# Iodine Clock Reaction Help Please!

Submitted by calle on Tue, 02/07/2012 - 04:30

 Exp. Solution1: 0.200M KI Solution2: 2% starch Solution3: 0.020M Na2S2O3 Solution4: water Solution5: 0.050M acetate buffer Solution6: 0.40M H2O2 1 2.00mL 1mL 1.00mL 5mL 10mL 1.00mL 2 4.00mL 1mL 1.00mL 3mL 10mL 1.00mL 3 2.00mL 1mL 1.00mL 4mL 10mL 2.00mL

reaction 1:

2I-(aq)+H2O2(aq)+2H+(aq)--->I2(aq)+2H2O(l)

reaction 2:

I2-(aq)+I-(aq)<--->I3-(aq)

reaction 3:

2S2O32-(aq)+I2(aq)--->2I-(aq)+S4O62-

There were 3 experiments and these are the recorded times:

Ex.1 Trail1=166s
Trial2=149s

Ex. 2 Trail1=48s
Trail2=55s

Ex.3 Trail1=5s
Trail2=8s

Determine the rate of reaction with respect to I-. I was given the equation RateI=-Δ [S2O32-]/time. How would i determine the concentration of S2O32 , its not given. Is it equal to the concentration of KI or Na2S2O3? Do i use the reactions to detemine the rate?

[S2O32-] = [Na2S2O3]

You have 1mL of 0.020M Na2S2O3. Find moles of this by volume in L x  molarity.

Then add up all of the volumes to find the total volume of solution mixture. [Na2S2O3] = number of moles/total volume of solution