The half life of a radioactive element is the time needed to the element to decay and reach the half amount of the initial amount. Here we have a radioisotope element which decays its half from 10,000 to 5,000 in two days. Therefore, its half life is 2 days.
Answer:

Explanation:
Hello,
In this case, the dissociation of the given weak acid is:

Therefore, the law of mass action for it turns out:
![Ka=\frac{[H^+][A^-]}{[HA]}](https://tex.z-dn.net/?f=Ka%3D%5Cfrac%7B%5BH%5E%2B%5D%5BA%5E-%5D%7D%7B%5BHA%5D%7D)
That in terms of the change
due to the reaction extent is:

Thus, by solving with the quadratic equation or solver, we obtain:

Which clearly matches with the hydrogen concentration in the solution, therefore, the pH is:

Regards.
The bubbles are Carbon dioxide gas
Answer: cools down and keeps going
Explanation:
Answer:
The specific heat capacity of glass is 0.70J/g°C
Explanation:
Heat lost by glass = heat gained by water
Heat lost by glass = mass × specific heat capacity (c) × (final temperature - initial temperature) = 58.5×c×(91.2 - 21.7) = 4065.75c
Heat gained by water = mass × specific heat capacity × (final temperature - initial temperature) = 250×4.2×(21.7 - 19) = 2835
4065.75c = 2835
c = 2835/4065.75 = 0.70J/g°C