Problem: A gas-phase reaction was run in an apparatus designed to maintain a constant pressure.Using data from Appendix C in the textbook, determine H for the formation of one mole of the product.

🤓 Based on our data, we think this question is relevant for Professor Graham's class at ARIZONA.

We’re being asked to determine the standard enthalpy change of formation (ΔH˚_rxn) for NO.

Recall that ΔH˚_rxn can be calculated from the enthalpy of formation (ΔH˚_f) of the reactants and products involved:

$∆ H_{rxn}^{\circ} = ∆ H_{_{f products}}^{^{\circ}} - ∆ H_{_{f reactants}}^{^{\circ}}$

The chemical equation for that reaction is:

N₂_(g)+ O₂_(g)→ NO_(g)

This equation is not yet balanced. To balance it, we have to make sure that the number of elements on both sides is equal.

Balance N: We have 1 N₂ on the reactant side and 1 O on the product side – add a coefficient of 2 to NO:

N₂(g) + O₂(g)→ 2 NO

A gas-phase reaction was run in an apparatus designed to maintain a constant pressure.

A piston applies pressure to a cylinder containing two O2 molecules and two N2 molecules. This leads to four NO molecules.

Using data from Appendix C in the textbook, determine H for the formation of one mole of the product.