Question

Which of these would be the correct equation to accompany the heat of formation value for NO2(g), AHNO2 (g) = 34 kJ/mol? NO2 (1) ► NO2 (8) ON (g) + O2(g) → NO2 (g) N2(g) + 2 O2(g) → 2 NO2 (g) OYN2 (g) + O2(g) → NO2 (g)

Answer 1

The correct equation to accompany the standard heat of formation for NO2(g) is N2(g) + O2(g) → NO2(g), which reflects the formation of one mole of nitrogen dioxide from nitrogen and oxygen gases under standard conditions.

Step-by-step explanation:

The correct equation to accompany the standard heat of formation value for NO2(g), represented by ΔH°f[NO2(g)] = 33.2 kJ/mol, would involve the formation of NO2 from its constituent elements in their standard states. According to the definition of standard enthalpy of formation, we need an equation where 1 mole of product, NO2(g), is formed from the elements in their most stable forms under standard conditions (1 atm and 25°C).

This leads us to the balanced chemical equation:
N2(g) + O2(g) → NO2(g)

In this equation, we have one mole of nitrogen gas (N2) reacting with one mole of oxygen gas (O2) to form one mole of nitrogen dioxide (NO2). The enthalpy change for this reaction corresponds to the standard enthalpy of formation for NO2.