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3 years ago

A) How do you prepare %3 (w/v) Na2CO3 solution from Na2CO3⸱2H2O? (15p) Na2CO3 MW=106 g/mol

Chemistry

1 answer:

just olya [345]3 years ago

8 0

Answer:

4.02g of Na2CO3⸱2H2O must be added completing the volume of the solution to 100mL

Explanation:

A 3%(w/v) solution contains 3g of solute (In this case, Na2CO3) in 100mL of solution.

Assuming we require 100mL of solution we must add 3g of Na2CO3. The reactant that is available is its dihydrate, with molar mass:

106g/mol + 2*MW H2O

106g/mol + 2*18g/mol = 142g/mol

That means the mass of Na2CO3.2H2O that must be added to prepare the solution is:

3g Na2CO3 * (142g/mol Na2CO3.2H2O / 106g/mol Na2CO3) =

<h3>4.02g of Na2CO3⸱2H2O must be added completing the volume of the solution to 100mL</h3>

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Hemoglobin, an iron-containing oxygen-transport protein, is 0.349% Fe by mass.

nirvana33 [79]

Answer : The molar mass of hemoglobin is, $6.40\times 10^4g/mol$

Explanation : Given,

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or,

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Now put all the given values in this formula, we get:

$0.349=\frac{4\times 55.85g/mol}{\text{molar mass of hemoglobin}}\times 100$

$\text{molar mass of hemoglobin}=64011.46g/mol=6.40\times 10^4g/mol$

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4 years ago

How does direct current differ from<br> alternating current ?

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A direct current flows in one direction and an alternating currents flow consists of electrons switching back and forth

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3 years ago

A magnesium ion, Mg2+, is formed from a magnesium atom, Mg.

konstantin123 [22]

Answer:

The correct row is B.

Explanation:

The formation of the magnesium ion, Mg²⁺, comes from the removal of 2 electrons from the valence shell of the magnesium atom.<em> </em>Since the remotion is of electrons, the nucleus of the atom remains the same, so the number of protons and the number of neutrons does not change.<em> </em>

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Therefore, the correct row is B.

I hope it helps you!

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Titration is also known as titrimetry is a technique where a solution of known concentration is used to calculate the concentration of the unknown solution. Titration is a laboratory technique.

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Learn more about the Titration here: brainly.com/question/186765

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