Given that N_{2(g)} + 3 H_{2(g)} longrightarr | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(D) The standard molar enthalpy of formation $(\Delta_f H^{\circ})$ is defined as the enthalpy change when $1 \ mol$ of a substance is formed from its

Vedclass · Accepted Answer

$-46$

Vedclass · Answer

(D) The standard molar enthalpy of formation $(\Delta_f H^{\circ})$ is defined as the enthalpy change when $1 \ mol$ of a substance is formed from its constituent elements in their standard states.
For the reaction: $N_{2(g)} + 3 H_{2(g)} \longrightarrow 2 NH_{3(g)}$, the enthalpy change is $\Delta_r H^{\circ} = -92 \ kJ$ for the formation of $2 \ mol$ of $NH_{3(g)}$.
To find the enthalpy of formation for $1 \ mol$ of $NH_{3(g)}$, we divide the reaction by $2$:
$\frac{1}{2} N_{2(g)} + \frac{3}{2} H_{2(g)} \longrightarrow NH_{3(g)}$
$\Delta_f H^{\circ} = \frac{\Delta_r H^{\circ}}{2} = \frac{-92 \ kJ}{2} = -46 \ kJ \ mol^{-1}$.

Given that $N_{2(g)} + 3 H_{2(g)} \longrightarrow 2 NH_{3(g)}$; $\Delta_r H^{\circ} = -92 \ kJ$, the standard molar enthalpy of formation in $kJ \ mol^{-1}$ of $NH_{3(g)}$ is

Similar Questions

The weight of oxalic acid required to neutralize $100 \, cc$ of a normal solution of $NaOH$ is ........ $gm$.

The complete combustion of one mole of benzene produces how many grams of carbon dioxide?

$10 \ g$ of a piece of marble $(CaCO_3)$ was put into excess of dilute $HCl$ acid. When the reaction was complete,$1120 \ mL$ of $CO_2$ was obtained at $STP$. The percentage of pure $CaCO_3$ in the marble is $............ \%$.

$100 \ mL$ of $PH_3$ on decomposition produces phosphorus and hydrogen. The change in volume is ............... $mL$ increase.

$A$ gaseous mixture contains $CH_4$ and $C_2H_6$ in equimolecular proportion. The weight of $2.24 \ L$ of this mixture at $S.T.P.$ is :- .............. $g$

Vedclass Test Series

Exam Paper Generator

Online Exam Module