Chapter 12, Problem 12.40QE

Interpretation Introduction

Interpretation:

The concentration of the sodium hypochlorite expressed in molality, molarity and mole fraction 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,

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

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,

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

Molarity:  Molarity is defined as the mass of solute in one liter of solution.  Molarity is the preferred concentration unit for stoichiometry calculations.  The formula is,

  $\text{Molarity=}\frac{\text{Mass}\text{of}\text{solute(in}\text{grams)}}{\text{Volume}\text{of}\text{solution}\text{(in}\text{litres)}}$