Answer:
0.00840
Explanation:
The computation of the mole fraction is as follow:
As we know that
Molar mass = Number of grams ÷ number of moles
Or
number of moles = Number of grams ÷ molar mass
Given that
Number of moles of CaI2 = 0.400
And, Molar mass of water = 18.0 g/mol
Now Number of moles of water is
= 850.0 g ÷ 18.0 g/mol
= 47.22 mol
And, Total number of moles is
= 0.400 + 47.22
= 47.62
So, Molar fraction of CaI2 is
= 0.400 ÷ 47.62
= 0.00840
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>
Water is called the "universal solvent" because it is capable of dissolving more substances than any other liquid. This is important to every living thing on earth. It means that wherever water goes, either through the air, the ground, or through our bodies, it takes along valuable chemicals, minerals, and nutrients.
I would say you should use or test it once a week to ensure it is working properly in an active laboratory since it is a workplace with significant chemical hazards so it would give peace of mind to know on a quite regular basis that it can be relied on in case of an emergency like an eye flush for example.