# Given<

Given: For the given reaction,

N2(g) + 3H2(g) 2NH3(g)

Enthalpy of reaction (ΔrH°) = –92.4 kJ mol–1

To calculate standard enthalpy of formation of NH3 gas, first we will divide the whole reaction by 2, so that we get 1 mol of NH3

N2 (g) + H2(g) NH3(g)

Hence, standard enthalpy of NH3 is equal to the 1/2 ΔrH°

As, ΔrH° = –92.4 kJ mol–1

Standard enthalpy of NH3 =

Standard enthalpy of NH3 = -46.2 kJ mol-1

Thus, standard enthalpy of formation of NH3 gas = -46.2 kJ mol-1

Note: Standard enthalpy of formation is the amount of heat absorbed or evolved when 1 mole of the substance is directly obtained from its constituent elements.

Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
view all courses