Calculate the enthalpy change for the hypothetical reaction

A(s) + 2 B₂(g) → AB₄(g)

Given the enthalpy values for the following reactions

AB₄(g) + 2 C₂(g) → AC₂(g) + 2 B₂C(l)

ΔH = −790.2 kJ

A(s) + C₂(g) → AC₂(g)

ΔH = −291.5 kJ

B₂(g) + 1/2 C₂(g) → B₂C (g)

ΔH = −175.5 kJ