Question

A lowered level of sodium ions in the blood of the average female adult would be 0.125 mol L and would be cause for concern. The average adult female has a total blood volume of 4.60 L. Calculate the total mass of sodium ions present when this concentration is found, assuming a blood volume of 4.60 L. Select one: O a. 13.2 g O b. 1.60 g O c. 2.87 g O d. 0.625 g O e. 40.0 g O f. 33.6 g

Answer 1

Given molar concentration \(=0.125 \mathrm{~mol} / \mathrm{L}\)

Volume \(=4.60 \mathrm{~L}\)

As,

Molarity \(=\) Number of moles / Volume of solution in L

So,

Number of moles of \(\mathrm{Na}^{+}\) ion \(=\) Molarity of \(\mathrm{Na}^{+}\) ion \(\mathrm{x}\) Volume of solution in \(\mathrm{L}\)

\(=0.125 \mathrm{~mol} / \mathrm{L} \times 4.60 \mathrm{~L}\)

\(=0.575 \mathrm{~mol}\)

Also,

Mass of \(\mathrm{Na}^{+}\) ion \(=\) Number of moles of \(\mathrm{Na}^{+}\) ion \(\times\) Gram molar mass of \(\mathrm{Na}^{+}\) ion

\(=0.575 \mathrm{~mol} \times 23 \mathrm{~g} / \mathrm{mol}\)

\(=13.2 \mathrm{~g}\)

Therefore, mass of \(\mathrm{Na}^{+}\) ion \(=13.2 \mathrm{~g}\)

So, option (a) is the answer.