Chapter 14, Problem 14.43P

(a)

Interpretation Introduction

Interpretation:

The balanced equation for the formation of $\text{BN}$ has to be written.

Concept Introduction:

Balanced equation:

In a chemical equation, the number of atoms or elements that present in both reactant and product sides are equal means this equation is known as balanced equation.

(b)

Interpretation Introduction

Interpretation:

Enthalpy change of a reaction of formation of Boron nitride has to be calculated.

Concept Introduction:

Hess's law:

Hess's law state that the different in enthalpy change of reactant to product is known as enthalpy change of a reaction.

The enthalpy change reactant to product is calculated by subtraction of standard enthalpy of formation (SEF) of reactant from SEF product.

    $\begin{array}{l}{\text{ΔH}}_{{}_{\text{reaction}}}^{\text{o}}\text{=}{\displaystyle \sum {\text{mΔH}}_{{}_{\text{product}}}^{\text{o}}}\text{-}{\displaystyle \sum {\text{nΔH}}_{{}_{\text{reactant}}}^{\text{o}}}\\ \text{where,}\\ {\text{ΔH}}_{{}_{\text{reaction}}}^{\text{o}}\text{=}\text{enthalpy change}\text{ofreaction}\\ {\text{ΔH}}_{{}_{\text{Product}}}^{\text{o}}\text{=}\text{standard enthalpy of formation of reactant}\\ {\text{ΔH}}_{{}_{\text{reactant}}}^{\text{o}}\text{=standard enthalpy of formation of product}\end{array}$

(c)

Interpretation Introduction

Interpretation:

The amount of borax is needed to produce $\text{1}\text{.0 kg of BN}$ at $\text{72\%}$ yield has to be calculated.

Concept Introduction:

Percentage yield:

Percentage yield is given by,

    $\text{\%Y}\text{=}\frac{\text{Actual yield}}{\text{Theoretical yield}}\times 100$

Mole:

Mole of the solid substance is given by,

    $\text{Mole}\text{=}\frac{\text{Mass}}{\text{Molar}\text{mass}}$