Question

The initial concentration of A is 0.60 M. After 100 seconds, the concentration is 0.060 M.

​What is the concentration of A after 150 seconds?

Answer 1

The initial concentration of A is 0.60 M.

At T=100 Sec

the concebtration is 0.060M

fraction of sample remained is 1/10

the number of half lifes taken to become 1/10 be n

therefore,

            1/(2^n) =1/10                       here n corresponds to total number of times that of t half

2^n = 10

n ln2 = ln10

n = 3.321

therefore t half = 100/3.321

                      =30.103 sec

at t=150 sec

     n=150/30.103

        =4.982

1/2^n =0.0316227797

the above is the fraction of substance remaining

the concentration of remaining substance is =0.0316227797*initial con

                                                                =0.0316227797*0.6=0.019M