We are asked to calculate the value of ΔH˚ for 4 NH_{3}(g) + O_{2}(g) → 2 N_{2}H_{4}(g) + 2 H_{2}O(l)

$\overline{){\mathbf{\Delta H}}{{\mathbf{\xb0}}}_{{\mathbf{rxn}}}{\mathbf{=}}{\mathbf{\Delta H}}{{\mathbf{\xb0}}}_{\mathbf{f}\mathbf{,}\mathbf{}\mathbf{product}}{\mathbf{-}}{\mathbf{\Delta H}}{{\mathbf{\xb0}}}_{\mathbf{f}\mathbf{,}\mathbf{reactant}}}$

Note that we need to *multiply each ΔH˚ by the stoichiometric coefficient* since ΔH˚ is in kJ/mol.

Balanced reaction : 4 NH_{3}(g) + O_{2}(g) → 2 N_{2}H_{4}(g) + 2 H_{2}O(l)

You may want to reference (Pages 187 - 190) Section 5.7 while completing this problem.

Using values from Appendix C, calculate the value of ΔH˚ for each of the following reactions.

4 NH_{3}(g) + O_{2}(g) → 2 N_{2}H_{4}(g) + 2 H_{2}O(l)

Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Enthalpy of Formation concept. You can view video lessons to learn Enthalpy of Formation. Or if you need more Enthalpy of Formation practice, you can also practice Enthalpy of Formation practice problems.