Chapter 14.2, Problem 15PP

Interpretation Introduction

Interpretation:

The amount of aqueous solution of $15\%$ methanol by volume is produced from $18mL$ methanol is to be calculated.

Concept introduction:

The concentrations of solutions are expressed in different ways, all of them involved in the quantity of solute and the quantity of solution or solvent. Among them, Volume/volume percentage (v/V percent) is used to express the concentration of solution.

Volume/volume percentage (v/V percent):

Percent by volume usually describes solutions in which both solute and solvent are liquids. It is expressed as the ratio of the volume of the solute to the total volume of the solution multiplied by 100.

In expression (v/V) % $=\frac{Volumeofsolute}{Volumeofsolution}\times 100$

Answer to Problem 15PP

$120mL$ aqueous solution of $15\%$ methanol by volume is produced from $18mL$ methanol.

Explanation:

$15\%$ Methanol by volume means 15 mL methanol is added to $\text{85 }mL$ of water to make a total volume of $100mL$.

$=\frac{Volumeofsolute}{Volumeofsolution}\times 100$

If we write in equation,

Percent by volume of methanol $=\frac{Volumeofmethanol}{Volumeofsolution}\times 100$

Data given: volume of methanol = $18mL$

Percent by volume of methanol = $15\%$

$15\%$

$=\frac{18}{Volumeofsolution}\times 100$

$Volumeofsolution=\frac{18\times 100}{15}$

= $120mL$

$120mL$ Aqueous solution of $15\%$ methanol by volume is produced from $18mL$ methanol.

Explanation of Solution

$15\%$ Methanol by volume means 15 mL methanol is added to $\text{85 }mL$ of water to make a total volume of $100mL$.

$=\frac{Volumeofsolute}{Volumeofsolution}\times 100$

If we write in equation,

Percent by volume of methanol $=\frac{Volumeofmethanol}{Volumeofsolution}\times 100$

Data given: volume of methanol = $18mL$

Percent by volume of methanol = $15\%$

$15\%$

$=\frac{18}{Volumeofsolution}\times 100$

$Volumeofsolution=\frac{18\times 100}{15}$

= $120mL$

Conclusion

$120mL$ Aqueous solution of $15\%$ methanol by volume is produced from $18mL$ methanol.