8. 2 nd Max/Minimum Method Preparing 0.053M from 0.1M KI using pipette. Pipette uncertainty = ± 0.4 Max Conc KI = Max Vol KI and Min Vol of water used M x V (dil) = M x V (conc) M x (15.8 + 14.2) = 0.1 x (15.8) M = 0.1 x ( 15.8 ) / ( 15.8+ 14.2 ) M = 0.053 Max Conc KI = Max Vol KI + Min Vol water Max Vol KI = 15.8 ± 0.4 = 16.2 Min Vol water = 14.2 ± 0.4 = 13.8
9. M x V (dil) = M x V (conc) Max Conc KI = (0.1 x 16.2) / ( 16.2 + 13.8 ) Max Conc = 0.054 Min Conc = Min Vol KI and Max Vol water used Min Vol KI = 15.8 ± 0.4 = 15.4 Max Vol water = 14.2 ± 0.4 = 14.6 M x V (dil) = M x V (conc) M x (15.4 + 14.6) = 0.1 x (15.4) M = 0.1 x ( 15.4 ) / ( 15.4 + 14.6 ) M = 0.051 Min Conc = 0.051 Uncertainty Conc = 0.053 ± ( 0.054 --- 0.051)
10. Uncertainty Calculation, 2 fold Serial dilution using 3% H 2 O 2 Two Methods used 1 st % Uncertainty Method For 1.5% : Total % Uncertainty is 1.6%, Answer = 1.5 ± 1.6% Propagation of error involved
12. 2 nd Max/ Min Method For 2 fold Serial dilution on 3% H 2 O 2 M x V (dil) = M x V (conc) M x (1.5 +1.5) = 3% x 1.5 M = 1.5%
13. Max Conc H 2 O 2 when Min Conc H 2 O 2 when Max Vol H 2 O 2 used = 1.51 Min Vol H 2 O 2 used = 1.49 Min Vol water used = 1.49 Max Vol water used = 1.51 Max Conc H 2 O 2 Min Conc H 2 O 2 M x V (dil) = M x V (conc) M x V (dil) = M x V (conc) M x (1.51 + 1.49) = 3% x ( 1.51 ) M x (1.51 + 1.49) = 3% x ( 1.49 ) M = 3% x ( 1.51 )/ ( 1.51 + 1.49 ) M = 3% x ( 1.49 )/ ( 1.51 + 1.49 ) M = 1.51% M = 1.49% Max Conc = 1.51% Min Conc = 1.49% Uncertainty Conc H 2 O 2 = 1.50 ± (1.51%---1.49%)
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15. Average Rate by taking average for 3 trials Uncertainty for Rate = Standard deviation Use Excel to calculate Std deviation Average rate = (0.113 ±0.015)kPa/s
16. Click HERE to view video on how to insert error bar or standard deviation in Excel
17. Acknowledgements Thanks to source of pictures and video used in this presentation Thanks to Creative Commons for excellent contribution on licenses http://creativecommons.org/licenses/ Prepared by Lawrence Kok Check out more video tutorials from my site and hope you enjoy this tutorial http://lawrencekok.blogspot.com