I cant entirely tell for now but an article on rodioactivity should solve the problem
Answer:

Explanation:
Hello.
In this case, we can solve this problem by applying the Boyle's law which allows us to understand the pressure-volume behavior as a directly proportional relationship:

In such away, knowing the both the initial pressure and volume and the final volume, we can compute the final pressure as shown below:

Consider that the given initial pressure is also equal to Pa:

Which stands for a pressure increase when volume decreases.
Regards.
Answer:
Approximately 0.39 g or 0.4 g if you're rounding up
Explanation:
15/3.82 = 3.92
Let's round that up to 4
That means 15 days is around 4 half lives
4 half lives means 1/16 of the original mass will be left
25/16 = 0.390625
Answer:
Heat
Explanation:
explosions always make heat