IGCSE/GCSE/O & A Level/IB/University Student Forum
Qualification => Subject Doubts => GCE AS & A2 Level => Sciences => Topic started by: guowie88 on November 08, 2010, 03:43:33 pm
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i don't understand the part b]
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i don't understand the part b]
2.(b) Given rate= k[H2O2]a[I-]b[H+]c
a represents the order of reaction with respect to [H2O2].
b represents the order of reaction with respect to [I-].
c represents the order of reaction with respect to [H+].
NOTE : 1. The slowest step is the rate determining step.
2. The number of moles of a reactant in the rate determining step gives the order with respect to that of the reactant.
When step 1 is slowest overall : a=1, b=1 and c=0
This is because in step 1, the number of moles of H2O2 is 1 and so is I-. However H+ is not present in this equation which means it has order zero.(Reaction is independent of H+)
When step 2 is slowest overall: a=1, b=1 and c=1
IO- is formed from H2O2 and I-. Replace the first equation in the second and you'll get :
H2O2 + I- + H+ ---> HOI + H2O
From this equation, note the number of moles of the respective reactants.
When step 3 is slowest overall : a=1, b=2 and c=2.
Replace the new equation found above in this third step and you'll get :
H2O2 + 2I- + 2H+ ---> I2 + 2H2O
From this equation, note the number of moles of the respective reactants.
I sincerely hope my explanations are clear enough for you to understand. :)
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Thk totally understand now ^^
juz like math subsitution XD
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Thk totally understand now ^^
juz like math subsitution XD
Yupz......same to same. ;)
Glad that you understood :)