Asked by h

A substance has a half-life of 10,000 years and an initial mass of 1,000 grams. How many years will pass before only 250 grams of the substance's parent material is left?
Answered by bobpursley
1000...500....250 Isn't that two half years?
Answered by Bosnian
After 10 000 yrs, 1 000 / 2 = 500 grams of the substance's parent material is left.

After next 10 000 yrs, 500 / 2 = 250 grams of the substance's parent material is left.


10 000 yrs + 10 000 yrs = 20 000 yrs
Answered by bobpursley
I agree with Bosnian, I misread the half-life as 1000 years. Yes, two half lives is 20,000 years.