H2o2 Rates Of Reaction Lab

H2O2 Rates of Reaction Lab Michael Mohamed SCH4U0 October 24th, 2008 Purpose: To produce a detailed and graphical analysis of a reaction involving a gas. Observations: Time elapsed (min)

Gas Volume Produced (mL)

1.0

30

1.5

39

2.0

45

2.5

50

3.0

54

3.5

57

4.0

61

4.5

64

5.0

66

5.5

68

6.0

70

6.5

71

7.0

73

7.5

75

8.0

77

8.5

78

9.0

79

9.5

80

10.0

80

10.5

80

11.0

81

Value Atmospheric Pressure Temperature 1% H2O2(aq)

Measurement 102.7 kPa 295 K 25ml

Discussion: 1) See graph paper for graph of reaction. 2) Balanced chemical equation for the reaction: 2H2O2(aq) --(MnO2(s)) 2H2O(l) + O2(g) 3) The manganese dioxide in this reaction is acting as a catalyst, it is unaffected by the reaction. 4) In this experiment 81mL of O2(g) was produced, the moles produced can be given by pV = nRT where p is pressure, V is volume, n is the amount of moles, R is the Ideal Gas Constant = 8.314(kPa*L)/(mol*K) and T is the temperature in Kelvin. n=pV/Rt n = ((102.7kPa)*(0.081L))/(( 8.314472(kPa*L)/(mol*K)*(295K)) n=0.0035401618132 mol O2 5) To find the coefficient by which to multiply the amount of moles had (in O2(g)) to moles want (in H2O2(aq)), use the coefficients of the balanced equation:

2H2O2(aq) --(MnO2(s)) 2H2O(l) + O2(g) Coefficient = moles want/moles have Coefficient=2H2O2(aq)/1O2(g) Coefficient=2 Then find the moles by multiplying: 2*0.0035401618132 mol O2(g) = 0.0070803236264 mol H2O2(aq) 6) See the graph for tangent slopes and also calculations relating to them. Conclusion: The method used of capturing escaping O2(g) bubbles from a delivery device such as an Erlenmeyer flask with a cork and a plastic tube can hardly be considered accurate, not to mention that in total only 11 minutes were spent reacting, the amount accumulated may have been greater later on if such was allowed. One would have expected .025ml The rates of reaction are not perfectly accurate as they only use the data set from this experiment (which may or may not be very accurate at all) and not a function that could be used to define the decomposition rate of H2O2(aq). Another inaccuracy is the method of calculating tangent slopes being used (estimation of tangent line and then points on the graph of the tangent line to attain slope), it would be better to have a function which could be differentiated into an accurate graph of the rate of reaction.