已知：① C(s)＋O₂(g)＝CO₂(g)；          DH＝—393.5 kJ·mol^-1
② 2CO(g)＋O₂(g)＝2CO₂(g)；                DH＝-566 kJ·mol^-1
③ TiO₂(s)＋2Cl₂(g)＝TiCl₄(s)＋O₂(g)；       DH＝+141 kJ·mol^-1
则TiO₂(s)＋2Cl₂(g)＋2C(s)＝TiCl₄(s)＋2CO(g)的DH＝                。