If the standard enthalpy change left(Delta_{r | vedclass

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

Question

(A) The standard enthalpy of formation $\Delta_{f} H^	heta$ is defined as the enthalpy change when $1 \ mol$ of a substance is formed from its consti

Vedclass · Accepted Answer

$-36.4$

Vedclass · Answer

(A) The standard enthalpy of formation $\Delta_{f} H^	heta$ 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 $H_{2(g)} + Br_{2(l)} ightarrow 2 HBr_{(g)}$,the enthalpy change $\Delta_{r} H^	heta$ is given as $-72.8 \ kJ$ for the production of $2 \ mol$ of $HBr_{(g)}$. The relationship between reaction enthalpy and enthalpy of formation is: $\Delta_{r} H^	heta = \sum \Delta_{f} H^	heta 	ext{(products)} - \sum \Delta_{f} H^	heta 	ext{(reactants)}$ Since $\Delta_{f} H^	heta$ for elements in their standard states ($H_{2(g)}$ and $Br_{2(l)}$) is $0$,we have: $-72.8 \ kJ = 2 	imes \Delta_{f} H^	heta (HBr_{(g)}) - (0 + 0)$ $\Delta_{f} H^	heta (HBr_{(g)}) = \frac{-72.8 \ kJ}{2 \ mol} = -36.4 \ kJ \ mol^{-1}$.

If the standard enthalpy change $\left(\Delta_{r} H^\theta\right)$ for the reaction $H_{2(g)} + Br_{2(l)} \rightarrow 2 HBr_{(g)}$ is $-72.8 \ kJ$,the standard enthalpy of formation $\left(\Delta_{f} H^\theta\right)$ of $HBr_{(g)}$ (in $kJ \ mol^{-1}$) is

Similar Questions

What is bond enthalpy? Explain bond enthalpy in polyatomic molecules like $H_2O$.

For the reactions $(i) \, H_{2(g)} + Cl_{2(g)} \to 2HCl_{(g)} + x \, kJ$ and $(ii) \, H_{2(g)} + Cl_{2(g)} \to 2HCl_{(\ell)} + y \, kJ$,which of the following statements is correct?

The enthalpy of neutralization of a strong acid by a strong base is $-57.32 \ kJ/mol$. The enthalpy of formation of water is $-285.84 \ kJ/mol$. The enthalpy of formation of hydroxyl ion is......$kJ/mol$. (Assume $\Delta H_{f}^{\circ}(H^{+}_{(aq)}) = 0 \ kJ/mol$)

Find the standard enthalpy of formation of $SO_{3(g)}$ from the following reactions:
$S_{8(s)} + 8O_{2(g)} \to 8SO_{2(g)}$; $\Delta H_1 = -2775 \ kJ/mol$
$2SO_{2(g)} + O_{2(g)} \to 2SO_{3(g)}$; $\Delta H_2 = -198 \ kJ/mol$

Which of the following is not an endothermic reaction?

Vedclass Test Series

Exam Paper Generator

Online Exam Module