The answer is 1/16.
Half-life is the time required for the amount of a sample to half its value.
To calculate this, we will use the following formulas:
1.

,
where:
<span>n - a number of half-lives
</span>x - a remained fraction of a sample
2.

where:
<span>

- half-life
</span>t - <span>total time elapsed
</span><span>n - a number of half-lives
</span>
So, we know:
t = 10 min
<span>

= 2.5 min
We need:
n = ?
x = ?
</span>
We could first use the second equation to calculate n:
<span>If:

,
</span>Then:

⇒

⇒

<span>
</span>
Now we can use the first equation to calculate the remained fraction of the sample.
<span>

</span>⇒

<span>⇒

</span>
There is a difference between the meanings of the chemistry terms atomic mass and mass number. One is the average weight of an element and the other is the total number of nucleons in the atom's nucleus. ... The mass number is a count of the total number of protons and neutrons in an atom's nucleus.
Answer:
The pH is 11
Explanation:
Because pH + pOH = 14
and pOH = - log [OH⁻] = - log (1 x 10⁻³) = 3
we can now calculate pH by manipulating equation one above
pH = 14 - pOH = 14 - 3 = 11
Thus the pH of the solution is 11