Chapter 11, Problem 11.67SP

(a)

Interpretation Introduction

Interpretation:

The concentration of the given lactose solution in the units of mole fraction has to be calculated

Concept introduction:

Mole fraction of a compound can be defined as the number of moles of a substance to the total number of moles present in them.  The mole fraction can be calculated by,

$\text{Mole}\text{fraction}\text{of}\text{compound}\text{=}\frac{\text{Number}\text{of}\text{moles}\text{(in}\text{mol)}}{\text{Total}\text{number}\text{of}\text{moles}\text{(in}\text{mol)}}$

(b)

Interpretation Introduction

Interpretation:

The concentration of the given lactose solution in the units of mass percent has to be calculated

Concept introduction:

The mass percentage of a compound can be defined as the ratio taken by the calculated mass to the total mass of a compound by 100.  It can be given by the formula

$\text{mass}\text{percentage}\text{=}\frac{\text{Caclulated}\text{mass}}{\text{Total}\text{mass}}\text{×}\text{100}$

(c)

Interpretation Introduction

Interpretation:

The concentration of the given lactose solution in the units of molality has to be calculated

Concept introduction:

Molality of a solution also called as molal concentration can be defined as the mass of solute in grams to the mass of the solvent in kilograms.  It can be given by the equation,

$\text{Molality(mol}{\text{kg}}^{\text{-1}}\text{)=}\frac{\text{Mass}\text{of}\text{solue(in}\text{g)}}{\text{Mass}\text{of}\text{solvent(in}\text{kg)}}$