Question

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?

Is it 30000?

Answer 1

Well, what is the relationship between 250 and 1000? @gamer456148

Answer 2

I don't know?

Answer 3

Can you help?

Answer 4

What is 250/1000? @gamer456148

Answer 5

1/4

Answer 6

Is the answer 25000

Answer 7

@gamer456148 There is a half-life of 10,000 years and we have 1/4 the initial mass. 1000/2=500
500/2=250
So there has been two complete half-life cycles, taking a total of 20,000 years.

Answer 8

Wow I was so wrong but how do you determine the half lifes?

Answer 9

20000 years

Answer 10

It is a complicated thing to do for things with long half-lives but it involves some serious accurate molecule/atom counting and extremely high level math.

Answer 11

@gamer456148 By definition a half-life is the amount of time it takes a sample of the target substance with a known weight to lose 50% of the initial mass.