Question

Half life period of a radioactive substance is 20 days .After 30 days what percentage of the substance will be left?

This is the questions of class 12 Chemistry - Kinetics
Please answer using the chemistry formula

Experts ....please answer and make sure the spam comments have their points removed...Thanks

Answer 1

Answer:

half life is anything's mass getting half.  its an exponential decay, so you cant apply unitary method. (unitary method can only be applied if the ask is multiple of half life, then the remaining mass would be n times 1/2 of the original mass)

left over amount =  original amount (1/2) pow (R) where R is the ratio of Time/halflife.

here % of left over amount is being asked, so it will be nothing but ratio of (left over amount) : (original amount). which will be simply (1/2) pow R

You can calculate it and multiply by 100 to get the answer in %age form.

(1/2)pow (30/20) = (1/2) pow 1.5 = .3535 equivalent to 35.35%