kinetics - ,andin t

Results and Discussion:
The purpose of this experiment was to determine the dependence of concentration and
temperature for the reaction between peroxydisulfate and iodide ion in aqueous solution.
In order to determine the effects of concentration of the reactants on the reaction, and in
turn determine the rate law equation for this particular reaction, it was necessary to run
various trials in which the concentrations of the reactants varied. Three trials were run
with the following concentrations:
Experiment [I] [S
2
O
8
]
1 .16 .12
2 .08 .12
3 .16 .06
In order to obtain these concentrations, the following table indicates the amounts of each
chemical used for each experiment:
Exp Starch EDTA KI (mL) Na
2
S
2
O
3
(mL)
NH
4
S
2
O
8
(mL)
H
2
O
(mL)
Total volume
(mL)
1 .2 g 1 drop 20 5 5 15 45
2 .2 g 1 drop 10 5 5 25 45
3 .2 g 1 drop 20 5 2.5 17.5 45
By comparing two reactions, with one concentration held constant and the other either
doubling or halving, the rate order for that particular reactant was determined. Three
trials of each experiment were run so that precision could be determined. The following
table shows the reaction time for each trial ran.
Experiment Trial 1 Trial 2 Trial 3
1 140 sec 138 sec 122 sec
2 288 sec 279 sec 300 sec
3 260 sec 269 sec 269 sec
In calculating precision we find that the mean of the values for experiment 1 is 133.33