contestada

Os-182 has a half-life of 21.5 hours. How many grams of a 10.0 gram sample would
have decayed after exactly three half-lives?​

Respuesta :

Answer:

8.75 g

Explanation:

  • The half-life of Os-182 is 21.5 hours, which means it takes 21.5 hours for a sample of Os-182 to decay to a half of its initial amount.

We are given;

Mass of Os-182 sample = 10.0 g

Number of half lives = 3

Half life = 21.5 hours

We need to determine the mass that decayed after 3 half lives

Using the formula;

Remaining mass = Initial mass × (1/2)^n , where n is the number of half lives

Therefore;

Mass remaining = 10.0 g × (1/2)^3

                          =1.25 g

Thus, to get the mass that decayed;

Mass that decayed = Initial mass - remaining mass

                                = 10.0 g - 1.25 g

                                = 8.75 g

Hence, the mass of Os-182 that decayed is 8.75 g