因B为氮元素,断裂1molB-B吸收167kJ的热量,生成1molB≡B放出942kJ热量,则N4(g)═2N2(g)的△H=167×6-2×942=-882 kJ/mol,
故答案为:N4(g)═2N2(g)△H=-882kJ/mol