Chapter 12, Problem 12.17QE

(a)

Interpretation Introduction

Interpretation:

The concentration of benzoic acid in mass percentage has to be calculated.

Concept Introduction:

Mass percentage:  The mass percentage gives the number of grams of solute present in 100g of solution.  The formula of mass percentage is,

  $\text{Mass}\text{percentage=}\frac{\text{Grams}\text{of}\text{solute}}{\text{Grams}\text{of}\text{solution}}\text{×100\%}$

(b)

Interpretation Introduction

Interpretation:

The concentration of benzoic acid in mole fraction has to be calculated.

Concept Introduction:

Mole fraction:  Mole fraction of a substance in a solution is the number of moles of that substance divided by the total number of moles of all substances present.  The formula is,

  $\begin{array}{l}{\text{χ}}_{\text{A}}\text{=}\frac{\text{Moles}\text{of}\text{A (in}\text{mol)}}{\text{Moles}\text{of}\text{A (in mol) +Moles}\text{of}\text{B (in mol) +Moles}\text{of}\text{C (in mol) +}\mathrm{...}}\\ \\ {\text{χ}}_{\text{A}}\text{=}\frac{\text{Moles}\text{of}\text{A (in}\text{mol)}}{\text{Total}\text{number}\text{of}\text{moles}\text{of}\text{components}\text{(in}\text{mol)}}\end{array}$

(c)

Interpretation Introduction

Interpretation:

The concentration of benzoic acid in molality has to be calculated.

Concept Introduction:

Molality:  Molality is defined as moles of solute per specified amount of mass of the solvent.  The formula is,

  $\text{Molality}\text{(m)=}\frac{\text{Mass}\text{of}\text{solute (in mol)}}{\text{Mass}\text{of}\text{solvent (in kg)}}$