n = 1kmol = 1000 moli C₂H₂
C₂H₂(g) + 5/2O₂(g) ⇒ 2CO₂(g) + H₂O(g)
ΔH = 2ΔfH°CO₂(g) + ΔfH°H₂O(g) - [(ΔfH°C₂H₂+5/2ΔfH°O₂(g))] = 2*(-393,5) + (-241,8) - [(-227+0)] = -1255,8 KJ/mol
1 mol C₂H₂..............................1255,8 KJ
1000 moli................................Q = 1255800 KJ = 1255,8 MJ