Question
Experiment [S2O82- ](
M) [I- ](
M) Initial Rate (
M/s) 1 0.080 0.034 2.2 X 10-4 2 0.080 0.017 1.1 X 10-4 3 0.16 0.017 2.2 X 10-4
Determine the rate law.
____________________ Calculate the rate constant.
______________ /(
M·s) Experiment [S2O82- ](
M) [I- ](
M) Initial Rate (
M/s) 1 0.080 0.034 2.2 X 10-4 2 0.080 0.017 1.1 X 10-4 3 0.16 0.017 2.2 X 10-4 The reaction of peroxydisulfate ion (S2O8^2-) with iodide ion (I -) is given below. The following data are collected at a certain temperature. Determine the rate law. ____________________ Calculate the rate constant. ______________ /(Ms)
Explanation / Answer
By observing the above data keeping the concentration ofS2O82- constant & ondecresing the concencentration of I- to half of theinitial amount , the rate of the reaction is also reduced tohalf So , the rate of the reaction w.r.t I -is rate [I-] 1 keeping the concentration of I - constant & ondoubling the concencentration S2O82- , the rate of the reaction is also doubled. So , the rate of the reaction w.r.t S2O82- is rate [S2O82- ]1 So the over all rate law of the reaction is givenby Rate = k[S2O82- ] 1 [I-] 1 Where k is rate constant Consider the first case Experiment [S2O82- ](
M) [I- ](
M) Initial Rate (
M/s) 1 0.080 0.034 2.2 X 10-4 Substitutethe values in Rate = k [S2O82- ] 1 [I-]1 we have 2.2 * 10^-4 = k * 0.08 * 0.034 k = 8.088 * 10^-2 keeping the concentration of I - constant & ondoubling the concencentration S2O82- , the rate of the reaction is also doubled. So , the rate of the reaction w.r.t S2O82- is rate [S2O82- ]1 So the over all rate law of the reaction is givenby Rate = k[S2O82- ] 1 [I-] 1 Where k is rate constant Where k is rate constant Consider the first case Experiment [S2O82- ](
M) [I- ](
M) Initial Rate (
M/s) 1 0.080 0.034 2.2 X 10-4 Substitutethe values in Rate = k [S2O82- ] 1 [I-]1 we have 2.2 * 10^-4 = k * 0.08 * 0.034 k = 8.088 * 10^-2 Experiment [S2O82- ](
M) [I- ](
M) Initial Rate (
M/s) 1 0.080 0.034 2.2 X 10-4