Question

Run Run [I-1 (Note that 1.4e-5 is the same as 1.4 X105) [S202 ) Class Average Class Average Times (sec) Rate, M sec 0.040 43.2 1.4e-5 = 14 e-6 Class Average Rate Constant 0.080 0.040 85.9 0.040 DOUBLES 0.020 DOUBLES 0.010 0.040 173 7.0 e-6 DOUBLES 1 3.5 e-6 DOUBLES 1.7 e-6 0.040 347 0.040 0.080 44.3 1.4 e-5 = 14 e-6 7.0 e-6 0.040 0.040 86.2 0.040 0.020 T 175 3.4 e-6 1.7 e-6 0.040 0.010 345 ***As the concentration [14] Doubles, the RATE Doubles Then the reaction is FIRST ORDER in [-]

Answer 1

Rate=Rate constantx[I^-]^xx[S₂O₈^2-]^y   

when [I^-] doubles rate also doubled.

$\therefore$ Order with respect to [I^-] is 1

$\therefore$ x=1

by substituting data from run 5&6,we get

14x10^-6/7x10^-6=K [I^-] x [S₂O₈^2-]^y

14x10^-6/7x10^-6=K x0.04x [0.08^-]^y /Kx0.04x [0.04^-]^y

$\therefore$ 2=2^y$\therefore$ y=1 so,Order with respect to S₂O₈^2-is 1

Hence rate equation is  Rate=K [I^-1] [S₂O₈^2-]

Class average rate constant for run 1 is K=rate/[I^-1] [S₂O₈^2-]

K= 14x10^-6/0.08x0.04

=14x10^-6/8x10^-2x4x10^-2

=14x10^-2/32

=0.437x10^-2 =4.37x10^-3

RUN	CLASS AVERAGE RATE
1	4.37x10-3
2	4.37x10-3
3	4.37x10-3
4	4.37x10-3
5	4.37x10-3
6	4.37x10-3
7	4.37x10-3
8	4.37x10-3