Initial concentrations in reaction mixtures Run number [I-] [BrO3-] [H+] 1 0.002
ID: 793542 • Letter: I
Question
Initial concentrations in reaction mixtures
Run number [I-] [BrO3-] [H+]
1 0.002 0.008 0.02
2 0.002 0.016 0.02
3 0.004 0.008 0.02
4 0.002 0.008 0.04
When the experiment is repeated at 31 oC, the rate constant is found to be 2.0 times larger.
2-
[S2 O3^ ] is equal to 0.0001M in each reaction mixture.
The rate law is :
a b c
Rate = k [ I-]^ [ BrO3 -]^ [H+]^
Reaction time in run number 1 30
Reaction time in run number 2 30
Reaction time in run number 3 30
Reaction time in run number 4 15
a in the rate law 0
b in the rate law 0
c in the rate law 1
calculate k in the rate law
Explanation / Answer
given that:
rate = k([I-]^a)([BrO3-]^b)([H+]^c]
Also, we have: a = 0, b = 0, c = 1
=> substituting the above values in the rate law gives: rate = k([I-]^0)([BrO3-]^0)([H+]^1]
=> rate = k[H+]
In run number 1: [H+] = 0.02M and run time is 30 => rate = 0.02/30
So,
0.02/30 = k x 0.02
=> k = 1/30 s^-1