Question

1. Calculate the rate of reaction for the solution to turn from colorless to blue-black after each addition.

i. ii.

Prepare Solution 1

in the 250 mL Erlenmeyer flask by adding the following solutions at the

specified concentrations

25.0 mL of 0.2 M potassium iodide (KI)

1.0 mL of starch solution

1.0 mL of 0.4 M sodium thiosulfate (Na2S2O3)

48.0 mL of DI water

1 drop EDTA

Volume Added to Solution 1	Reaction time (s)	Total Volume (L)	Rate (mol/L·s)
25 mL (NH4)2S2O8	182	0.075
1 mL Na2S2O3	73	0.076
1 mL Na2S2O3	185	0.077
1 mL Na2S2O3	114	0.078

2. What is the average rate of the reaction for Solution 1 (include units)?

3. What is the concentration of KI and (NH4)2S2O8 in the reaction flask?

M KI M (NH4)2S2O8