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.

You are asked to investigate the effect of temperature on the rate of decomposition of aqueoushydrogen peroxide.Aqueous hydrogen peroxide decomposes to make oxygen gas.hydrogen peroxide , water + oxygenThe reaction is very slow unless a catalyst is added to the hydrogen peroxide.Manganese(IV) oxide is a catalyst for this reaction.Plan an investigation to find how the temperature of the aqueous hydrogen peroxide afects the rate of the catalysed reaction. Your answer should include an explanation of how your resul's wil tell you how the rate of reaction has changed.You are provided with aqueous hydrogen peroxide, manganese(IV) oxide and common laboratoryapparatus.

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

*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

) 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]

Decomposition of H2O2 follows a first order reaction. In fifty minutes the concentration of H2O2 decreases from 0.5 to 0.125 M in one such decomposition. When the concentration of H2O2 reaches 0.05 M, the rate of formation of O2 will be: