Question

Use Hess's law to calculate δH for the following reaction:

N₂O(g)+NO₂(g) → 3NO(g).
a. δH = −95.6kJ
b. δH = −229.3kJ
c. δH = −324.9kJ
d. δH = −76.4kJ

Answer 1

Using Hess's Law, the enthalpy change (ΔH) for the reaction N₂O(g) + NO₂(g) → 3NO(g) is calculated by summing the enthalpy changes of given reference reactions, resulting in a ΔH of -138.4 kJ.

Step-by-step explanation:

To calculate the enthalpy change (ΔH) for the reaction N₂O(g) + NO₂(g) → 3NO(g) using Hess's Law, we need to consider the given enthalpy changes for the reference reactions provided. Hess's Law states that the total enthalpy change for a chemical reaction is the same, regardless of the pathway by which the reaction occurs, provided the initial and final conditions are the same. By summing the enthalpy changes of the individual reactions, we obtain the enthalpy change for the overall reaction:

ΔH³₍n = ΔH₁ + ΔH₂ + ΔH₃ + ΔH₄ = (-99.6 kJ) + (+285.8 kJ) + (-414.8 kJ) + (+90.2 kJ) = -138.4 kJ

This value is the combined enthalpy change for the reaction sequence which yields our target reaction. Therefore, we conclude that the ΔH for the reaction N₂O(g) + NO₂(g) → 3NO(g) is -138.4 kJ.