Consider the following reaction P₄(g) → 2 P₂(g) with a ΔH° value of +229.1 kJ. If the P–P bond has an average bond dissociation energy of 197 kJ/mol, estimate the value of the P≡P triple bond energy in P₂(g).

Acetylene in nature is formed from the thermal decomposition of long-chain hydrocarbons at high temperatures (1700 K). Acetylene is a hydrocarbon composed of two carbon and two hydrogen atoms. The decomposition reaction for acetylene is:
C₂H₂(g) → 2 C(s) + H₂(g)
Use bond energies to explain why this reaction is improbable. The bond energies are:
H-H: 432 kJ/mol
C≡C: 839 kJ/mol
C-H: 413 kJ/mol

Consider a photon with enough energy to break an N-N bond. Will the same photon be able to break an N-H bond based on average bond enthalpies?

Phosphoryl chloride (POCl₃) can be formed from the reaction of phosphorus trichloride (PCl₃) and oxygen gas (O₂). The unbalanced reaction is shown below:

PCl₃(g) + O₂(g) → POCl₃(g)

In POCl₃, the O atom and the three Cl atoms are bonded to the central P atom. Referring to the given in the table below, calculate the approximate enthalpy of the reaction and determine whether the reaction is endothermic or exothermic.