Question

Using initial rate, in Chemical Kinetics, what is the missing number in the table? No other information is given. Could you also please explain how you got the answer? I will rate your answer. :D

[A] M	Initial Rate (M/s)
0.100	0.00160
0.200	0.0128
0.300	0.0432
0.400	0.102
0.250	???????

Thanks in advance.

Answer 1

rate = k [A]ⁿ

first we have to find out order (n) . for that substitute rate and concentration of A value

first try n=1 and n=2 . we cannot get same k value.

now : if n=3

data (1) :   rate = k [A]ⁿ

              0.00160 = k [0.1]^3

                k = 1.6

data (2)   : 0.0128 = k [0.2]^3

                   k =1.6

data (3) :    0.0432 = k [0.3]^3

                   k = 1.6

from the above calculation k value is constant (1.6) for n=3 . so it is 3rd order reaction

rate = k [A]ⁿ

        = 1.6 x [0.25]³

        = 0.025

initial rate (missing number) = 0.025 M/s