Chapter 12.4, Problem 12.27QAP

Interpretation Introduction

Interpretation:

The difference between a 5.00% (m/m) glucose solution and a 5.00% (m/v) glucose solution should be explained.

Concept Introduction:

Mass percent (m/m) defines the mass of solute in 100 g of the solution. It is calculated by multiplying the ratio of mass of solute to the mass of solution by 100%.

The unit of both mass of solute and solution must be same in the calculation.

Mass of solution is calculated by taking sum of mass of solute and solvent.

Mathematically,

  $\begin{array}{l}\text{mass percent}\left(m/m\right)=\frac{\text{mass of solute}\left(g\right)}{\text{mass of solute}\left(g\right)+\text{mass of solvent}\left(g\right)}\times 100\%\\ =\frac{\text{mass of solute}\left(g\right)}{\text{mass of solution}\left(g\right)}\times 100\%\end{array}$

Similarly, mass/volume percent (m/V) concentration is defined as the mass of solute in grams for 100 mL of the solution. Here, mass of solute should be in grams and unit of volume of solution should be in millilitres.

Mathematically,

  $\begin{array}{l}\text{mass /volume percent}\left(m/V\right)=\frac{\text{mass of solute}\left(g\right)}{\text{volume of solute}\left(\text{mL}\right)+\text{volume of solvent}\left(\text{mL}\right)}\times 100\%\\ =\frac{\text{mass of solute}\left(g\right)}{\text{volume of solution}\left(\text{mL}\right)}\times 100\%\end{array}$