Answer :
10 Bi-214 has a half-life of 19.7 minutes. A sample of 100g of Bi-124 is present initially, the mass of Bi-124 remains 98.5 minutes later is C. 3.125g.
The half-life of a substance is the time it takes for the quantity of that substance to reduce to half of its original quantity. In this case, we are looking at the half-life of Bi-214, which is 19.7 minutes. This means that if we start with 100g of Bi-214, after 19.7 minutes, we will have 50g left. After another 19.7 minutes, we will have 25g left, and so on. Now, we are asked to find out what mass of Bi-214 remains after 98.5 minutes.
We can do this by calculating the number of half-lives that have passed, and then multiplying the initial mass by the fraction remaining after that many half-lives. In this case, we have: 98.5 / 19.7 = 5 half-lives.
So, after 5 half-lives, the fraction remaining is (1/2)^5 = 1/32.
Therefore, the mass remaining is: 100g x 1/32 = 3.125g. Hence, the correct option is C. 3.125g.
Learn more about fraction at:
https://brainly.com/question/29766013
#SPJ11
