The standard enthalpy of formation of NH_3 is | vedclass

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

Question

(C) The formation reaction is: $\frac{1}{2} N_2(g) + \frac{3}{2} H_2(g) \rightarrow NH_3(g)$; $\Delta H_f = -46.0 \, kJ/mol$. Bond dissociation energi

Vedclass · Accepted Answer

$+352$

Vedclass · Answer

(C) The formation reaction is: $\frac{1}{2} N_2(g) + \frac{3}{2} H_2(g) ightarrow NH_3(g)$; $\Delta H_f = -46.0 \, kJ/mol$. Bond dissociation energies are the negative of the enthalpy of formation from atoms: $BE(N \equiv N) = +712 \, kJ/mol$ $BE(H-H) = +436 \, kJ/mol$. Using the formula: $\Delta H_f = [\frac{1}{2} BE(N \equiv N) + \frac{3}{2} BE(H-H)] - [3 	imes BE(N-H)]$. Substituting the values: $-46.0 = [\frac{1}{2}(712) + \frac{3}{2}(436)] - 3 	imes BE(N-H)$. $-46.0 = [356 + 654] - 3 	imes BE(N-H)$. $-46.0 = 1010 - 3 	imes BE(N-H)$. $3 	imes BE(N-H) = 1010 + 46 = 1056$. $BE(N-H) = 1056 / 3 = 352 \, kJ/mol$.

The standard enthalpy of formation of $NH_3$ is $-46.0 \, kJ/mol$. If the enthalpy of formation of $H_2$ from its atoms is $-436 \, kJ/mol$ and that of $N_2$ is $-712 \, kJ/mol$,the average bond enthalpy of $N-H$ bond in $NH_3$ is......$kJ/mol$

Similar Questions

The heat of formation for the reaction $H_2 + Cl_2 \to 2HCl + 44 \ kcal$ is ..... $kcal \ mol^{-1}$.

When $1 \ mol$ of $NH_4OH$ reacts with $1 \ mol$ of $HCl$,the amount of heat released is.....

The standard heats of formation for $CH_4$, $C_2H_4$, and $C_3H_8$ are $-17.9$, $12.5$, and $-24.8 \ kcal/mol$ respectively. The heat of reaction $(\Delta H)$ for the reaction $CH_4 + C_2H_4 \rightarrow C_3H_8$ in $kcal$ is:

Assertion $(A)$: Formation of $H_2O_{(\ell)}$ from $H_{2(g)}$ and $O_{2(g)}$ is more exothermic than formation of $H_2O_{(g)}$ from $H_{2(g)}$ and $O_{2(g)}$.
Reason $(R)$: $H_2O_{(\ell)}$ has more attraction force than $H_2O_{(g)}$ and it is more stable than $H_2O_{(g)}$.

Which of the following acids will release the maximum amount of heat when completely neutralized by a strong base $NaOH$?

Vedclass Test Series

Exam Paper Generator

Online Exam Module