You decomposed hydrogen peroxide in the lab. You and your partner do not agree on what the chemical reaction is. The following are the proposed reactions: Your reaction:H2 O2 → H2 + O2 Your partner’s reaction: 2 H2 O2 → 2 H2 O + O2 The following data was collected: Mass of Beaker36.39 g Mass of Beaker and H2 O2 before Rxn 41.31 g Mass of O2 gas Collected during Rxn 2.32 g Using the data above, prove which reaction is correct. Support your answer with stoichiometry.

*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

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

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

) 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]

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.