Question

Период полураспада кобальта-58 составляет 71 день. Сколько граммов этого изотопа распадется за 213 суток, если в момент начала наблюдения его масса в образце равна 4,0 г?

Answer 1

0 дней-4,0 г
71 день - 2,0 г
71+71=142 дня- 1,0 г
142+71=213 дней-0,5 г

Answer 2

Calculation of Cobalt-58 Decay

To calculate the amount of Cobalt-58 that will decay over a period of 213 days, we need to use the concept of half-life. The half-life of Cobalt-58 is given as 71 days.

The half-life of a radioactive isotope is the time it takes for half of the initial amount of the isotope to decay. In this case, the half-life of Cobalt-58 is 71 days.

To calculate the amount of Cobalt-58 that will decay over 213 days, we can use the following formula:

Amount of Cobalt-58 remaining = Initial amount * (1/2)^(number of half-lives)

Given that the initial mass of the Cobalt-58 sample is 4.0 grams, we can calculate the amount of Cobalt-58 that will decay over 213 days.

Let's calculate it step by step:

1. Calculate the number of half-lives that occur over 213 days: - Number of half-lives = 213 days / 71 days (half-life) = 3 half-lives

2. Calculate the amount of Cobalt-58 remaining after 3 half-lives: - Amount of Cobalt-58 remaining = 4.0 grams * (1/2)^(3 half-lives)

Using the formula, we can calculate the amount of Cobalt-58 that will decay over 213 days.

Calculation:

Amount of Cobalt-58 remaining = 4.0 grams * (1/2)^(3 half-lives)

= 4.0 grams * (1/2)^3

= 4.0 grams * (1/8)

= 0.5 grams

Therefore, 0.5 grams of Cobalt-58 will decay over a period of 213 days, starting with an initial mass of 4.0 grams.

Please note that this calculation assumes that the decay of Cobalt-58 follows a simple exponential decay model and does not take into account any other factors that may affect the decay process.