Chapter 5, Problem 5D.7P

(a)

Interpretation Introduction

Interpretation: The phase diagram for the given $\text{N,N-dimethylacetamide}$ and heptane system against the mole fraction of $\text{N,N-dimethylacetamide}$ in two phases has to be drawn.

Concept introduction: The azeotropic mixture is defined as a mixture of two or more liquids which evaporates without altering the composition of the mixture.  The azeotropic mixture has a constant boiling point because of the same composition in liquid as well as vapor phase.  The components of azeotropic mixture are not separated by distillation processes.

The phase diagram represents the changes in the mixture on changing the conditions like temperature and pressure of the mixture.

(b)

Interpretation Introduction

Interpretation: The proportion and the compositions of the two phases of the mixture by mixing $0.750\text{mol}$ of $\text{N,N-dimethylacetamide}$ and $0.250\text{mol}$ of heptane at $296\text{K}$ have to be stated.  The temperature up to which the mixture has to be heated to form a single phase mixture has to be stated.

Concept introduction: The azeotropic mixture is defined as a mixture of two or more liquids which evaporates without altering the composition of the mixture.  The azeotropic mixture has a constant boiling point because of the same composition in liquid as well as vapor phase.  The components of azeotropic mixture are not separated by distillation processes.

The cooling curve is a graphical representation of change of phase of compound.  It is plotted between temperature and time.