There are 10 grams of a substance that decays wiht a half-life of 14 days. How much will there be after 70 days?

Question

Question 7 options:

0.31 g

1.25 g

2.50 g

Answer 1

The amount of the substance remaining after a certain number of half-lives can be calculated using the equation:

Amount remaining = Initial amount x (1/2)^(number of half-lives)

In this case, the initial amount is 10 grams and the half-life is 14 days. To find the number of half-lives in 70 days, we divide 70 by 14:

Number of half-lives = 70 days / 14 days/half-life = 5 half-lives

Plugging these values into the equation, we get:

Amount remaining = 10 g x (1/2)^(5 half-lives) = 10 g x (1/2)^5 = 10 g x (1/32) = 0.3125 g

Therefore, the amount of the substance that will remain after 70 days is approximately 0.31 g.

Answer: 0.31 g