You begin pouring sodium chloride into a glass of water. For a long time, the sodium chloride just dissolves in the water, but s
2 answers:
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<u>Answer:</u>
<u>For a:</u> The molarity of commercial HCl solution is 12.39 M.
<u>For b:</u> The molality of commercial HCl solution is 16.79 m.
<u>For c:</u> The volume of commercial HCl solution needed is 2.42 L.
<u>Explanation:</u>
We are given:
Mass % of commercial HCl solution = 38 %
This means that 38 grams of HCl is present in 100 grams of solution.
To calculate the volume of solution, we use the equation:
Density of HCl solution = 1.19 g/mL
Mass of solution = 100 g
Putting values in above equation:
- <u>For a:</u>
To calculate the molarity of solution, we use the equation:
We are given:
Molarity of solution = ?
Molar mass of HCl = 36.5 g/mol
Volume of solution = 84.034 mL
Mass of HCl = 38 g
Putting values in above equation, we get:
Hence, the molarity of commercial HCl solution is 12.39 M.
- <u>For b:</u>
To calculate the molality of solution, we use the equation:
Where,
= Given mass of solute (HCl) = 38 g
= Molar mass of solute (HCl) = 36.5 g/mol
= Mass of solvent = 100 - 38 = 62 g
Putting values in above equation, we get:
Hence, the molality of commercial HCl solution is 16.79 m.
- <u>For c:</u>
To calculate the molarity of the diluted solution, we use the equation:
where,
are the molarity and volume of the concentrated solution
are the molarity and volume of diluted solution
We are given:
Putting values in above equation, we get:
Hence, the volume of commercial HCl solution needed is 2.42 L.
Answer:
Explanation:
Hello,
In this case, since the acid is monoprotic, we can notice a 1:1 molar ratio between, therefore, for the titration at the equivalence point, we have:
Thus, solving for the moles of the acid, we obtain:
Then, by using the mass of the acid, we compute its molar mass:
Regards.
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>
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>
</span>t - <span>total time elapsed
</span><span>n - a number of half-lives
</span>
So, we know:
t = 10 min
<span>
We need:
n = ?
x = ?
</span>
We could first use the second equation to calculate n:
<span>If:
</span>Then:
⇒
⇒
</span>
Now we can use the first equation to calculate the remained fraction of the sample.
<span>
</span>⇒
<span>⇒