3COCH2I + HI
January 2021, Unit 4, Q8 (1 mark): The rate equation for a reaction is rate = k[A]2[B]0 The initial rate of reaction is 9.0 × 10−5 mol dm−3 s−1 when [A] = 0.30 mol dm−3 and [B] = 0.20 mol dm−3. W
January 2021, Unit 4, Q20(b)(i) (3 marks): Experiment 1 The concentration of Br− ions is determined at different times. − ions and H+ ions are in large excess and The concentrations of BrO3 effectively c
January 2021, Unit 4, Q20(b)(ii) (3 marks): Experiment 2 − ions and H+ ions are changed and the initial The initial concentrations of BrO3 rate of reaction is determined. The initial concentration of Br−
January 2021, Unit 4, Q20(b)(iii) (2 marks): Give the overall rate equation for this reaction. Include the units for the rate constant. (2)
January 2021, Unit 5, Q24(b)(ii) (2 marks): The removal of caffeine from the body is a first order reaction with a half-life of between three and seven hours for an adult. An adult drinks coffee containin
October 2020, Unit 4, Q1 (1 mark): Bromine oxidises methanoic acid to carbon dioxide. The equation for the reaction is HCOOH(aq) + Br2(aq) → 2H+(aq) + 2Br −(aq) + CO2(g) Which of the following me
October 2020, Unit 4, Q2 (1 mark): The rate of the reaction between two compounds, Y and Z, was investigated. The results are shown. Initial concentration of Y Initial concentration of Z Initial
October 2020, Unit 4, Q3 (1 mark): The inorganic anti-cancer drug cis-platin, Pt(NH3)2Cl2, is hydrolysed by water to make it active. The reaction is + H3N NH3 H3N NH3 + Cl− Pt + H2O Pt Cl Cl Cl H
October 2020, Unit 4, Q4(a) (1 mark): Which of the following is true? (1) A the units for the rate constant are dm3 mol−1 s−1 B the reaction is a first order reaction overall C the units for the rat
October 2020, Unit 4, Q4(b) (1 mark): Which of the following is not true? (1) A the reaction rate increases if the temperature is raised B the rate constant increases if the temperature is raised C
October 2020, Unit 4, Q5 (1 mark): The equation shows the hydrolysis of a bromoalkane. RBr + OH− → ROH + Br− The rate equation is rate = k[RBr] RBr is most likely to be A bromomethane B 2-bromopr
October 2020, Unit 6, Q3(b) (2 marks): Explain the purpose of the phenol in this experiment. (2)
October 2020, Unit 6, Q3(c) (1 mark): Suggest a way of making the disappearance of the methyl red colour easier to see. (1)
October 2020, Unit 6, Q3(d)(i) (1 mark): State why the total volume of the mixture is kept constant. (1)
October 2020, Unit 6, Q3(d)(ii) (3 marks): Plot a graph of reciprocal time (1/t) against volume of bromate(V) solution. (3)
October 2020, Unit 6, Q3(d)(iii) (1 mark): State the order of reaction with respect to bromate(V) ions. Justify your answer. (1)
October 2020, Unit 6, Q3(d)(iv) (1 mark): Reciprocal time (1/t) is used as a measure of rate in this experiment. Suggest the assumption on which this depends. Refer in your answer to the shape of a typi
October 2020, Unit 6, Q3(d)(v) (2 marks): Another student accidentally measured 8.5 cm3 of potassium bromate(V) rather than 8.0 cm3 in Run 4. Explain whether or not this portion of potassium bromate(V)
October 2020, Unit 6, Q3(e)(i) (1 mark): Give a reason why the potassium bromate(V) solution is first measured into a separate boiling tube rather than directly into the reaction mixture. (1)
October 2020, Unit 6, Q3(f) (2 marks): State the changes that you would make to the procedure to obtain the data needed to determine the overall rate equation for the reaction between bromide and bro
January 2020, Unit 4, Q14 (1 mark): A reactant Q is converted into two products. Which of these graphs shows that this reaction is first order with respect to Q? Graph 1 Graph 2 [Q] Rate time [Q]
January 2020, Unit 4, Q15(a) (1 mark): Which statement is not correct? (1) A the reaction is third order overall B the units of the rate of the reaction are mol dm−3 s−1 C the rate of the reaction in
January 2020, Unit 4, Q15(b) (1 mark): What are the units of the rate constant, k, for this reaction? (1) A dm9 mol−3 s−1 B mol3 dm−9 s−1 C mol2 dm−6 s−1 D dm6 mol−2 s−1
January 2020, Unit 4, Q15(c) (1 mark): An experiment was carried out using 1.10 × 10−2 mol dm−3 of oxygen and some nitrogen monoxide. The numerical value of the initial rate and rate constant were: •

Questions, mark schemes and examiner’s reports are © Pearson Edexcel, from their published past papers. Plumi isn’t affiliated with any exam board. Want whole papers? Every Edexcel International A Level Chemistry paper.

Rather write your answers by hand on iPad? Plumi marks them against the same mark schemes.

4,117 questions