Chapter 5, Problem 70QP

Interpretation Introduction

Interpretation:

The heat released (in kJ) when ammonia is producedinthegiven reaction is to be calculated.

Concept introduction:

The standard enthalpy for a reaction is the change in enthalpythat occursunder standard conditions, that is, at room temperature and pressure(27°C and 1 atm).

The standard enthalpy of the reaction is to be determined using the equation given below:

$\Delta H{°}_{\text{rxn}}={\displaystyle \sum n}\Delta H_{\text{f}}^{°}\left(\text{products}\right)-{\displaystyle \sum m}\Delta H_{\text{f}}^{°}\left(\text{reactants}\right)$

Here, the stoichiometric coefficients are represented by m for reactants and n for products, and enthalpy of formation under standard conditions is represented by $\Delta H_{\text{f}}^{°}$.

The value of enthalpy of formation of an element is zero at its most stable state.