Question

PLEASE HELP!!

A 100 gram sample is left undisturbed for 8 hours. At the end of that period, only 12.5 grams remain. What is the half-life of this sample?

Answer 1

8/3 hours

Step-by-step explanation:

12.5/100=1/8, 1/8*2=2/8=1/4 1/4*2=1/2 1/2*2 = 1 (whole)

we multiplyed 1/8 by two three times to get 1 so 8/3 hours is the answer

by the way i'm in 6th grade

Answer 2

The half-life of a radioactive substance describes the amount of time required for half of that radioactive substance to decay into a different form.

In this situation, 100 grams decays into 12.5 grams over the course of 8 hours. We have half lives that look like this -

100 grams - 50 grams (1) - 25 grams (2) - 12.5 grams (3)

three half lives have passed since the start over the course of eight hours, so:

8 hours/3 half-lives = ~2.667 hours per half-life

The half-life of this substance is approximately 2.667 hours.

Hope this helps!