Question

For the first order process:

A → B

The half-life of A is 62.1 seconds.  If a sample of A initially has 250.0 g, what mass (in g) of A will remain after 84.2 seconds?

Answer 1

From the problem

  

t_{​​​​​​1/2} = 62.1 S

From the half life equation (6) , we can write   

K= 0.011159 S^{​​​​​​-1}

Here also given that initial mas(a) = 250.0 g

time (t) = 84.2 Seconds = 84.2 S

Rate constant (K ) = 0.011159 S^-1​​​​

From equation (3a ) we can write that

  

To find the mass of A will remain after 84.2 seconds we have to determine the ( a- x) .

Hence 97.7 g of A will remain after 84.2 Seconds .