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# Help with working out the initial rate

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1. So i have my set of results which included
the volume of:
KI
Water
Na2S2O3
Starch
K2S2O8
and i have the time(and temperature) in which those reactions turned from clear to dark purple

http://www.slideshare.net/wkkok1957/...ock-experiment
The 2 equations on the document there are the supposed 2 equations i need to work out the initial rate

mixture--------- 1 2 3 4 5
vol. KI----------- 5 4 3 2 1
vol, water-------0 1 2 3 4
vol.Na2S2O3-- 2 2 2 2 2
vol.Starch------- 1 1 1 1 1
vol.K2S2O8----- 2 2 2 2 2
time/s------------23.12 37.00 43.47 1.14.19 2.03.90
2. (Original post by Big white)
So i have my set of results which included
the volume of:
KI
Water
Na2S2O3
Starch
K2S2O8
and i have the time(and temperature) in which those reactions turned from clear to dark purple

http://www.slideshare.net/wkkok1957/...ock-experiment
The 2 equations on the document there are the supposed 2 equations i need to work out the initial rate

mixture--------- 1 2 3 4 5
vol. KI----------- 5 4 3 2 1
vol, water-------0 1 2 3 4
vol.Na2S2O3-- 2 2 2 2 2
vol.Starch------- 1 1 1 1 1
vol.K2S2O8----- 2 2 2 2 2
time/s------------23.12 37.00 43.47 1.14.19 2.03.90
This is an iodine clock reaction. You cannot work out the initial rate, only the average rate.

For each run this is the change in concentration over the time taken for the colour change.
3. (Original post by charco)
This is an iodine clock reaction. You cannot work out the initial rate, only the average rate.

For each run this is the change in concentration over the time taken for the colour change.
Oh i see, how could i work out the conc of the S2O8 and S2O3?? I think they're the ones i need to work out to find the average rate
4. (Original post by Big white)
Oh i see, how could i work out the conc of the S2O8 and S2O3?? I think they're the ones i need to work out to find the average rate
Total moles/volume in litres

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