Question

If a radioisotope has a half-life of 17.5 days, how much of that radioisotope will remain from a 100 gram sample after 70 days?

Answer 1

Answer:

Okay! Had to do some research, but now I'm here.

Explanation:

So, to do this, half-life is a sort of time period where half of the starting material naturally decays into a stable element, such as uranium.

Meaning, after 17.5 days, 50 grams of that radioisotope will be left.

After 35 days (2 half-lives), 25 grams of that radioisotope will be left.

See where I'm getting at?

After 52.5 days, 12.5 grams of the radioisotope will be left.

(It's easier to create a graph, but I'm using a simple progression method to solve this.)

As such, after 70 days, 6.25  grams of that radioisotope will be left.

See? Pretty easy. Just keep adding the amount of the half-life, and divide the starting material by two!

Hope this helps!

Answer 2

Answer:

You can calculate by given steps.

Explanation:

A Use Equation 14.28 to calculate the half-life of the reaction. B Multiply the initial concentration by 1/2 to the power corresponding to the number of half-lives to obtain the remaining concentrations after those half-lives. C Subtract the remaining concentration from the initial concentration.