Chapter 9, Problem 70SCQ

(a)

Interpretation Introduction

Interpretation:

The explanation for the same carbon-nitrogen bond length in the melamine ring has to be given.

Concept Introduction

Bond length: It is defined as the distance between the centers of two covalent bonded atoms. The higher bond order the stronger the pull between the two atoms and the shorter the bond length.

Hybridization is the mixing of valence atomic orbitals to get equivalent hybridized orbitals that having similar characteristics and energy.

• Geometry of a molecule can be predicted by knowing its hybridization.
• ${\text{sp}}^{\text{3}}$ hybrid orbitals is produced by hybridization of single s-orbital and three p-orbital.
• ${\text{sp}}^2$ hybrid orbitals is produced by hybridization between one s-orbital and two p-orbitals.
• $\text{sp }$ hybrid orbitals is produced by hybridization of single s-orbital and single p-orbital.

(b)

Interpretation Introduction

Interpretation:

The enthalpy change for the production of melamine by the decomposition of urea has to be given.

Concept Introduction

Enthalpy is the amount of energy absorbed or released in a process.

The enthalpy change in a system $\text{(Δ}{{\rm H}}_{\text{sys}}\text{)}$ can be calculated by the following equation.

  $\Delta {\text{H}}^{°}={\displaystyle \sum n{H}_{fproducts}^{{}^{\text{ο}}}-}{\displaystyle \sum m{H}_{f\mathrm{Re}ac\tan ts}^{{}^{\text{ο}}}}$

Where,

  ${\text{ΔH}}^{\text{°}}{}_{\text{reactants}}$ is the standard enthalpy of the reactants

  ${\text{ΔH}}^{\text{°}}{}_{\text{produdcts}}$ is the standard enthalpy of the products