Question

> Ha

19. You have found a mysterious substance that appears to be radioactive. You take a sample to a nuclear chemist who
measures out 100 g. of the substance. Thirty hours later, the chemist tests the sample and finds that 6.25 grams of the
sample remains radioactive. What is the half-life of the sample?
> Nu
> Nu

Answer 1

7.5 hours

Step-by-step explanation:

half life is the a period of time the sample takes to be half the amount it started the period with

it means we can express it as

original amount / (2^n) = current amount

where n is the number of periods

in the problem if we put 100 / (2^n) = 6.25

we will find that n = 4

we divide 30 over 4 and we get that half life of each period will be equal to 7.5