) CalculatetheconcentrationofH2 O2 in FA 3, in mol dm –3 . concentrationofH2 O2 in FA 3 = .............................. mol dm–3 [1](v) When hydrogen peroxide decomposes in the presence of a catalyst, oxygen is produced.H2 O2(aq) H2O(l)+12 O2(g) The ‘volume strength’ of hydrogen peroxide is equal to the volume of oxygen, in dm3 ,produced under room conditions, when 1.00 dm 3 of the solution decomposes.Use your answer to (c)(iv) and the equation above to calculate the volume, in dm3 , ofoxygen produced when 1.00 dm3 of FA 3 decomposes. This is the ‘volume strength’, in vol,of FA 3. (Underroomconditions1.00molofgasoccupiesavolumeof24.0dm3 . If you were unable to calculate the concentration of H2 O2 in FA 3, assume that it is1.02 mol dm –3 . This may not be the correct value.)‘volume strength’ of FA 3 = .............................. vol [2](d) Themaximumerrorinreadinga25.0cm3pipetteis±0.06cm3 . Showbycalculationthatthepipetteismoreaccuratethanaburetteformeasuring25.0cm3 ofsolution................................................................................................................................................................................................................................................................................................... [1] [Total:15]

The equation for the decomposition of hydrogen peroxide is shown.2H_{2}*O_{2}(aq) -> 2H_{2}*O(l) + O_{2}(g) 25.0 cm³ of aqueous hydrogen peroxide forms 48.0 cm³ of oxygen at room temperature and pressure (r.t.p.).Calculate the concentration of aqueous hydrogen peroxide at the start of the experiment using the following steps.Calculate the number of moles of oxygen formed.molDeduce the number of moles of hydrogen peroxide that decomposed.molCalculate the concentration of hydrogen peroxide in mol / d * m ^ 3mol / d * m ^ 3[3]Calculate the volume of O, gas, at room temperature and pressure ( r .t.p.) needed to produce 1260 g of HNO3. Use the following steps.4.The equation for the reaction in stage 3 is shown.4N*O_{2} + 2H_{2}*O + O_{2} -> 4HNO

The concentrations of solutions of hydrogen peroxide are often represented in terms of ‘volumestrength’. In this experiment you will determine the ‘volume strength’ of a solution of hydrogen peroxidebytitrationwithacidifiedpotassiummanganate(VII).2MnO 4–(aq)+5H2 O2(aq)+6H+(aq) 2Mn2+ (aq)+8H2O(l)+5O2(g)FA 1 is 0.0300 mol dm –3potassiummanganate(VII), KMnO4 .FA 2isdilutesulfuricacid,H2 SO4 .FA 3isaqueoushydrogenperoxide,H2 O2 .(a) MethodDilution of FA 3● Pipette25.0cm3 of FA 3intothe250cm3 volumetric flask.● Make the solution up to the mark using distilled water.● Shake the flask thoroughly.● Label this diluted solution of hydrogen peroxide FA 4.Titration● Fill the burette with FA 1.● Rinse the pipette thoroughly with distilled water and then with a little FA 4.● Pipette25.0cm3 of FA 4 into a conical flask.● Usethe25cm3 measuring cylinder to add 20 cm3 of FA 2 into the same conical flask.● Perform a rough titration and record your burette readings in the space below.The rough titre is .............................. cm3 .● Carry out as many accurate titrations as you think necessary to obtain consistent results.● Make sure any recorded results show the precision of your practical work.● Record all of your burette readings and the volume of FA 1 added in each accurate titration.Keep FA 1, FA 2 and FA 3 for use in Questions 2 and 3.[7]IIIIIIIVVVIVII39701/33/F/M/20©UCLES 2020 [Turn over(b) From your accurate titration results, obtain a suitable value for the volume of FA 1 to be usedin your calculations.Show clearly how you obtained this value. 25.0cm3 of FA 4required..............................cm3 of FA 1. [1](c) Calculations(i) Give your answers to (ii), (iii), (iv) and (v)totheappropriatenumberofsignificantfigures.[1](ii) Calculate the number of moles of potassium manganate(VII) present in the volumecalculated in (b).moles of KMnO 4 = .............................. mol [1](iii) The equation for the reaction of potassium manganate(VII) with hydrogen peroxide isshown.2MnO 4–(aq)+5H2 O2(aq)+6H+(aq) 2Mn2+ (aq)+8H2O(l)+5O2(g)Use your answer to (c)(ii) to calculate the number of moles of hydrogen peroxide used ineach titration. molesofH2 O2 = .............................. mol HencecalculatetheconcentrationofH2 O2 in FA 4, in mol dm –3 . concentrationofH2 O2 in FA 4 = .............................. mol dm–3

A student investigated the rate of decomposition of hydrogen peroxide using three different catalysts: • manganese dioxide • copper oxide • zinc oxide. Figure 2 shows the apparatus. Figure 2 This is the method used. 1. Measure 20 cm 3of hydrogen peroxide solution into a flask. 2. Add 0.5 g of manganese dioxide catalyst to the flask. 3. Attach a gas syringe to the flask. 4. Measure the volume of oxygen produced every 30 seconds for 180 seconds. 5. Repeat steps 1 to 4 two more times. 6. Repeat steps 1 to 5 using copper oxide catalyst. 7. Repeat steps 1 to 5 using zinc oxide catalyst. it speeds the reaction19 *19* Turn over ► IB/M/Jun23/8464/C/2H Do not write outside the box 0 6 . 1 The equation for the decomposition of hydrogen peroxide is: 2 H2O2 → 2 H2O + O2 Describe a test to identify the gas produced in the reaction. [2 marks] Test Result 0 6 . 2 Using 10 cm 3of hydrogen peroxide solution gives less accurate results than using 20 cm 3of hydrogen peroxide solution of the same concentration. Explain why. [2 marks] 0 6 . 3 Suggest one possible source of systematic error in the investigation. [1 mark] Question 6 continues on the next page relighting a slint. Place a glowing splint into a test tube containing the gas. if the splint relights oxygen is presentbecause 10cm^3 of the peroxide solution would be a limiting factor as it does not fullyreact with the catalyst20cm^3 is less dilute than 10cm^3 so there is more consitant results as if you measure 9cm^3 instead of 10cm^3 you have reduced the volume by 10% whereas if you measure 19cm^3 instead of20cm^3 you have only reduced the bolume by 5%? so it leads to more accurate resultsmeasuring the catalyst on a balance scale with a zero error20 *20* IB/M/Jun23/8464/C/2H Do not write outside the box Table 3 shows the results for manganese dioxide catalyst. Table 3 Time in seconds 0 30 60 90 120 150 180 Volume of gas in cm 30 22 38 41 54 58 60 Figure 3 shows a graph of the results with copper oxide catalyst and with zinc oxide catalyst. Figure 3 0 6 . 4 Complete Figure 3. You should: • plot the data from Table 3 • draw a line of best fit. The first point has been plotted for you. [3 marks] it says line of best fit so does that mean it wouldnt be a curve (like the blue line?)21 *21* Turn over ► IB/M/Jun23/8464/C/2H Do not write outside the box 0 6 . 5 Which catalyst gives the fastest rate of reaction? Give one reason for your answer. Use the completed Figure 3. [2 marks] Catalyst Reason 0 6 . 6 The rate of reaction is not dependent on the volume of hydrogen peroxide solution. Explain why.

*19* Turn over ► IB/M/Jun23/8464/C/2H Do not write outside the box 0 6 . 1 The equation for the decomposition of hydrogen peroxide is: 2 H2O2 → 2 H2O + O2 Describe a test to identify the gas produced in the reaction. [2 marks] Test Result

Hydrogen peroxide decomposes in a first order reaction according to:2 H 2 O 2 (aq) ® H 2 O (l) + O 2 (g)The half-life for the decomposition process is t 1/2 = 360 minutes at 38.0 ℃i. (2 marks)Calculate the value for the rate constant, k 1 for the forward reaction at 38.0 ℃ii. (2 marks)If after 1080 mins, the concentration of H 2 O 2 in a sample is measured to be0.154 mol L-1 , calculate the initial concentration of the H 2 O 2 in this sample.iii. (1 mark)Assuming the decomposition follows Arrhenius behaviour, calculate the Arrheniusconstant for this decomposition process if the activation energy is 42 kJ mol -1 .k1